How to Pour Concrete
|
DETERMINING THE TYPE OF CONCRETE TO USE
- You can use many different types of concrete. Ready-mix concrete, which requires only the addition of water, is the simplest to use. It is ideal for small jobs but can be quite expensive for big projects.
- Transit-mix concrete is delivered to the job site in revolving barrel trucks. This is the simplest and easiest way to buy concrete for large projects. However, you'll be paying for the delivery of the concrete and the convenience of premixing. Check local sources for competitive prices on transit-mix concrete.
- You-Haul concrete is available in some areas. You buy the concrete and rent a You-Haul trailer mixer for transporting the concrete to the work site with your car or truck. Again, you have to pay for the premixing and the trailer rental. Check locally for prices on You-Haul concrete.
- The least expensive way to purchase concrete for large projects is to buy the dry ingredients and mix them yourself at the job site. Of course, this requires a lot of work, and you must either rent or purchase the necessary mixers and other equipment.
- The type of concrete you use will be based on the amount of concrete you need and local prices for the various types.
|
|
|
MIXING YOUR OWN CONCRETE
- There are four basic elements in concrete: Portland cement; a fine aggregate, such as sand; a coarse aggregate, such as crushed rock or gravel; and water.
- The aggregates (sand and gravel) usually make up from 2/3 to 3/4 of the volume of any finished concrete. All aggregates should be clean and free of organic matter.
- The water used for mixing concrete should be clean and free of acids, alkalies, oils and sulfates.
- Although the ingredients in concrete are always the same, the finished results depend on the proper mix of the four elements.
- The proper mix of ingredients is determined by the intended use of the concrete.
- For foundations and retaining walls, use about 6-1/4 gallons of water for each sack of cement if the sand is damp. However, if the sand is wet, 5-1/2 gallons of water will easily do the job.
- Concrete that's mixed for pouring sidewalks, stepping stones, slabs, etc., requires about 5-3/4 gallons of water per sack of cement if the sand is damp and about 5 gallons if the sand is wet.
- If you are pouring heavy footings for walls where waterproofing is not a factor, mix the concrete with 1 part cement, 3 parts sand and 4 parts gravel.
- For sidewalks, steps, driveways, etc., use 1 part Portland cement, 2 parts sand and 3 parts gravel.
- For small jobs, you can measure the ingredients using an ordinary galvanized or plastic pail.
- A wooden box measuring 12" x 12" x 12" can give you an accurate measurement for 1 cubic foot of sand or concrete.
- Nail 3/4" half-round to one side of the box at carefully measured points. This will allow you to measure 1/4, 1/2 and 3/4 of a cubic foot.
- Always follow the mixing instructions on the bag when mixing your concrete.
|
|
|
|
ESTIMATING THE MATERIALS NEEDED
|
|
|
BUILDING THE FORMS FOR POURING CONCRETE
- Almost any concrete job requires some type of form. In some cases, forms are built above the ground while others require digging.
- Dig down to the desired level, and build forms to the shape and size needed for the concrete job you are starting.
- Use temporary posts to establish the proper grade or slope of the concrete.
- Nail the stakes lightly to the forms used, or clamp the forms temporarily to the stakes with a "C" clamp.
- Use a level to ensure that you have the proper grade or slope of the concrete form.
- After the proper grade has been set, drive in permanent stakes and nail the form to the stakes.
|
|
|
|
POURING CONCRETE
- After the forms are set, spray the entire area lightly with a garden hose, then pour in the concrete.
- After the form is filled, tamp the freshly poured concrete to compact it. Use a tamper, or put on rubber boots and walk around the poured concrete area to make sure it is compacted around the edges.
- Small concrete areas can be compacted with a 2x4. For larger areas, you may want to rent roller tampers.
- After the concrete in the form has been thoroughly tamped, use a straight-edged 2x4 as a screed for leveling the concrete.
- Work the 2x4 back and forth in sawing fashion to level the concrete at all points across the form.
- Purchase a magnesium concrete rake with an extension handle to level concrete in hard-to-reach places.
- When the concrete has set sufficiently to support a 2x8 plank, use the plank as a straightedge to guide a groover to cut contraction joints. Contraction joints are necessary to allow hardened concrete to expand and contract in extreme temperatures.
- On sidewalks or other narrow concrete areas, contraction joints should be cut every 4' to 6'.
- On patios or other large concrete areas, expansion joints should be cut in each direction every 4' to 6'. Use two lengths of beveled clapboard placed in the position shown to cut these joints.
- Drive a nail into the top of one board and paint both boards with motor oil. The boards should then be embedded in the concrete, as shown in.
- After the concrete begins to set, the board with the nail in the top can be removed, leaving the second board hidden. This provides an adequate contraction joint for a large expanse of concrete.
|
|
|
|
REINFORCING CONCRETE
- In some cases, concrete needs reinforcement with steel mesh. You can use regular fencing material with 2' x 4' or 2' x 6' mesh.
- If the pressure on the concrete is to come from the top of the slab, the reinforcement should be laid deep near the bottom of the slab.
- If the strong point of the slab is at the center and the pressure will come on either end, the reinforcement should be laid as close to the top of the slab as possible.
|
|
|
|
DIFFERENT WAYS TO FINISH CONCRETE
- You can give concrete a smooth finish with a trowel and a float. The float will smooth out the concrete on the first rubbing.
- A trowel is used to give the concrete a finishing touch.
- You can create a light, swirled pattern by holding a steel trowel flat against the surface of the slab and moving it around in a swirling motion. Do this the last time you trowel the concrete.
- For a heavier swirling pattern, use a wood float instead of a trowel and do the swirling while the concrete is still fairly wet.
- Create a soft pattern of parallel lines by dragging a soft brush straight across a moderately wet surface.
- To achieve heavy lines, drag the soft-brush across while the surface is still wet.
- For light-textured parallel lines, trowel the concrete and allow it to dry slightly before dragging the brush across.
- Use an ordinary broom to create a very attractive and practical pattern in concrete. This technique provides a rough finish that makes the concrete surface much safer when wet.
