Is It OK To Pour Concrete Over Grass?

Do you need gravel under concrete?

Whether you pour concrete for a walkway or patio, a strong gravel base is required to prevent the concrete from cracking and shifting.

Gravel allows water to drain into the ground below.

When packed tightly, however, the gravel doesn’t shift beneath the concrete..

What happens if it rains after pouring concrete?

Even if it starts raining after a concrete pour, the potential for damage may not be that serious. If you had time to complete the finishing process and the concrete has stiffened (typically 4 to 8 hours after mixing), rainwater may cause little if any damage.

What type of gravel goes under concrete?

Backfill beneath concrete flat-work along foundation walls should be accomplished with a granular material that is uniform in size. Some fill materials, such as round stones like pea gravel, tend to be self compacting. “I recommend open-graded granular material be used,” says Tull.

What do you put under patio slabs?

To get the best results, use sharp sand. It’s perfect for patios and gardens, and will prevent moles or rats from tunnelling underneath the paving slabs.

Can you put concrete over grass?

Cheap and versatile and easy to pour, concrete will last you years down the road. You can pour it just about everywhere—including on the grass. Although it takes a little work, pour concrete over grass to create that walkway you always wanted or that mowing preventative you could previously only dream about.

What do you put down before putting concrete?

To shore up the subsurface, sprinkle a thin layer of cement sand onto the gravel and dampen it with water. Do not leave any standing water and allow the dampened sand to dry for about an hour before pouring the concrete. Ground preparation is key to pouring sidewalk, driveway or any other concrete slab.

How many square feet does an 80lb bag of quikrete do?

60 cubic feet45 cubic feet and an 80-pound bag yields . 60 cubic feet.

How many inches of gravel do you need for a concrete slab?

Excavate the slab area to a depth of about 7 inches, allowing 3 inches for a gravel base and 4 inches for concrete.

What is the best base for a concrete driveway?

The gravel base for a driveway should be a minimum of 4 inches deep. If heavier vehicles, such as large trucks, will use the driveway regularly, the gravel should be even deeper, up to 12 inches. Poor soil or a sloped driveway may also require deeper gravel.

Can you pour concrete over mulch?

If you make the mulch deep enough and check the condition of the concrete after each winter, you should be fine.

How long should concrete set before removing forms?

The forms or “molding” that holds the concrete in place until it dries should be left alone for at least two days to ensure that the concrete is completely dry. If the forms are removed too soon, the concrete can begin to sag, crack and collapse, especially if conditions like temperature affected its strength.

Should you put plastic under concrete?

Recently, though, research has shown that the old traditional layer of 6-mil Visqueen (polyethylene plastic) under the slab is seldom effective for two main reasons: Although it may seem water-tight, this grade of material allows a lot of water vapor to pass through.

Can you lay concrete slabs on grass?

Generally you do not lay paving slabs directly on grass if you want them to last and look good for any length of time.

Do you need rebar for 4 inch slab?

No, depending on your proposed loads. But a 4″ thick slab really shouldn’t have rebar in it, too thin. Most thing slabs, like driveways or sidewalks have a wire mesh reinforcement in them not rebar. … If your slab is going to be subjected to enough load to need rebar it will also need to be thicker; 6″ or 8″.

Why do you put stone under concrete?

Because concrete is a very porous material, it will absorb any moisture that it contacts. This can cause pooling. Without crushed stone, pooling water will settle under it and erode your slab. Adding a layer of crushed stone will add proper drainage, as well as create a barrier between your slab and the ground.