Wisconsin Forums

[MrKhay]

GB2,
1. Building concrete patios requires as much planning as do gardens. Buy materials/concrete tools and rent automatic concrete mixer. Concrete calculator: to cover 50 sq. ft., 6 in. thick, you need 25 bags of pre-mixed concrete.

2. Excavate the landscape with a garden shovel. In northern landscaping, 6 in.-- 2 for a bottom layer of gravel and 4 for the concrete. The bottom is for drainage to prevent cracking from your landscaping's freezing-thawing cycle.

3. Build a form to hold the gravel and concrete. Sink form into the excavated patio area. The top of the form should be level with the ground, if you want the patio to be flush with ground level.

4. Install gravel, tamping it down firmly. Install 2 in.-high flat pieces of rock (rid your garden of some rocks!) as supports for rebar reinforcing, which you must build approximately in the middle of the 4 inch thick concrete slab.

5. Install reinforcing rebar to unify the concrete slab. Make a grid by placing them at every two feet both from front to back and from left to right of patio. Unite them with wiring at intersections.

6. Mix concrete in rental automatic mixer, first adding water with a garden hose to the mixer, then concrete, then water again -- until mix becomes a uniform, shiny medium gray.

7. Pour concrete, starting at end farthest from where your mixer is, building a ramp if necessary. Add filler rocks as you go. Pour as fast as possible. Preparation is crucial here.

8. Use a screed (see link below) to level the surface of the concrete, sliding the screed along the top of the form boards. Pull the screed from one end to the other, drawing off excess concrete.

9. Cut initial control joints in patio at about every 3-4 feet with a mason's trowel (not a garden trowel), 2 in. deep. To achieve a straight cut, place a board across your forms at right angles to use as a guide.

10. Look for a watery layer to appear on the surface of your concrete (the concrete is said to "bleed" as it settles). After this watery layer appears, wait for it to disappear before proceeding.

11. Use a float (see link below) to even out any lumps on the patio. Sweep it in an arc-shaped motion, keeping the edge at the front of your sweep slightly raised, lest the float dig into the concrete.

12. Finish the control joints begun in Step 9. Use a jointer (see link below) to make a clean groove, about 1 in. deep (or 1/4 the depth of the total slab). Re-use the same board as a guide.

13. Finish patio surface with design elements. Running a pushbroom over the patio makes a design both attractive and practical: lines that provide visual interest and a slip-resistant surface.

14. Lay plastic over the new patio. Concrete must be "cured" properly. The key to curing is not letting it dry out too fast. By laying plastic over the patio, you trap the moisture within.

15. Keep the plastic on patio for a week. Concrete doesn't fully cure for 3 weeks, so even after you've removed the plastic, don't subject the concrete to undue stress.
Tips:
Avoid skin contact with concrete, as well as inhaling the dust. Make use of gloves, kneeling boards, long pants, long-sleeved shirts, protective boots, goggles, face masks, etc.
In my area, Home Depot rental has a 24-hr. rate for automatic cement mixers that is cheaper than the 10-hr. rate of smaller rental service stores. When in doubt, buy extra concrete. You don't want to find out that you're a bag short just as you're about to put the finishing touches on your masterpiece and the concrete is starting to harden!
If you want to lay brick on the concrete slab and still have patio flush with the ground, dig an extra 2 1/2 in.-- 2 in. for the brick and 1/2 in. for the mortar between the bricks and concrete.
If in your digging you come across any stones, wash them and set them aside to be incorporated into the concrete. They'll take up space and save on concrete usage. It's also a good time to dispose of garden rocks.
If you're digging 6 in., 2x6s make an ideal form. But since their tops will be flush with the ground, prevent debris from falling in on your project by covering the landscaping area with tarps.
What You Need:
"pre-mixed" concrete
automatic cement mixer
gravel, screed, float
four 2x6s, scrap boards
nails, garden shovel
rebar, wire
garden hose
trowel, jointer
protective clothing, mask and goggles
http://landscaping.about.com/cs/hard...rete_patio.htm