- You can make all brush strokes in the same direction, or each block between contraction joints can be brushed in opposite directions for a unique appearance.
- Use an ordinary garage floor brush to create attractive wavy patterns in newly laid concrete. The wavy patterns enhance the appearance and make the surface safer when wet.
- You can create a flagstone pattern by tooling the concrete after it has been leveled off with a darby or float. To make the flagstone pattern, use an 18" length of 1/2" or 3/4" copper pipe that is slightly bent.
- Trowel and brush the concrete surface lightly after the flagstone pattern has been created in the wet concrete.
- There are also forms available for concrete that will create a flagstone walk. These work extremely well for smaller projects. For larger areas a relative new concrete stamping process creates the same look on driveways and patios. Contractors, due to the cost of the equipment needed, normally do this concrete stamping.
- Whatever pattern you choose to create, remember, the pattern should not trap water and cause it to stand on the concrete. Standing water is one of the major causes for concrete failure.
- Special colorants are available for concrete. When added to the concrete mix, these colorants can make concrete look like red brick or any number of other materials. Concrete can be colored to accent the color of your home.
|
|
|
|
LETTING THE CONCRETE CURE
- All concrete must be given time to cure. During this period, the concrete surface should be kept wet by repeated hosing with a fine mist.
- This hosing process should be done at least twice during any 24-hour period for about three days after the concrete is poured.
- Concrete poured indoors can be left exposed. However, you should place a guard rail around the area to keep any child or animal from walking on the surface until it is dry.
- Concrete laid in the open air or in direct sunlight should be covered with burlap, roofing felt or building paper during the curing period. Remove this protective covering before wetting the concrete.
- Never attempt a big concrete job on an extremely hot day. Concrete sets extremely fast in direct sunshine. It's better to wait until mid-afternoon–even if this means you must work late into the evening.
- You can improve the looks of the concrete and make it last longer by sealing the concrete after it has thoroughly cured. Sealers can either be clear or colored. Some coatings have an additive that provides better traction on the concrete surface. Be careful when choosing the coatings and sealers. Some are extremely slippery when wet and should not be used outside.
|
|
TOOL AND MATERIAL CHECKLIST
- Concrete Mix
- Level
- Hatchet
- Grover
- Line
- Concrete Hoe
- 2x4s and Other Material for Forms
- Rubber Boots
- Reinforcing Mesh
- Garden Hose
- Darby or Float
- Tiling Spade
- Long 2x4s for Screed
- Brush or Broom
- Plastic or Galvanized Pail
- Edger
- Line Level
- Trowel
How to Lay Concrete Blocks
|
SELECT THE RIGHT BLOCKS FOR THE JOB
- This figure shows a few of the many types of concrete blocks available for modern construction. Select the correct block for your job before starting the project. Your retailer will be glad to help you select the correct blocks if you need further direction.
- All 8" blocks–the standard unit–are actually 7-5/8" in width. This allows for the thickness of the mortar on the finished job.
- The standard unit is suitable for most projects. Half-blocks with square or rounded corners are often necessary at the end of a run.
- Both single and double corner units provide a block that gives a smooth finish at the corner.
- Jamb joist blocks are used around doorways.
- Sash units provide an opening for casement windows, while header blocks are designed to provide a space for wooden supports or other structures at the top of a wall.
- Other special blocks are available for almost any building requirement.
|
|
|
|
POURING THE FOOTING FOR A BLOCK WALL
- Every block wall–regardless of height or length–should be placed on a secure footing of poured concrete. A block barbecue grill or outdoor fireplace requires a large concrete pad as a footing.
- The footing should always be poured deep enough so that the base is below the frost line.
- Always make the footing at least twice as deep as the thickness of the wall and twice as wide. For example, if you are using 8" blocks, the footing should be at least 8" deep and about 16" wide. This footing will provide a 4" rim on each side of the block when laid.
- The form for such footings can be made from rough 2x4s, held in place by wooden stakes driven into the ground about every 3' to 4'.
- For a footing poured in an area where drainage is a problem, lay a drain line along the outer edge of the form. Allow for a drop of about 1" for each 20' of drain line. Backfill over the drain line with about 12" of crushed stone or gravel.
- Before you pour the footing, be sure it will not prevent the natural run-off of water and will not divert the flow of water onto any neighboring property.
- If gas, electric or water supply lines must pass through the footing, you must make an opening. Do this by nailing together four pieces of 2x8 and laying them in the proper position before the footing is poured. In many cases, a 4" piece of drain tile will serve the same purpose. Mark the depth and location of the utility opening on your foundation plan or with a stake so you can find it easily later on.
- For large concrete foundation jobs that cannot be finished with one pouring, divide the forms into sections you can handle. Complete one before proceeding to the next.
- Make sure your footing is level by placing a level across the footings about every 8'. Adjust the height of the 2x4s by raising or lowering the stakes to make the 2x4s level on each side at all points around the footing.
- Fill the form to the top edge, then level the freshly poured concrete by pulling a 2x4 or some other straightedge along the top of the form.
- Work the straightedge back and forth–in a sawing motion–until the concrete is level. Fill in any low spots with additional concrete. Wipe away surplus concrete in the high spots.
- Allow ample time for the concrete to dry fully. If the footing is to carry an extremely heavy load, drying may require up to three days.
|
|
|
|
ESTIMATING BLOCKS AND MORTAR NEEDED
- Figure provides a table that will help you estimate the number of blocks and the amount of mortar you'll need for your job.
| Use this table to help you estimate the number of blocks and mortar needed for your project. |
Number of Concrete Blocks Required for Each Sq. Ft. of Wall
Based on 3/8" Mortar Joint |
| BLOCK SIZE |
BLOCKS PER 100 SQ. FT. OF WALL AREA |
| 4 X 4 X 16 |
225 |
| 6 X 4 X 16 |
225 |
| 8 X 4 X 16 |
225 |
| 4 X 8 X 16 |
112-1/2 |
| 6 X 8 X 16 |
112-1/2 |
| 8 X 8 X 16 |
112-1/2 |
| 12 X 8 X 16 |
112-1/2 |
| Mortar Needed for Concrete Blocks |
| BLOCK SIZE |
PER 100 SQ. FT. OF WALL AREA |
PER 100 BLOCKS |
| 4" Blocks |
13-1/2 Cu. Ft |
6 Cu. Ft. |
| 8" Blocks |
8-1/2 Cu. Ft. |
7-1/2 Cu. Ft. |
- Select the block size you will be using in the left-hand column. The right-hand column will show you the number of blocks and the amount of mortar required for the job.
