- 1 How deep does a concrete foundation need to be?
- 2 Can you pour concrete directly on dirt?
- 3 How deep do you pour footings?
- 4 Do you need gravel under concrete?
- 5 What type of concrete is used for foundations?
- 6 Should I put plastic under concrete?
- 7 Do you need rebar for 4 inch slab?
- 8 Is Clay a good base for concrete?
- 9 Why deck posts should not be set in concrete?
- 10 Can you use concrete blocks for footings?
- 11 Do footings need rebar?
- 12 What are the 3 types of foundations?
- 13 What is the standard footing size?
- 14 How do you calculate footing size?
How deep does a concrete foundation need to be?
Wall Footing Thickness.
For masonry or concrete construction, the minimum foundation wall will be 6 inches. The minimum reinforced concrete footing thickness will be 6 inches or 1-1/2 times the length of the footing projection from the foundation wall, whichever is greater.
Can you pour concrete directly on dirt?
Long story short, yes you can pour concrete over dirt.
How deep do you pour footings?
In areas with freezing winters, a concrete footing usually must extend at least 12 inches below the frost line (the depth at which soil freezes). A footing should also be at minimum 8 inches thick and twice as wide as the wall or posts it will support.
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 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.
What type of concrete is used for foundations?
High-Strength Concrete Mix: When durability is key, high-strength concrete makes a great choice. This is ideal for foundations, footers and heavy equipment bases.
Should I 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.
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.
Is Clay a good base for concrete?
The clay can compress under the weight of the concrete, causing the slab to shift or sink over time. It also can leach moisture from the concrete itself, resulting in uneven curing and a brittle base. With proper preparation, however, it’s possible to pour a slab on clay soil without encountering these problems.
Why deck posts should not be set in concrete?
A deck post should always be placed on top of footing, not inside concrete because it can break. Concrete tends to absorb moisture and wood expands when it gets wet, so these two factors combined will result in the wood breaking the concrete.
Can you use concrete blocks for footings?
Ensure a solid footing. Footings should be a minimum of twice the width of the concrete block (i.e., a typical 8x8x16 block would require a 16-inch wide footing) and extend below the frost line. NOTE: it is important to check local building codes for construction requirements in your area.
Do footings need rebar?
Using Rebar for Concrete Deck Footings
Plain concrete deck foundations without rebar are acceptable under the minimum standards of construction established in the International Residential Code. Footings with large bearing areas or unstable soil can benefit from adding rebar to prevent cracking.
What are the 3 types of foundations?
But chances are your house has (or will have) one of these three foundations: full basement, crawlspace, or slab-on-grade. Other variations are possible. Here are the three main types of house foundations that you will encounter in residential construction.
What is the standard footing size?
Under every house is a foundation, and under most foundations are footings. Most of the time we take footings for granted, and usually we can: For typical soils, a common 16- or 20-inch-wide footing can more than handle the relatively light weight of an ordinary house.
How do you calculate footing size?
How to Calculate Footing Size
- Determine the width and length of the cement slab in inches.
- Divide the width by 12 to convert it to feet.
- Divide the length by 12 to convert it to feet.
- Determine the depth or thickness that is required for the footing in inches.
- Multiply the width by the length and then by the depth.