Can you put footings under concrete slab?

Yes, you may pour a concrete pad overlay over an existing slab. You need to consider the added height and weight of the overlay on the existing structure. Overlays may include polymers, portland cement concrete, or epoxies.

three daysQuikrete requires three days to cure underwater. If you simply put the bags around the post and allow the water to saturate the cement, leave the legs up for one week to ensure that the concrete sets.

Footing thickness - 8 to 12 inches. Footing depth - varies based on frost line and soil strength (some footings can be shallow, while other must be deep)

No, dont attach the slab to the house. Unless you put down a foundation, the slab will rise and fall with 'frost freeze'.. And, it 'will' crack your foundation.

Otherwise you could bury a pvc pipe in the concrete to run your gas line thru. Yes, you can bury the gas line. First I would bury a straight pipe larger than your gas line under the patio and then run the gas line in the pipe. If you ever need to replace the gas line it will be easy to remove.

The cost to replace a sewer line under a slab costs $3,000 to $5,000 for smaller jobs and $15,000 to $20,000 total for larger jobs.

Trenching under a slab can cost an extra $150 to $200 per foot..

However, if your concrete is relatively sound and raising its elevation a few inches would not create problems, then you can pour new concrete directly over the old. ... If you bond new concrete to old, any cracks in the existing slab will transfer up into the new slab, and usually within a day or two.

Once the subfloor of proper thickness is properly installed then you can apply cement board directly to the subfloor material. ALL CEMENT BOARDS MUST be installed in a fresh bed of thinset. ... If you want the cement board under the shower tray then do so - doesn't matter.

If the slab is too thin, it may break under load and fail before its time. If the slab is too thick, it costs more than it should. Slab thickness is a major factor in the cost of a concrete floor, so there's often pressure, which can become intense, to make the slab as thin as possible.

Water Cure Concrete made with Portland cement will harden even if it is completely under water.

In fact, one technique for curing a concrete slab is to build a soil dam around the perimeter of the slab, flood the slab with water and keep the slab covered with water for a week..

Yes, you may pour a concrete pad overlay over an existing slab. You need to consider the added height and weight of the overlay on the existing structure. Overlays may include polymers, portland cement concrete, or epoxies. You should improve the drainage of the slab by having a good slope on the overlay.

The ground beneath nearly all concrete slabs is damp-in fact, it nearly always has a relative humidity of 100%. That means it is a continuous source of water vapor into the slab and the slab will never dry out-especially if you put a coating on the surface that restricts the movement of water vapor.

For an outdoor tile patio installation to be successful, it needs a solid base, and a concrete slab is an excellent choice. ... If you already have a slab in place, that will save you some work. But before you can start tiling over this base, you need to examine it more closely.

With dry concrete and the right subfloors and vapor retarders, solid hardwood floors can be installed on slabs that are either on-grade (at ground level) or above-grade (above ground level). ... Wood floors should not be subjected to very wet conditions.

Signs Of A Leak Under Concrete1). There is water or damp spots on your floor. If hot-water lines are leaking, this may also lead to warm spots on your floor. ... 2). You can hear the sound of rushing water underneath your floor. ... 3). There is a significant increase in your water bill.Jan 10, 2021

Most exterior slabs do not need a vapor barrier. ... In general, place the concrete slab directly on top of the vapor barrier, with the subbase below. ... The vapor barrier can be placed under the subbase, if the building is closed in when the dry subbase material is placed.More items...

Slab construction is usually significantly cheaper than stumps. Designing and building your new property on stumps will involve the use of perimeter concrete strip footing, including possible internal strip footings and/or pads, with brick perimeter wall and internal piers in lieu of stumps.

A: It's perfectly acceptable to put tile directly on concrete — with a couple of caveats. First, it is important to determine if there is moisture coming up from the slab. You can test for moisture by taping all four sides of 18-by-18-inch polyurethane plastic on the slab.

Insulating under foundation and basement slabs using SPF (spray polyurethane foam) offers certain advantages over the more common method of using rigid foam board. ... Two-pound foam. Only closed-cell SPF can be used in a subslab installation; the open-cell foam does not have adequate compressive strength.

A concrete mix of 1 part cement : 2 parts sand : 4 parts coarse aggregate (by volume) should be used for footings. Concrete must be placed within half an hour of mixing. Brickwork – Place your concrete into your trench.

During the initial building of a home that has a concrete slab foundation and basement level, any plumbing that runs under the home must be put in before the concrete is poured, since the plumbing runs in the dirt, not within the actual concrete.

You don't need any cement board under the tub. It is far more important to have a sturdy layer of ply under the tub.

– Sand-Cement Grout A sand-cement grout can be used to fill voids under concrete slabs. This mix of sand, cement, and water is pumped through holes drilled to fill up the voids. While this method of slab jacking is cost-effective, there are major drawbacks to opting for this type of repair.

You can pour concrete over grass, and depending on the thickness of the slab you may not have a problem. However, because the location may be unevenly compacted you can be assured that cracks will occur. Generally footings and slabs should be laid on undisturbed soil where compaction is solid and regular.