- You can also estimate for the number of blocks required by allowing three 8" blocks for every 4' on each course of blocks.
|
|
|
PREPARING TO LAY THE CONCRETE BLOCKS
- Before starting to lay the blocks, drive stakes into the ground and build a form at each corner. These stakes and forms can be made from scrap pieces of wood used on the job.
- Locate the exact corner by stretching lines from one corner form to the other as illustrated. The exact corner will be the point at which the two lines cross.
- Drop a plumb bob down from each line, both at the corner point where the lines cross and at positions about 2' out in each direction.
- Determine the exact number of blocks required for the first course by laying out a course of block on the dry concrete. Do not use mortar for this test run–you are merely determining the number of blocks required for the job.
- Be sure to use the corner blocks where needed, and cut blocks as required.
- Use scrap pieces of 3/8" plywood to fill in the mortar joint between each block. This is the thickness of the mortar when applied.
- After this test run, remove the blocks and prepare for the actual laying of the first course.
|
|
|
|
LAYING THE CONCRETE BLOCKS
- Drop plumb bobs down from the corner string and at positions about 3' out from the corner. Mark the location of the corner block on the footing base as shown.
- Spread the mortar out about 1" deep and 8" wide in the marked area. Extend this mortar out for a distance of about three or four blocks in one direction.
- Put a furrow in the center of the mortar with a trowel. This furrow will force the mortar to the edge of the block when it is laid.
- Set the corner block first. Be sure you are using the correct block (finished end).
- Check the starting corner block, both horizontally and vertically, and take time to get it positioned correctly. All other blocks will align with this starter block, so it's very important to set it exactly.
- Follow this same procedure as you reach the other corners, laying the first course out about two or three blocks in each direction.
- Tie a line between two bricks and stretch it between the two corner blocks on the first course.
- Continue to lay the base mortar on the footing as the course continues. Apply mortar to the ends of the blocks with a trowel and place the block in position.
- Keep all mortar joints at about 3/8". If necessary to make spacing adjustments, fill some mortar joints 1/2" to 3/4".
- If you must cut a block to fill a course, use a masonry chisel as illustrated. Draw a line on both sides of the block where the cut is to be made. Strike the chisel with a bricklayer's hammer. You will soon learn to make such cuts easily.
- After you've laid four or five blocks, use a long mason's level or some type of straightedge to check the alignment of the blocks. Check both the tops of the blocks and the outside edge for correct alignment.
- Tap the blocks into position to make any alignment corrections while the mortar is still wet. Never attempt to move a block after the concrete begins to set.
- Build up the corners first. Always keep the corners about a block or two higher than other runs until you finish the job.
- Keep the guidelines between the corners at all times. They will help you keep the blocks level at all points in each course. Be careful not to knock the lines out of alignment.
- Always keep the guidelines tight. If one side gets bumped out of position, take a minute to level it.
- Use a trowel to cut away any surplus mortar. Throw the surplus mortar back onto the mortarboard. Keep turning the mortar with your trowel throughout the project so small portions will not harden.
- Use a piece of 3/4" ply-board or the bed of a wheelbarrow as a mortarboard. Always wet the board or the wheelbarrow bed before placing the mortar in it.
- Never mix more mortar than you can use in about an hour and a half or two hours. On a hot day, keep the mortar covered with a piece of plastic to hold in moisture.
- Use as much water as the mortar will take and still remain elastic.
- Continue to stagger the blocks–working from the corners–and build the wall to the desired height.
- Take time to level each course. Use a level that is at least 3' long.
- Lay all blocks with the thicker end of the face shell up.
- Keep a leveling string at the top of each course on each run of block.
- Measure both the length and the height of the wall after every two or three runs. Also, hold your level diagonally along the block corners to check for accuracy. If the blocks are being laid accurately, the corners will strike evenly along a level held in this position.
- After all the blocks are laid and while the mortar can still be pressed with the fingers, take a jointer and finish the mortar joints to the appearance desired. Keep the jointer wet during this part of the job.
- You may need to add reinforcing rods to walls built extremely high or in areas where ground pressures may vary.
- Lay 1/4" reinforcing rods as illustrated, with the ends overlapped 2" to 3". Mortar can be placed directly over the rods.
- If wood framing will be attached to the top run, set an anchor bolt every 3' to 4' in the last run.
- If a load-bearing wall intersects with the outside wall, it should be tied to the main wall with metal tie bars. Bars as shown should be set in place on at least every other run.
- Non-load-bearing walls connecting to main walls can be tied in by laying a 16" strip of 1/2" mesh galvanized hardware cloth directly on top of the block.
- A strip of this cloth should be used for every other course at the tie-in point.
- If the concrete blocks are being laid as a fence or barrier, the top course can be finished off by filling in the holes with fresh concrete mix and a trowel.
