DIY: Footings on a Sloped Grade
Warning
Why Level Footings Are Essential If the footing isn’t absolutely dead level, the wall will be out of plumb. It’s so common that some installers automatically plan on installing the vertical rebar with a hammer drill a few days after the footing is poured. Others will wet-set the rebar before the concrete hardens.
How do you pour a concrete slab on unlevel ground?
How to Form a Concrete Slab on Unlevel Ground
Does the ground have to be level to pour concrete?
The ground should be dug to a depth of 3 to 5 inches with a trench dug on either side. If the ground is mostly clay, an additional 2 inches of depth is needed to hold gravel, which will aid in drainage. If the surface is prepared with a fluctuation in depth of no more than 1 inch, your concrete will be level.
Can you lay concrete on uneven ground?
Concrete Slab on Sloped Ground When building a level concrete slab on a slope, you have a few options. Fine Homebuilding recommends a concrete with low slump. Mark off the area as usual and then dig it out to the required depth. The depth depends on what type of concrete you’re using and whether it needs a gravel base.
How do you prepare the ground before pouring concrete?
Preparation is the most important aspect of pouring a concrete slab.
Do you need gravel under concrete?
You do need gravel under a concrete slab, footing, or patio. Gravel provides a solid foundation for your concrete as it can be compacted. It also improves drainage, preventing water from pooling beneath the concrete.
Do you need rebar for 4 inch slab?
No, you do not need rebar for a 4-inch slab of concrete on grade. A 4-inch-thick slab cast on the ground and in permanent contact with it will float and rebar is not required. Rebar is recommended on concrete measuring 5 – 6 inches thick.
What is the best fill under concrete?
The top 6 to 12 inches of the backfill under the slab should be filled and compacted with well-graded gravel or crushed material. “Walls are typically backfilled with the removed earth or with a granular, open-graded material,” says Tull.
Should you put plastic under concrete?
A concrete vapor barrier is any material that prevents moisture from entering a concrete slab. Vapor barriers are used because while fresh concrete is poured wet, it’s not supposed to stay that way. It needs to dry and then stay dry to avoid flooring problems. This is why a vapor barrier under concrete is essential.
Is sand a good base for concrete?
Pour concrete over a solid, well-drained base of sand or gravel over clay and other poorly draining soils to provide even support.
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.
Why do you put 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 is especially important in clay soil because it doesn’t drain well, which results in water pooling under the concrete slab and slowly eroding the soil as it finally drains.
Can you have too much gravel under concrete?
Any more depth of gravel is ok with the proviso that it be well compacted. That means putting it down in thin layers and compacting the *&$%$# out it each time. When you are ready to pour your slab after a couple years check the grade and maybe put in a little more gravel if you need it.
How long should concrete cure 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 wet concrete while curing?
ANSWER: Keeping concrete moist helps the curing process. If too much water is lost from the concrete through evaporation, the hardening process slows down or ceases. Concrete continues to gain strength after pouring for as long as it retains moisture, but the longer it moist-cures, the slower the rate of strength gain.
Is it OK if it rains after pouring concrete?
Pouring Concrete in Rain. Pouring concrete in the rain can compromise its strength, increasing the tendency for dusting and scaling to develop. Once the damage is done, it can be hard to rectify and will often ruin the appearance of the finished surface. Don’t let it rain on your parade.
