Do you need sand under concrete slab?

The calculator will indicate the number of 60 or 80 pound bags of QUIKRETE® Concrete Mix you need to build a 4″ or a 6″ slab.

You will need 1000 lbs of sand for the mortar for those 100 blocks. The Recipe for Mortar sand mix will be 1 Part Mortar to 2-1/2 Parts Sand.

For every m2 of wall you will need ten concrete blocks. For every ten blocks you will need two 25kg bags of bricklaying mortar. If you are working on a larger project it may be more economical to mix your own mortar. For bricklaying you need to mix one part of cement to five parts building sand.

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.

A 60-pound bag yields . 017 cubic yards, and an 80-pound bag yields . 022 cubic yards. For a 10 x 10 slab, you would need 77 60-pound bags or 60 80-pound bags.

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..

For every m2 of wall you will need ten concrete blocks. For every ten blocks you will need two 25kg bags of bricklaying mortar. If you are working on a larger project it may be more economical to mix your own mortar. For bricklaying you need to mix one part of cement to five parts building sand.

You do not need rebar for any slab if you make it thick enough and space the joints properly. Rebar in jointed pavement is there to counter the cupping effect of thermal expansion. I always recommend the use of rebar or at least rewire. Any concrete slab can crack.

All 3 types of slabs will need a footer and a slab of at least 4″ thick. The footers depth needs to be the depth of the frost line or as per local code, but no less than 12″ deep. ... Slab Foundations Like all foundations, the slab starts with concrete footers poured 24 inches below projected finish grade.

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..

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...

Concrete is strong in compression, but not under tension. So, if it flexes, like a slab with a vehicle on top of will do, it cracks at the bottom whre the flexing becomes tension. ... Mesh will help mitigate the chances of cracking of the slab due to differential settlement.

You do not need to sand the concrete before staining unless you are using Acid Stains and the surface to be acid stained is not capable of absorbing liquids..

Not only is thinset a critical component underneath cement board but the other critical component is the fasteners.

And you won't have the fasteners if you are trying to install it over concrete..

Select a pipe of sufficient diameter for the desired excavation width. ... Dig a small trench on each side of the concrete slab. ... Measure the width of the concrete slab. ... Push the angled end of the PVC pipe into the soil in the trench on one side. ... Tap the other end of the PVC pipe with your sledge hammer.More items...

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.

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.

Creating an insulation layer and a vapor barrier between the concrete slab and the ground beneath it is the best practice in insulating basement floors.

The insulation barrier will help keep warm air in, and the vapor barrier will keep unwanted moisture out..

A 50mm thick layer of proprietary floor slab insulation is usually enough to reach and maintain the target U value but this should be checked with an architect first. Insulation sheets should be laid tightly together with the joints staggered to avoid movement.

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.

To create the base, spread a 4-inch layer of gravel over the excavated area. Level the gravel, following the initial grade, and cover it with a 1-inch layer of sand. Tamp the gravel and sand down with a plate compacter before laying the blocks.

Pour concrete over a solid, well-drained base Because concrete slabs “float” on the soil, soft ground or voids underneath may cause unsupported areas to crack under heavy weight like vehicles. Pack about 4 in. of sand or gravel over clay and other poorly draining soils to provide even support.

Sharp Sand (which has larger grains) is used for concreting or laying paving slabs and Soft Sand is used for bricklaying, etc.

It is also possible to buy mixed aggregate containing both coarse and fine aggregates..

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.

To plaster 100 square metres (15 millimeters thick) you will need: 14 bags cement + 2,25 cubic metres sand. Using masonry cement complying with SANS 50413 class MC 12,5X. To plaster 100 square metres (15 millimeters thick) you will need: 20 bags cement + 2 cubic metres sand.

Your project is 32 square feet at a depth of 4”. Here is the quantity that you will need for your slab. Quikrete Concrete Mix: 24- 60lb bags.

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

And yes, mesh is important: Concrete is strong in compression, but not under tension. So, if it flexes, like a slab with a vehicle on top of will do, it cracks at the bottom whre the flexing becomes tension. Steel mesh will prevent this to a large degree and hold it all together.

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.

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.

You really do not want the patio level with the house threshold, too easy for water to get in to the house. As for the slab, it will not settle if you prepare the subgrade correctly. You need the footers to support the structure, the slab is just there to walk on, and has no structural importance.

The application of vapor barrier in exterior concrete is unnecessary due to the fact that water penetration does not matter. Any slab on grade that is enclosed and on the interior of a building should have a vapor barrier installed prior to pouring concrete, especially if flooring will be applied.

Installing pavers is very similar to concrete installation. You must start with a solid base and foundation. Most frequently, this involves digging down into the ground and removing the existing dirt and replacing it with gravel and sand.

Yes! A strong gravel base is required when building a concrete patio in order to prevent the concrete from shifting or cracking. Adding gravel under the concrete also provides a level surface for your foundation and adds proper drainage when there is pooling water.

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.

Wire mesh, like Rebar reduced the cracking and any uplift in the concrete driveway. Rebar will be used if there is a structural reason, meaning you need to carry the weight of the slab to pilings or plan to build above the slab. For a driveway, just use the wire, lap it one box around.

InstructionsCover the concrete slab with 4 mil plastic sheeting if you're working near windows.Dig under the concrete if you're able to do so.Start to break the concrete, starting six inches from the edge and working your way in. ... Pry with a long bar or wrecking bar as you go. ... Cut any mesh wire with bolt cutters.More items...•Oct 14, 2019

For a 10 x 10 slab, you would need 77 60-pound bags or 60 80-pound bags. If we add an extra 10%, that's an extra 8 60-pound bags or 6 80-pound bags.

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

Really depends on what the slab is used for but in general no you can install wire mesh or use fibered concrete. However you do need something to tie the concrete it just doesn't have to be rebar. You do not need rebar for any slab if you make it thick enough and space the joints properly. ... Any concrete slab can crack.

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.

Enter the size of the slab you want to build in square feet. The calculator will indicate the number of 60 or 80 pound bags of QUIKRETE® Concrete Mix you need to build a 4″ or a 6″ slab. (All yields are approximate and do not include allowance for uneven subgrade, waste, etc.)

2 Answers from MyBuilder Landscape Gardeners You need approximately 0.75 cubic metres of gear. A ton bag of sharp sand is around 0.5 cubic metres so 2 bags will be plenty and 10 cement.

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..

Not only is thinset a critical component underneath cement board but the other critical component is the fasteners. And you won't have the fasteners if you are trying to install it over 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.