- For a neater and more enduring finish, use patio blocks for an attractive and weatherproof finish.
|
|
|
TOOL AND MATERIAL CHECKLIST
- Concrete Blocks
- Trowel
- Garden Hose
- 3/8" Plywood
- Drain Tile
- 5/8" Plywood
- Carpenter's Square
- Work Gloves
- Galvanized or Plastic Pail
- Plumb Bob
- Jointer
- Level
- Wheelbarrow
- 100' of Cord
- Anchor Bolts
- 1/2" Galvanized Hardware Cloth
- Mortar
- Masonry Chisel
- Mortar Hoe
- 2x4s for Framing
- Tie-in Bars
- Mortar Board
Building a Foundation
This section is not meant to provide you with the necessary instructions to pour your garage foundation slab. This is not because it is beyond the abilities of the novice builder, although many do contract out this job. Pouring a slab is within most people's abilities. However, unlike wood framing, which can be corrected if improperly constructed, your work on the slab is "set in stone" ...literally. Because of this and the fact that so many local codes and practices apply to concrete slabs, we have only touched on the subject. Should you decide to undertake this project, we suggest you talk with local professionals to be sure you know what you are doing. Have a professional inspect the forms before the concrete is poured and hire a professional to work with you during the concrete pour, as you must be sure to get everything right the first time. A slab foundation is made by building wooden forms and pouring the concrete into these forms. A footing trench is dug around the perimeter to provide added thickness along the edge of the slab which would otherwise be stress areas and the weakest point. Sand or gravel is spread below where the concrete is poured. This is so the under-slab area will not compact under the weight of the concrete and cause the slab to sink. A visquine vapor barrier is installed above the sand or gravel (in some areas below) to stop moisture from traveling up into the slab through capillary action. Wire mesh is placed in the center of the slab and rebar (steel rods) in the footing areas to add rigidity to the concrete to prevent cracking. Local code will dictate such things as thickness of the slab, thickness of the footing, width of the footing, sizing of the wire mesh, thickness of the layer of gravel or sand, size and location of rebar and location of bolts or foundation anchors. Metal foundation anchors or anchor bolts are embedded in the fresh concrete to secure the garage walls to the foundation. Many garage slabs also have a center drain for car or boat washing. Sill (Bottom) Plates  Most Common Mistakes: - Not checking to see if the slab foundation is square.
- Using badly bowed stock.
- Not leveling sill plates.
- Not cutting the top plate so that it breaks at the center of a stud.
The sill plates for a garage are usually 2" x 4" pressure treated or redwood horizontal framing members that are bolted or attached by foundation anchors or anchor bolts to the foundation (or concrete slab). These are also the sole or bottom plates of the stud garage wall. The purpose of the sill plate is to anchor the garage framing to the foundation, to level the foundation wall and to keep the untreated framing members out of contact with the concrete where standing water could cause them to rot. The metal foundation anchors or anchor bolts will have been encased in and should be protruding from the foundation after the concrete was poured. These devices will anchor the sill plate (bottom plate), and thereby the wall, to the foundation. Local code* will specify placement of sill anchors or bolts. Usually foundation anchors should be embedded a minimum of 6" into the concrete with the Bend Anchors over Bottom Plate and Nail Secure upper position split into 5/8" wide tabs which will strap over the 2" x 4" sill plates. These upper tabs have holes to accommodate special fastener nails 1 and 1/4 inch in length. Two nails are driven into each side of the sill plate through the holes in the tabs. The upper ends of the tab are then bent over the plate and nailed into the top of the sill with a minimum of one nail on each side. Choose the order in which you will build your walls. We suggest you begin with a wall that has no windows or doors, if possible.  Select your sill plate stock so that it is as straight as possible. When ordering, specify good straight plate stock 12" to 14" long. If it is longer than this, it is likely to have some warp or bow. If the walls are longer than 14 feet you will want to use more than one piece of stock. When doing so, we find these guidelines to produce the best results. - Do not use pieces under 6' in length if possible.
- Bottom plate splices may be anywhere but top plate splices may only occur in the center of a stud to ensure the strength of the top plate.
- Splices in top and bottom plates must be separated by a minimum of 4 feet on the horizontal and splices in the cap plate (the uppermost of the two top plates) must be at least 4 feet from any splice in the top plate. Before you choose your sill or bottom plates, check code to see if redwood or pressure treated stock is required or preferred. Place them with your wall top plates to do the wall layout. The entire wall is built first, then lifted into place before the sill plates are attached to the slab.
- The total length of each plate equals the total outside length of the walls less 3 and 1/2 inches (the allowance for walls overlapping at the corners). The end of one wall stops at the end of the platform on one side while the other end of the wall stops short by 3 1/2' and is overlapped by the intersecting wall which goes to the end of the platform.
Repair and Care
Concrete is an extremely strong, durable material made from cement and aggregate. Concrete is porous, whether used as a floor in garage, porch or patio, driveway or walks. Often porch or patio floors will have an extra smooth surface, but it will still absorb stains easily. It may be sealed or painted. Concrete floors are sealed to prevent staining, since without sealing they absorb stains readily. The floor must cure and dry after it is laid before it can be sealed, with the time required varying with weather, temperature, building conditions, etc. Floors must be clean, and any remaining alkali in the concrete must be neutralized before sealing. Contact a good paint store or cement dealer for complete instructions and materials to use.
Painting concrete varies depending on its use. Latex floor paints react with rubber tires in garages, as well as with bicycle tires, lawnmower tires, etc. The result is peeling. Alkyd floor enamels are more moisture resistant, and normally old up better under these conditions. But they are more slippery when wet. If there is moisture rising from beneath the surface of the floor, it may also cause enamel floor paint to peel. To clean, wet with clear water. Apply a hot solution of 2 to 2 1/2 ounces washing soda or 1/2 ounce TSP (tri-sodium phosphate) per gallon of water. TSP can be found in paint, hardware and home center stores. Grease Stains: In a garage, it is advisable to place a shallow metal pan under the car to catch dripping oil. Spreading the area under the car with sand or sawdust will help absorb dripping oil. Periodically saturated sand or sawdust should be scraped away and fresh, clean material put in place. This will prevent tracking oil to other areas of cement or into the house. If oil or grease is spilled on porch or patio cement, apply an absorbent powder such as fuller's earth, cornmeal, or sawdust to absorb as much oil as possible immediately. Leave it on stain for a few hours and sweep up.
Here are some various methods to remove grease stains: - Using a stiff long handled brush, scrub stain with concentrated detergent suds. Rinse well with hose. Dry and repeat if necessary.
- Sprinkle "dishwasher" detergent (dry) on wet concrete. Let it stand a few minutes; pour boiling water on area. Scrub and rinse. Use rubber gloves on hands.
- Commercial products are available in paint/hardware home centers. Some can also be used on blacktop surfaces.
