gravel size under concrete slab

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How much gravel under concrete? - Page 3

Commercial requires an 8" slab on 6" of gravel. The others have already indicated the type of gravel. If I were doing a drive, I would think 6" on 4" of gravel to be the minimum. A couple extra inches doesn't cost much compared to having it crack up. Of …

What size gravel to use under concrete pad | DIY Home ...

Joined Jan 3, 2011. ·. 5 Posts. Discussion Starter · #6 · May 9, 2011. Yes to your questions on rebar and placement of it. Since posting I've chatted with an engineer friend who said 4" concrete is plenty. He also suggested 1" sand, then 4" of 3/4" gravel (compacted) then the 4" concrete. Am going to try that!

What size crushed stone for concrete slab?

Coarse gravel, like 57 stone, under a slab is used as a capillary break to prevent ground moisture wicking up through the concrete. All good concrete needs the bottom almost as flat as the top, creating a uniform thickness to maximize strength.

gravel under concrete slab? is it absolutely required ...

Its about 3.75 cu yards of crete, or like $400 It will cost $100 for gravel to fill in 2", but my crete is still only a little cheaper, and it will be a thinner slab. I could put gravel in, say 2" and 3.5" of concrete over that or just full 5.5" of crete or I could do lot of gravel and a 2" top coat over that with a bunch of steel and fibers,

Gravel under Concrete Slab | Pilots of America

For the Civil Engineers out there. Does anyone know of any real reason to spend the money to put gravel under a concrete slab? I have always just graded the dirt under the slab so it drains off to the sides or bottom same as the concrete slab will drain, compacted it and called it good.

Gravel under garage floor? - GreenBuildingAdvisor

The sub-grade preparation (gravel layer) is a structural element very important for the longevity of the concrete slab, entirely apparent from its role in water control. In my area, no one would use sand. 4 to 6 inches, compacted densely (90% or to refusal), of 3/4-minus crushed rock (gravel) would be typical.

The Recommended Gravel Base for a Concrete Driveway | Home ...

Concrete Network explains that the two levels underneath driveways include the subgrade of native soil topped with a subbase of gravel underneath the …

Should You Put Rigid Insulation Under Concrete Slab?

Depending on where you live, rigid insulation under a concrete slab might be required! The IECC, a regulatory code that ensures new construction is environmentally conscious, requires a minimum of R-10 insulation in Climate Zones 4-8. You can check if you live in one of these zones on the IECC zone map.. If the IECC requires rigid insulation under concrete slab, you'll also need to get an ...

compact fill under slab - Ask the Builder

Soil Settles. If un-compacted, or poorly compacted, soil or fill sinks under a slab you end up with a hollow spot. If you drive on this concrete and apply pressure to it, the concrete tries to bend or stretch to conform to the hollow spot. The result is almost always a crack and the concrete slab drops down.

How much gravel do I need for a concrete slab?

A hand tamper is sufficient for packing gravel, but a plate compactor makes the job much easier, especially when preparing a large area such as a patio. Excavate the soil to a depth of 8 inches, allowing 4 inches for the gravel base and 4 inches for the concrete slab.

What Stone goes under concrete slab?

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.Gravel allows water to drain into the ground below. When packed tightly, however, the …

Do you need gravel under a concrete slab? - Quora

Answer (1 of 7): I agree with David Powers and disagree with a statement made by Michael Dillon. Short answer is "yes" but rather than gravel one should use a material that will suffer compaction such as ABC (aggregate base course), crushed concrete, or even (depending on soil conditions), bank s...

What Type Of Gravel Under Concrete Slab - Walesfootprint ...

3 Reasons To Use Crushed Stone Under Concrete Slabs B R Sand. Proper Subgrade Prep Concrete Construction Magazine. Aggregates The Difference Between Crushed Stone And Gravel. View Of A The Concrete Slab Over Vault Edge Beams And B. Gravel Vs Concrete Shed Base Which Is A Better Choice. Subgrades Subbases For Concrete Slabs The Network.

How Much Gravel Do I Need for a Shed Foundation? - Site ...

To determine the amount of gravel you will need for your shed foundation first calculate the square footage. In the example diagram shown, a 12×14 shed foundation, the square footage is 168. Next, multiply the square footage by the depth of gravel. If we use 6" of gravel, or 0.5 feet, our cubic footage is calculated as 168 x 0.5 = 84 cubic feet.

How much gravel under concrete? - TractorByNet

Not just ordinary gravel. What is needed is processed gravel of the type that your county will put on its gravel roads. This gravel has a wide gradation of material size including some clay fines. Under proper compaction techniques, ie. plate compactor and correct amount of water, a well compacted gravel base will feel like concrete itself.

