Build a Block Garage
Concrete block garages are stronger and more durable than wood framed or steel garages. They can hold up beams. These garages are insect and rodent proof. They rarely fall down or leak in a storm. Because concrete blocks are thick, the garage is more sound proof than other types and can withstand the pressure of a blast or a fire. Constructing a block garage takes more man power--and costs considerably more money--than conventional framing, but the pros far outweigh the cons.
Instructions
1. Layout your area for the garage by placing stakes in the corners. Dig out all the dirt within the area 6 inches deep. Place 2-by-6 form boards around the perimeter.
2. Nail the boards at the corners and place stakes behind them every 3 feet for support. Nail the stakes to the form boards with double headed nails so they are easily removed when you are finished.
3. Dig out your footings 1 foot wide by 18 inches deep around the perimeter. A footing is the structural part of the slab that bares the weight load of the structure above.
4. Place two 1/2 inch rebar horizontally all the way around the bottom of the footings, making sure the rebar is at least 3 inches away from the earth by placing a 3-inch by 3-inch dobey block every 3 feet underneath the rebar. Rebar is a structural steel rod manufactured to be placed in concrete to add strength. Rebar can be purchased at most hardware stores. Dobey blocks are small concrete blocks with tie wire bult into them to space rebar a given distance above the earth.
5. Run a length of two 1/2 inch rebar also on the top of the footings, keeping the rebar 3 inches away from earth and air.
6. Attach 1/2 inch rebar rods vertically every 16 inches around the footings 4-inches in from the outside edge.
7. Tie them into the top and bottom of your horizontal rebar with tie wires. Tie wire is a spool of wire made to tie rebar together.
8. Pour 2 inches of sand into the garage slab area and a 6-mil vapor barrier between the sand. Although the vapor barrier isn't mandatory, it is highly advisable. The vapor barrier is a plastic that keeps the concrete slab from sucking moisture out of the earth. Without a vapor barrier your slab can develop a white lime substance coming through and discoloring your slab.
9. Rake the sand flat and lightly moistion the sand to make it harder so it stays flat under pressure. When you place your concrete over the wet sand it doesn't suck the moisture from the concrete, thus weakening the concrete.
10. Lay out your 1/2-inch rebar grid over the sand. A rebar grid is rebar that runs in two different directions adjacent to each other. Use your rebar tie wire and tie the two rebars together at all intersections.
11. Lay 2-inch dobey blocks under the grid where the rebar intersects. These blocks keep the rebar off of the ground preventing possible corrosion. Tie the rebar intersections with tie wire.
12. Pour concrete into the footings and allow it to flow over onto the slab foundation. It will be a monolithic pour, which means it's a single pour; footings and slab done in one pour.
13. Take the measurements from the floor plan and transfer them to the garage slab. Establish a chalk line from one corner to the other on all sides. The face of the blocks will be laid on this line.
14. Spread out 1 inch of thick mortar starting at a corner on the slab. Place it with a trowel around the rebar rods, but not completely covering the full area underneath.
15. Press down your first 16 inch block in place over the rod leaving a 3/8 joint. Make sure the first layer of blocks is laid straight and level. Place all the corner blocks the same way.
16. Layout the lead blocks, which are blocks extending out from the corner blocks, four blocks long.
17.Trowel a vertical bead of mortar on the side of the block already in place and set another block up against it. The mortar creates the joint between blocks. Do the same for all blocks going up.
18. Place the blocks on top of each other staggered, not directly over each other. This creates a stronger wall.
19. Place the blocks over the reinforcing rebar rods as you come to them. When the block gets too high and you run out of rod length, tie in new rebar rods to the existing rods with a 10 inch overlap. Use heavy duty tie wire to connect them.
20. Pump P-gravel concrete into the tops of all the blocks. This is called your grout. You need to pump P-gravel into the block walls every four to six feet. This concrete will flow to the bottom and fill up all the blocks with concrete, giving your garage walls extra strength. P-gravel is a fine gravel 1/8-inch to 1/4-inch in diameter, fine enough to be pumped through a hose.
21. Place the foundation bolts in the tops of your blocks before the concrete dries. A foundation bolt is 5/8-inch by 12-inch and bent at the bottom. It is placed in the concrete so you can bolt down your first sill plate to the wall for giving your wall uplift strength.
Tips Warnings
Cut off all the excess mortar with the edge of the trowel. Any mortar that dries on the block can be brushed off with a bristle brush. Excess mortar can be reused, but do not reuse mortar that falls on the ground.
Cut off all the excess mortar with the edge of the trowel. Any mortar that dries on the block can be brushed off with a bristle brush. Excess mortar can be reused, but do not reuse mortar that falls on the ground.
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