- On wet oily surface of concrete, sprinkle with tri-sodium phosphate. Allow to stand 15 to 30 minutes, then scrub with stiff brush and hot water. Rinse with clean water.
- Dissolve a cup tri-sodium phosphate in 1 gallon of hot water. Pour over stained cement surface generously and allow to soak 15 to 20 minutes. Scrub vigorously with stiff brush or broom. Rinse off with hose. Repeat if necessary.
- Scrub the concrete with a grease solvent to remove as much as possible of the grease stain. Have good ventilation and avoid spark or flame as solvents are flammable. Naptha, often recommended, can ignite, just from a spark from friction or rubbing.
- Mix 1 part sodium citrate to 6 parts water and 6 parts glycerin and add enough whiting or fuller's earth to make a thick paste. Spread paste on oil or grease stain. Let stand 1 week. Add new paste when it dries. Flush with water after brushing dry paste away. Repeat if necessary.
Rust Stains: Make a paste of 1 part sodium citrate crystals to 6 parts water and enough whiting or fuller's earth to make a paste. Spread paste on rust stains and allow to dry. Scrape off. Rust should be removed. Repeat if necessary.
Concrete Planters
Homeowners have many options to enhance the beauty of their yards, including flower beds, bird baths, water fountains or garden paths. However, a simple and affordable feature often overlooked are flower planters. The appropriate placement of planters filled with colorful and fragrant flowers can dramatically improve the appearance of a yard. While flower planters come in various sizes, shapes and materials, homeowners can realize savings and personal satisfaction in creating concrete planters. An easy do-it-yourself project, concrete planters can cost a fraction of purchasing a flower planter from a retail center and allows homeowners to personalize the appearance of their yards. To create a concrete planter, do-it-yourselfers will need concrete mix, sand mix, 3/4-inch plywood, 1/4-inch plywood, hammer, nails, one inch plastic pipe, a tamper, a trowel and form oil or paste wax. Once the materials are gathered, the following are step-by-step instructions: - Use 3/4-inch plywood and 1/4-inch plywood to build an outer form with inner dimensions of 18-inches long by 15-inches wide by 10-inches high. Use the 3/4-inch plywood for the sides of the form and the 1/4-inch plywood for the bottom of the form. Nail the forms sparingly for ease in disassembly when removing the completed concrete planter.
- Build an inner form with outer dimensions of 14-inches long by 11-inches wide by 8-inches high for use with outer form to create concrete planter with 2-inch thick walls and bottom.
- Coat the forms with form oil or paste wax to make removal from the form easier.
- Prepare the concrete mix using instructions on the package and cast the planter starting with a 2-inch base layer. While laying this base layer insert the plastic pipes to create drain holes. The pipes should be centered along the width of the planter and in thirds along the length of the planter. Smooth the concrete to the height of the pipes.
- Center the inner form and press it down over the smoothed concrete, continuing to pour the concrete around the edges of the mold. Use a tamper to compact the concrete around the form during pouring. Smooth the exposed surface with a trowel and keep damp.
- Remove the forms after 24 hours and continue to keep the concrete damp for five to seven days before planting.
- Clean the form parts immediately following removal and set aside for future use.
A new yard at the old address is easy when you create a concrete planter.
Masonry Anchors
Masonry anchors have come a long way since the days of lead and zinc anchors. It used to be that fastening anything to concrete was a major chore, but advances in materials and design have made anchoring to concrete–well, if not easy, at least within the reach of a handy do-it-yourselfer with an average set of tools. Inside this document you will find information about:
| HOW MASONRY ANCHORS WORK
- There are three basic types of masonry anchors: 1) mechanical, 2) powder-actuated and 3) chemical. It's unlikely that you'll need a chemical anchor unless you're building a bridge, and in many states, certification is required to use powder-actuated fasteners. This document describes how to use mechanical anchors.
- Products do vary from one manufacturer to the next; if the manufacturer's installation instructions are different than the information in this document, always follow the manufacturer's instructions. One caution when installing masonry anchors–always wear eye protection and follow the manufacturer's safety instructions.
- Most masonry anchors work in one of two ways–either by expanding against the sides of the hole and gripping the concrete or by friction against the sides of the hole. The holding power of any anchor depends on the quality of the concrete and on where the anchor is placed. If the concrete is old and crumbly, the holding power of the fastener will be reduced.
- Likewise, if the anchor is placed near the edge of the concrete–or two anchors are placed too close together–the force generated by the anchor may break the concrete. The general recommendation is that any anchor should be placed no closer than five diameters from the edge of the concrete. In other words, a 1/2" diameter anchor should be no closer than 2-1/2" (1/2" x 5) from the edge of the concrete.
- Two anchors should never be placed closer than 10 diameters from each other. In other words, two 1/2" anchors should be at least 5" (1/2" x 10) apart.
- The most important factor in choosing the proper anchor is the type of load it will carry. An anchor is rated for two types of loads. Shear loads are caused when the weight of the fixture exerts force parallel to the surface of the concrete. Tensile loads are caused when the fixture exerts force perpendicular to the surface.
- Naturally, a load may exert a combination of the two. An anchor that carries a pipe hung from the ceiling is under a tensile load, while a mirror hanging from a basement wall exerts almost a purely shear load. A shelf hung from the same wall exerts a combination of the two forces, as does a floor-mounted anchor that holds a table saw in place in the garage.
- Other load factors are also important. They include:
- Static loads are loads that are steady and constant–for example, the weight of the circuit breaker box fastened to your basement wall. They place the least stress on the anchors.
- Dynamic or vibrating loads are loads that are constantly changing. For example, if you hang a shelf from a concrete wall in order to mount your electric grinder, the load on the anchors will be a dynamic load. The strength rating of the anchors will be reduced by the constant vibration of the load.
- Impact loads are loads that change suddenly–such as a box tossed onto a shelf anchored to the basement wall.
- Because of the inexact quality of concrete, the standard recommendation is that the anchor you choose should be rated for about four times the weight it will carry if it will bear a static load and eight times the weight if it will carry a dynamic or impact load.
|
|
| USING MASONRY ANCHORS
- When choosing anchors, remember that the total load should be divided by the number of anchors that will carry it.