What is the best base for concrete slab? - True DIY

For a 120-square foot patio that works out to 40-cubic feet of gravel. Also, What Stone goes under concrete slab? crushed stone. Can you put footings under concrete slab? 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.

Ask the Builder | Concrete slab needs quality self ...

Because it's going to have cars and perhaps a pickup truck on it, I'd make sure the concrete slab had No. 4 steel bars, commonly called half-inch rebar, installed at 2-foot centers in both ...

Sand Gravel and Stone Calculator - Concrete Enterprises LLC

inches. Material: Concrete sand Masonry Sand #8 Gravel #67 Gravel 2 Inch Gravel #57 Bluestone #67 Bluestone #7 Bluestone #8 Bluestone CR6 Bluestone 3/4in. Lightweight. Per cubic foot: Tips for Ordering Concrete. Quality – Concrete is a perishable product and should be treated as such. Time, weather conditions including a temperature of the ...

7 Different Crushed Stone Sizes and Their Applications

#57 – This category refers to a stone that is about 3/4 inch long. Most typically use it for concrete mix, landscaping, and drainage. #67 – Crushed stone #67 includes stone that is 3/4 inch or smaller in size. #67 is a great material for road and slab base as well as fill.

What size gravel is best for concrete? - Quora

Answer (1 of 2): 20mm (3/4 inch) is standard for structural purposes, unless certain other factors are at play, such as reduced cover to reinforcing bars, in which case 10mm (3/8 inch) gravel may sometimes be used. The size of the gravel will affect the strength of the mix, so, for structural pu...

Pea gravel for interior floor slab support - Geotechnical ...

2. Geodude1 (Geotechnical) 1 Feb 06 14:56. Pea gravel is still commonly used under floor slabs and tight places. Floor contractors don't like working with it because it displaces so easily under foot and while placing concrete. Many contractors in the Puget Sound region have opted for clean, crushed rock such as 5/8".

Fill under slab? - Fine Homebuilding

The bottom half of concrete layer be dryer than the top which will cure at a different time causing cracking. Beside the sand and aggregate needs to control the ground water under the slab. A VB will block this under the aggregate. As far as insulation.

What Size Gravel Under Concrete Slab - Walesfootprint.org ...

What Size Gravel Under Concrete Slab. Quality concrete slab design subgrades subbases for concrete slabs crushed stone compact fill under slab ultimate cheat sheet for concrete slabs what base material under concrete slab. Gravel vs concrete shed base which is a better choice the ultimate cheat sheet for concrete slabs sakrete build a concrete ...

Do you need gravel under concrete?

You will need 3 inches of gravel under a concrete slab that is 4 inches thick. More gravel is better, but 3 inches is the minimum amount of gravel you should have with a 4" slab. Use ¾" washed and screened gravel, then compact it to level.

Do You Need Gravel Under Concrete Patio, Slab, Footings?

Yes, you should put a vapor barrier under concrete slabs to prevent moisture from wicking up into the slab and onto the surface of your concrete slab, patio, or driveway.Ensure the vapor barrier is above both the gravel and rigid foam and immediately below the slab. Moisture wicking up into a slab can cause unsightly wet spots on top of your slab, and the efflorescence can be hard to remove.

What Type Of Gravel Under Concrete Slab | FarmChat

What type and size of gravel do you suggest using under a concrete slab? There's supposed to be four inches of subbase and two inches of base, but the sizes for both have me a little lost and I'm getting conflicting advice.

Subgrades and Subbases for Slabs| Concrete Construction ...

The subbase, according to ACI 302.1, "Guide to Concrete Floor and Slab Construction," is a layer on top of the subgrade of "compactible, easy to trim, granular fill that will remain stable and support construction traffic.". In some cases, a base layer is placed on top of the subbase. All of these layers together comprise the soil ...

What kind of stone under concrete slab? | DIY Home ...

I asked him a specific question with him knowing the specific type and size of foundation, location and drainage attributes. He chose not to answer it. it's going to be a pier slab system, 6" thick slab poured together with 12" dia. footings about every 6 feet.

Gravel Calculator | How much gravel do you need?

Size – there are many sizes of gravel. We can find some with rock fragments 4 inches (about 10 cm) in diameter and others with a particle the size of your fingernail. Of course, different sizes serve different purposes. Normally, we would like our gravel path to consist of 2 …

How much gravel do you put under a concrete pad?

When packed tightly, however, the gravel doesn't shift beneath the concrete. What do you put under a concrete slab? Just scrape off the sod and topsoil and add gravel fill if needed. If you have clay or loam soil, you should remove enough to allow a 6- to 8-in. layer of compacted gravel under the new concrete. If you have to remove more than a ...