Weakened water lines. Since water lines are laid down under the concrete slab, there can be minor damage such as small nicks when the concrete is poured. Although these occurrences may not cause immediate leaks, they can weaken the pipes and grow into a leak-causing crack later.

You don't need any cement board under the tub. It is far more important to have a sturdy layer of ply under the tub.

Use wire mesh for driveways that are 4 to 5 inches thick, and rebar for those that are 5 inches or more. Place rebar in a grid pattern with a spacing between bars of approximately 12 inches. In either case, blocks should be used under the reinforcement to keep centered within the concrete.

Registered User. permanent wood foundations require gravel, not concrete or soil for the footings - every situation is a little different, but all footings need to bear on the soil/gravel/bedrock/ whatever is supporting the structure equally, or it's going to settle at different rates.

six (6) inchesIt is essential that you keep your concrete slab at no more than six (6) inches of thickness. Also, it would be best to work the numbers out if you wish to work with any lesser as you can only put in one slab.

A slab-on-grade is a type of shallow foundation in which a concrete slab rests directly on the ground below it. A slab-on-grade foundation usually consists of a thin layer of concrete across the entire area of the foundation with thickened footings at the edges or below load bearing walls in the middle of the building.

Water Cure Concrete made with Portland cement will harden even if it is completely under water. In fact, one technique for curing a concrete slab is to build a soil dam around the perimeter of the slab, flood the slab with water and keep the slab covered with water for a week.

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.

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Footings with large bearing areas or unstable soil can benefit from adding rebar to prevent cracking..

Do I need a DPM under laminate flooring? Simply put yes. In order to prevent damp rising through the concrete floor and causing issues, a DPM should be used under all final floor types including wood flooring, laminate, vinyl and floor tiles.

InstructionsDig Under the Concrete. Dig out the soil, gravel, or other material from under the concrete, using a shovel and a pickax. ... Strike the Concrete. Lightly sprinkle the concrete with water to minimize dust. ... Pry Off Stubborn Pieces. ... Move the Concrete Chunks With a Hand Truck.Feb 19, 2020

Concrete made with Portland cement will harden even if it is completely under water. In fact, one technique for curing a concrete slab is to build a soil dam around the perimeter of the slab, flood the slab with water and keep the slab covered with water for a week.

edit - To put footings under the slab, you can cut holes wherever needed, excavate for footings (Sonotubes or concrete piers or similar) and then patch the concrete slab.

While you should never attempt to pour concrete footings in freezing temperatures, it is possible to pour footings in cold weather without cracking the concrete. Wait to pour the footings at a time when freezing temperatures are not expected for two weeks.

While you should never attempt to pour concrete footings in freezing temperatures, it is possible to pour footings in cold weather without cracking the concrete. Wait to pour the footings at a time when freezing temperatures are not expected for two weeks.

If you drive over a concrete slab that's got soft ground under it, the concrete wants to bend and stretch. ... If the concrete does develop a hairline crack, the crack should not open with the steel in place. Compacting the soil under the slab before the pour also prevents tension cracking.

Unfortunately, if you have clay-heavy soil, then you may run into difficulty when pouring a slab. The clay can compress under the weight of the concrete, causing the slab to shift or sink over time. ... With proper preparation, however, it's possible to pour a slab on clay soil without encountering these problems.

Concrete Footings are typically poured in temporary forms constructed from plywood or 2x lumber. Wood stakes and braces hold the forms in position. The top edges of the footing forms must be level, and the concrete footings must be set to the dimensions specified on the plans.

Concrete that carries heavy loads (such as footings, foundation walls and columns) almost always requires reinforcing steel. Not all concrete work requires reinforcing though. Concrete projects such as pathways, some driveways and small shed or playhouse floors, generally do not require any steel reinforcing at all.

In California they place sand between slabs and plastic vapor barriers—in Florida they don't. Almost everywhere (except “California”) that slabs are placed on the ground—a plastic sheet—a vapor barrier—is located directly under the concrete slab and on top of the ground (Photograph 1).

Registered User. permanent wood foundations require gravel, not concrete or soil for the footings - every situation is a little different, but all footings need to bear on the soil/gravel/bedrock/ whatever is supporting the structure equally, or it's going to settle at different rates.

In short, tile and grout are not inherently waterproof. ... Cement backer board is often used as a tile base on plywood or OSB subfloor. Cement backer board on concrete as a subfloor or underlayment is usually not recommended or needed. In most cases, you can apply tile directly to the concrete.

While not a requirement, a concrete slab foundation provides a solid, clean surface for your steel building and can help it last longer. Since the building will require anchoring to minimize shifting, pouring a concrete slab gives you a chance to pour footings as well.

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.

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..

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.

The sand layer cannot dry downwards by vapor diffusion because of the plastic sheet—it is a vapor barrier after all. In fact that's why we have it under the slab. We want a vapor barrier under the slab. ** We want to prevent water vapor from coming up from the ground into the concrete slab.