- Whatever type of anchor you decide to use, you'll probably want to rent a hammer drill to drill the holes for it. Masonry drill bits work by chipping concrete away (as opposed to wood bits, which cut wood away). If you use a standard electric drill, you'll find that it not only drills much more slowly, but you'll be much more likely to ream the sides of the hole and wind up with a hole much larger than you intended.
- The holes have to be exact in diameter and sometimes even an exact depth in order for the anchor to work properly. Some manufacturers' anchors must be installed with special drill bits. For best results with masonry anchors, it is important to "blow out" any excess dust from the drilled holes. One of the easiest ways to do this is with a kitchen blaster.
- This document covers four basic types of masonry anchors: 1) concrete screws, 2) hammer anchors, 3) one-piece expansion anchors and 4) two-step expansion anchors that are used with standard screws.
- They are called "two-step" because the holes must be spotted before installation. In other words, the anchor is larger than the fastener that will go into it. As a result, you'll have to position the material to be anchored and spot the locations of the holes, then set the material aside so you can drill holes and insert the anchors. Finally, you can place the material in position again and fasten it down.
- One advantage to these anchors is that the screws can be removed and reinserted. Also, they are relatively inexpensive.
- If you're using lag shields, you'll have a choice between short or long shields. Use the short shields in hard masonry (usually older concrete) or the long shields in softer masonry. Long shields are generally about 30 percent stronger than short shields, but drilling through old, hard concrete is not an easy task.
- To install a two-step anchor, drill a hole the specified diameter and depth (usually slightly deeper than the length of the anchor). You can mark the depth on your drill bit by measuring the length of the anchor, then wrapping a piece of tape around the bit at that point. Insert the anchor, tapping it lightly with a hammer to seat it. Position the material, then drive the screw into the anchor until it is snug. Do not over-tighten the screw.
- One-Piece Expansion Anchors– Two-step anchors have become a thing of the past with professional builders, however. One-piece expansion anchors not only require no hole-spotting, but, since they are steel, they provide a much stronger grip than plastic or lead anchors.
- Two types of one-piece anchors are popular. Sleeve anchors have a steel sleeve on the shank, split at the bottom so it can expand. The bolt has a cone-shaped plug at the base, and a nut on the top. When you place the anchor in the hole and tighten the nut, it draws the bolt upward, pulling the plug into the sleeve and expanding it against the hole.
- Once installed, sleeve anchors cannot be removed. They do come with a variety of heads, however–a removable hex head, an acorn nut, or either round- or flat-head screws.
- The shank of a wedge anchor is similar to a sleeve anchor–a solid shank, threaded at the top and with a cone-shaped plug at the bottom. But the shank of a wedge anchor is grooved on opposite sides. In each groove is a rectangular shank with a spade-shaped wedge on the end. As the nut on top is tightened, the washer pushes the rectangular shanks down, which spreads the wedges over the plug.
- Like a sleeve anchor, a wedge anchor cannot be removed once it is installed. Wedge anchors always have a hex head with a washer so the material can be removed and reinstalled.
- To install wedge or sleeve anchors, first position the material you want to anchor. Drill a hole in the masonry behind the bolt holes. Make sure the hole is the specified diameter, at least 1/4" deeper than the length of the anchor. Insert the anchor in the hole. Tighten a sleeve anchor two to three turns to expand it. Tighten a wedge anchor three to five turns. Manufacturers' instructions may specify that the anchor is tightened with a torque wrench to a certain number of foot-pounds.
- As a rule, use sleeve anchors when you're working with soft concrete or installing them in the mortar joints between block or brick. Also use sleeve anchors when you suspect that the concrete may have voids in it. Sleeve anchors have a larger bearing surface than wedge anchors.
- Use wedge anchors for maximum holding power in hard concrete.
- Hammer Anchors– For lightweight applications such as hanging furring strips or conduit, a hammer anchor is an excellent alternative to a plastic or fiber anchor. There are a number of styles.
- The most common consists of a hardened steel ring-shank nail with either a nylon or zinc sleeve over the shank. Like one-step expansion anchors, hammer anchors require no hole-spotting.
- To install a sleeve-type hammer anchor, simply drill a hole through the material you're anchoring, large enough to accept the sleeve but small enough that the sleeve flange won't slip through. A newer type of hammer anchor looks like a heavy nail with a short bend near the end of the shank.
- To install either type of hammer anchor, set the material in position and then drill the masonry behind it. Be sure to use the size drill bit specified by the manufacturer. The hole can be any depth as long as it is deeper than the length of the anchor.
- Insert the anchor through the material and into the hole, and drive it down tight with a hammer. Hammer anchors obviously don't have the strength of larger expansion anchors, but while they aren't meant to be removed, you can pry them out if necessary.
- Concrete Screws– Concrete screws came onto the market in the mid-1970s and have become a staple of lightweight applications. They look like any other screw, except that they are made of hardened steel that will cut its own thread in the masonry.
- To install them, set the material in position and then drill the masonry behind it. Be sure to use the size drill bit specified by the manufacturer–concrete screws require a precise pilot hole with a slightly smaller diameter than the screw. The hole can be any depth as long as it is deeper than the length of the anchor.
- The big advantage of concrete screws over hammer anchors is that the screw can be removed and then reinstalled. You will lose some holding power if you do so, however.
- There are no hard and fast rules about which anchor to use in what situation, but the following guidelines will help:
- Machinery to a concrete floor–As a rule, you'll want to use a heavy expansion anchor such as a sleeve or wedge anchor.
- 2" x 4" sleeper over a concrete floor– Powder-actuated fasteners (PAFs) are the most common because they are fast. If you're not certified for PAFs and only laying a small area, use hammer anchors.
- 2" x 4" framing around a door or window opening–Use hammer anchors.
- Furring strips on a foundation wall– Again, most builders use powder-actuated fasteners for the speed. If you're not certified for PAFs, use hammer anchors or concrete screws.
- Shelf brackets on a foundation wall–Concrete screws are generally the best choice because they can be removed if necessary.
- A deck ledger on a masonry wall–Use edge anchors on concrete or sleeve anchors into the horizontal mortar joints of a brick or block wall.
- Conduit to a foundation wall–Use either hammer anchors or concrete screws.
- Mudsill to foundation–Use a sleeve anchor as a substitute for an occasional missing anchor bolt. If you're starting from scratch and there are no bolts, use either sleeve anchors or wedge anchors.
|
|
TOOL AND MATERIAL CHECKLIST
- Steel Measuring Tape
- Hammer Drill
- Screwdriver
- Hammer
- Masonry Drill Bits
How to Patch Concrete
|
REPAIRING HAIRLINE CRACKS
- You can repair hairline cracks in concrete with a grout made of Portland cement and water. Add just enough water to the cement to form a thick paste.
- Moisten the old concrete along the hairline crack with water for several hours before adding the grout. Moistening the concrete prevents it from drawing the water from the grout, which will dry out the mixture. Although the old concrete should be moist, no water should be standing on the surface when the grout is applied.
- After the hairline crack has been moistened and thoroughly cleaned, apply the grout with a putty knife or pointing trowel. Force the grout into the crack as much as possible. Then smooth it off so it is level with the original concrete.
- Allow the patched area to dry about two hours. Then, cover the area with a piece of plastic sheeting or a board.
- Keep the area covered for about five days. Lift the covering once each day and sprinkle the area with water.
|
|
REPAIRING CRACKS IN SIDEWALKS
- Cracks in sidewalks that are larger than hairline cracks must be enlarged before they can be satisfactorily repaired. Enlarge the crack along its entire length with a cold chisel and hammer.
- Make the crack wider at the bottom than at the top. This is known as undercutting. It helps to bond the new concrete with the older concrete.
- Undercut the crack to a minimum depth of 1". The depth of the undercutting depends on the size and depth of the crack to be repaired.
- After the crack has been thoroughly undercut, remove all loose material and brush the area with a wire brush.
- Use a garden hose or a tire pump to blow or wash away the dust in the crack.
- The new concrete patch will hold better if a concrete adhesive is used first. There are many types of concrete adhesives. Acrylic resin–a milky fluid–is one common type. Brush the adhesive into the undercut area and allow it to dry until it becomes tacky.
- If you do not use a cement adhesive, thoroughly brush and soak the area to be patched. Moistening the area prevents the old concrete from absorbing all the moisture in the concrete patch. Although it should be moist, no water should be standing on the area where the patch is to be applied.
- For small patching jobs, use a pre-mixed concrete patch. If you use ready-mix concrete patch, all you need to add is water.
- If you mix your own concrete patch, use one part Portland cement to two-and-a-half parts of fine, clean sand. Heavier concrete patch jobs call for one part of Portland cement to two parts of sand to three parts of gravel.
- Tamp the concrete patch mix tightly into the undercut area. Be sure to fill all areas completely.
- When the mixture begins to set, smooth it down with either a metal trowel or a wooden float. Use a metal trowel for a smooth finish. For a rough surface, use a wood float for the finishing job.
- After the patch is completed, allow it to dry for about two hours. Then cover the patched area completely with plastic sheeting or boards.
- Keep the area covered for about five days. Lift the cover once each day to wet down the repaired area, permitting the new concrete to cure correctly.
|
|
|
REPAIRING CONCRETE DRIVEWAYS
- You can repair a crack in a concrete driveway in basically the same way as a crack in a concrete sidewalk. However, since the driveway must carry heavier weight loads, the repaired area must withstand much greater pressure.
- Use a gravel mix, rather than a sand mix, for repairing concrete driveways. This mix is one part Portland cement, two parts sand and three parts gravel.
- Thoroughly clean and then undercut the crack. Brush cement adhesive into the undercut area.
- Undercut the cracked area to a greater depth and make the cracks considerably wider than when repairing a sidewalk. This extra depth and width increases the strength of the repair job.
- Follow all of the steps outlined previously in repairing a crack in a sidewalk to repair a crack in a concrete driveway.
- After the gravel mix has been applied, level the new patch mix off with a trowel or float, as you would do when repairing a sidewalk.
- Cover the patched area for five days, wetting it down once each day.
- Do not drive an automobile over the patched area for at least five days. This gives the newly patched section time to dry thoroughly before it must carry the heavy load of an automobile or truck.
|
|
|
REPAIRING CRACKS AND HOLES IN CONCRETE WALLS
- Repairing a crack in a concrete wall requires basically the same steps as repairing a crack in a sidewalk or driveway.
- The cracked area must first be undercut and widened in basically the same way as previously described for a sidewalk.
- The widening and undercutting can be done with a cold chisel and hammer. The width and depth of the undercutting depends on the size and length of the crack.
- After all loose material has been chipped away, thoroughly clean the undercut area around the crack with a stiff wire brush. Do not brush the area enough to smooth off the edges. The rough surface created by the chiseling provides a good bond for the new concrete you'll apply.
- When the enlarged area has been thoroughly cleaned, apply cement adhesive with a brush. This is the same cement adhesive used when repairing sidewalks. If you do not have a cement adhesive, prime the area with a thin, creamy mixture of Portland cement and water.
- In some cases, you can make the patch by simply moistening the area thoroughly before filling the crack with concrete. Although the moistening is important, a concrete adhesive or the mixture of Portland cement and water is much more desirable than moistening with water only.
- You can use a ready-mix concrete patch for small cracks in cement walls. Force the mixture into the cutaway area with a pointing trowel. Be sure to use enough pressure to force the patch mix into all the cutaway areas in the crack.
- It may be difficult to conceal the patch, since the finish on the old concrete is difficult to duplicate. To conceal the patch, simply experiment with matching the original finish by roughing up the patched area while it is still workable. Try using an old broom, a float, or any other tool to create the desired rough finish.
- You can patch holes and broken areas in concrete walls by simply clearing out the hole in the same basic way you would undercut a crack.
- After the hole has been thoroughly cleaned and cut away, apply the cement adhesive and insert the patch mix into the hole with a pointing trowel.
- Moisten the area and cure it after the patch is applied in the same way cracks in cement driveways or sidewalks are moistened and cured.
|
|
|
PATCHING HOLES IN WALKS OR DRIVEWAYS
- How you patch holes in sidewalks and driveways depends on the depth and the size of the hole. If the hole is extremely deep and large, you must undercut it as previously described and fill the area with a gravel mix.
- Small, shallow holes in flat-surfaced concrete–such as driveways, patios or sidewalks–can easily be repaired with latex cement. If the hole is small and shallow, no chipping away is required.
- Small, shallow holes need only to be cleaned thoroughly before adding the latex cement.
- This cleaning can usually be done with a wire brush, which removes all the small pieces of loose concrete when you rub the area thoroughly.
- After using the wire brush on the damaged area, use a lighter brush to remove the loose particles that were dislodged by the wire brush. Then, wash the area to be repaired with a garden hose.
- After the cleaning is done, you are ready to apply the latex cement. This usually comes in 5-lb. cans, with the liquid latex in a smaller can inside a larger can.
- Pour the liquid latex into the larger can and thoroughly mix it with the latex cement to form a heavy paste. Apply this paste to the area to be patched in approximately 1/4" layers. Smooth each layer with a trowel and allow to partially dry before applying the next layer.
- Build up the latex cement 1/4" at a time until it reaches the same level as the original concrete. Then, smooth out the area with a trowel or float as you would finish regular concrete.
|
|
|
REPAIRING BROKEN CORNERS ON CONCRETE
- You can repair broken corners on concrete with latex or epoxy cement. A broken corner should be thoroughly cleaned and moistened before the mixture is applied.
- After the corner has been thoroughly brushed and washed, build up the latex or epoxy cement mix 1/4" at a time, as previously described. If the area to be repaired is quite large, you may need to build a small form to hold the mix while it is drying.
|
|
TOOL AND MATERIAL CHECKLIST
- Concrete and Aggregate
- Concrete Float
- Cold Chisel
- Concrete Patch Mix
- Cement
- Hammer
- Finishing Trowel
- Garden Hose
- Work Gloves
- Fiber Brush
- Latex or Epoxy
- Pointing Trowel
- Wire Brush
Repair a Concrete Step
Not only is a flaking, crumbling, or cracked concrete step unsightly, it can also be a dangerous trip hazard. When the combination of years and weather elements begin to take a toll on your concrete steps, you need a way to repair them quickly, safely and economically. Fortunately, this is a project that you can do on your own with too much mess and without a great deal of expense.
If the horizontal surface of your concrete step is flaking or chipping away, then you may just need to resurface it. There are several good products on the market that you can use to accomplish this task. A vinyl concrete patch is perhaps the easiest. This material mixes up easily and, instead of spot patching as you would with regular concrete patch, this material is spread over the larger surface of the step. It flows into the chips and pits left behind by the flaking concrete. This material is thin enough to find its own level, so you just need to spread it around and make sure that it is smooth. As with any masonry work, it is important to make sure that the area is clean of debris, dust, and broken pieces of concrete before you apply it.
Another scenario involves a concrete step where the corner of the step has cracked and broken off, leaving a dangerous and jagged edge. If this is the case, then you will need to build a small form to hold the concrete patch into place. In most instances, this form is easily built using 2x6’s and some screws. Remember, a form doesn’t have to be built to long-term construction standards; it just needs to hold the concrete in place until it sets up. Make sure that your form can be easily disassembled and that you won’t have to damage your new patchwork when you are trying to take it apart.
The best product to use for repairs like this depends on the size of the damage. If the corner or edge that you are repairing is small and no more that 2” deep, then you can use sand mix. Sand mix is a dry mixture of fine sand and Portland cement. It is used to make shallow repairs because it doesn’t have any stone. The lack of stone allows you to float the wet sand mix to a smooth finish that will blend in well with the rest of the step. If the repair that you need to make is deeper than 2”, then you should use a standard ready-mix concrete. This does have stone in it. You need to use this stone mixture on deeper patches because the stone gives additional strength to the concrete after it has dried. If you tried to use the sand mix to patch the deep spots, it would crumble and break away when it became exposed to regular traffic.
A third scenario involves a crack in the middle of the step or walkway. There is no concrete flaking or breaking away, the slab has simply broken in two, and now there is a gap. There are several reasons why you need to fix this quickly.
First, it will just continue to get worse. If you live in a part of the country where you have a seasonal freeze and thaw, then the action of the ground flexing will continue to pull the broken pad apart. Secondly, you need to fix it quickly because this is a serious safety hazard. Whether you have small children or elderly women whose heels may get caught in the crack, a hard fall on concrete can be devastating.
The ideal way to fix this depends on the nature of the crack. If the two pieces are still level with one another, then begin by stuffing a piece of backer rod into the crack. Backer rod is a foam rope that can be purchased at your local home improvement store. When you shove it into the crack, it expands and creates a surface for your patch material to sit on. Without the backer rod, the patch would just flow into the ground underneath the step. Once the backer is in place, use a polyurethane concrete patch to fill the crack. This is rubberized filler that will flex with the seasonal changes and won’t pull away and crack further as a concrete patch would.
If the two pieces are not level, then you need to form a ramp of sorts to smooth the transition from one piece to the other. This difference in height is what will cause most falls. The best way to form this transition is to use backer rod to fill the majority of the crack and then use sand mix like we discussed above. Using a trowel, fill the remainder of the crack with sand mix and then let it dry. After the sand mix in the crack has dried, use a second application to form a transition between the two different heights of concrete. It should be gradual, so that people can slide their feet over it without stubbing a toe or a heel. Remember, the idea is not just to fill the crack, but to make the walking surface safe.
Any tools that you use when working with concrete should be cleaned immediately. Most will clean up quite well just with the garden hose and some fresh water. Any product that you use that requires more than water will give detailed clean up instructions on the package. Remember, it is easier to take a few extra minutes to clean up your tools quickly than it is to try to chip away dried up concrete the next time you want to use them.
|
