why do i need crushed stone under concrete

Crushed Stone Calculator: Free Online Tool

See for yourself why a crushed stone calculator is so valuable, and how to use it properly. Why do I need a crushed stone calculator? While there are specific mathematical calculations that can be performed in order to determine the quantity of crushed stone to purchase for a project, this may not be the ideal route for you.

Read More
How important is gravel under a concrete sidewalk? (Home

How important is gravel under a concrete sidewalk? I got an estimate from a company on your list to replace my old, beatup concrete sidewalk. When they dug up the old sidewalk, there was no gravel underneath, and they wanted several hundred more dollars to dig out some of the dirt and put in a gravel bed is this necessary?

Read More
How to spread and level crushed stone.

How To spread and level stone. Here is a quick "How To" if you need to spread and level crushed stone I wish I had taken photos of the whole process, but I did not. Below find the secret if you do not have that Backhoe or Loader, or back blade on your Tractor, or, it is just a small job.

Read More
Few reasons why gravel is best to set and backfill a pool

Earl''s Pools of AL Why we feel that gravel is the best material to use when backfilling a swimming pool, Few reasons why gravel is best to set and backfill a pool with. Posted byJosh Bush on Tue, Feb 01, 2011 @ 16:02 PM 57 stone is used to backfill the side walls of the pool during installation. The size of this stone is about half an

Read More
The Recommended Gravel Base for a Concrete Driveway Home

The strength and durability of a concrete driveway are not only determined by the type of concrete mix but also by base or subbase over which it''s poured. A layer of gravel placed between the

Read More
Subgrades & Subbases for Concrete Slabs The Concrete Network

Now let''s look at why we need to know how flexible the subgrade is. To start with it''s important to understand that a slab on ground is designed as "plain" concrete. That means that we do not count on the reinforcing steel to carry any of the load. But wait, you

Read More
Crushed stone Wikipedia

Crushed stone is one of the most accessible natural resources, and is a major basic raw material used by construction, agriculture, and other industries. Despite the low value of its basic products, the crushed stone industry is a major contributor to and an indior of the economic wellbeing of a nation.

Read More
Does anybody use sand as a base before they pour concrete

Concrete cracks no matter what you do, that is why you see regular spaces groves or lines in sidewalks, its a control joint to allow cracking to occur there rather than where it wants. Otherwise, what is under a slab depends on the ground you are pouring the slab on, some soils don''t need anything, some need a

Read More
Crushed stone or slab under pavers around pool I''m going

Crushed stone or slab under pavers around pool I''m going to be putting pavers around the pool.. should go with a slab under them or is okay to just use crushed stone Thanks?

Read More
Concrete Floor Problems Building Science Corporation

May 26, 2008 · We can use crushed stone as a capillary break if there are no fines in the crushed stones—but the stones don''t act as a vapor barrier. So it is common to use crushed stones with no fines as a capillary break—and then add a plastic sheet over the top of the stones in contact with the concrete as a vapor barrier.

Read More
Gravel under concrete footing GreenBuildingAdvisor

Apr 01, 2015 · Crusherrun gravel compacts well but does not drain very fast at least not as fast as 3/4inch crushed stone (no fines). Talk to a soils engineer if you are worried but in my experience, either crusherrun gravel (compacted) or 3/4inch crushed stone can be used under footings. So can rigid foam. An engineer may disagree.

Read More
Sand under slab instead of gravel GreenBuildingTalk

Mar 04, 2013 · I''d want to know why the sand is so wet in the first place. If it''s just due to weather exposure and would drain/dry if under cover, that''s one thing. If it''s due to high water table, I might be inclined to build up the slab area with crushed stone (aka "gravel" in

Read More
How much gravel under concrete?

Nov 26, 2002 · Course if you''re in florida or texas that''s kind of moot!)and would use at least the same amount of gravel as the concrete. More important is good compaction of the base BEFORE you put the gravel down, then good compaction of the gravel itself. Better to do it

Read More
concrete pad or crushed stone under a shed Speedwake 2.0

Jan 01, 2007 · concrete pad or crushed stone under a shed Nice one''s are manufactured nearby so I''m going to get a 10 x 22 front entrance with aluminum siding to match the color of the house and shingle color. I was thinking concrete pad, but most of the shed providers recommend crush stone because it drains well and reduces moisture better than a concrete

Read More
Ask the Builder Concrete slab needs quality self

Feb 10, 2015 · What type of stone would be best for filling a cavity under a planned twocar garage addition? It is approximately 7 feet deep. The local concrete supplier sells recycled concrete for a

Read More
what do you use under concrete? Everything About Concrete

Q. We are pouring our garage floor on a new build, what kind of material do we use under it? The builder currently has some recycled concrete but we need to fill a little more space and level it out. We now have heard that the recycled concrete is not the way to go, but to use pea sized wash stone, that it compacts and levels better.

Read More
How Much Base Material Do I Need for Walkways, Patios and

How Much Base Material Do I Need? Deciding the correct amount of walkway base material is actually quite simple. For sidewalks and patios or any other light duty areas you will only need a 4 inch base of 3/4 inch quarry process or RCA beneath a 1 inch layer of concrete sand.

Read More
gravel under concrete slab? is it absolutely required

gravel under concrete slab? is it absolutely required? Ask Question Asked 2 years, 5 At the end of the day, it is just much, much easier to pour 5.5" thick of concrete, but I do think 1.52" of gravel under it is a good idea, just a much more difficult bit of logistics. user contributions licensed under cc bysa 4.0 with attribution

Read More
Do you need to put gravel under a concrete pad? Yahoo

May 12, 2008 · well, you need to remove any and all black dirt first. Reason for this is because black dirt can compress, and as it does this the concrete will have a void under it, and eventually crackeither from water that gets under and freezes, or just because there''s nothing under it to support it.

Read More
Should vapor barrier in slab be under 4 in. of gravel or

May 03, 2011 ·łpart question: 1) I''m building a 2car garage with upstairs apartment in zone 4, 26'' x 28''. getting different opinions on whether the vapor barrier 6ml plastic should be under the 4'''' of gravel or on top of the gravel directly under slab? Some are saying it is not good to pour concrete right on plastic, although this seems to be the most common way to do it.

Read More
Information on the Do''s and Don''ts concerning Foundation

Information on the Do''s and Don''ts concerning Foundation Drainage. Concrete or Masonry Foundations (NEC R405.1) Drains shall be provided around all concrete or masonry foundations that retain earth and enclose habitable or usable spaces loed below grade.

Read More
Shed Foundations Made Easy The Best Types Explained

Sep 17, 2012 · There is already a crushed stone floor. Can I dig a trench, fill it with stone and lay 4ࡪ''s or 2ࡪ''s on top of it for a foundation? If so, would they have to be pressure treated? Do I even need crushed stone if use pressure treated wood on top of dirt Would concrete blocks or pavers with 2࡬ headers be a better idea?

Read More
Understanding Basements Building Science Corporation

Oct 26, 2006 · The concrete slab should be sealed to the perimeter basement wall with sealant (the concrete slab becomes the "air barrier" that controls the flow of soil gas into the basement). The crushed stone drainage layer under the basement concrete slab should be vented to the atmosphere to control soil gas . Atmospheric air pressure changes are on

Read More
Concrete Slab How to install a slab from start to finish

It doesn''t have a foundation or any concrete walls under it or around it. In Maine we install a lot of slabsongrade for houses and garages. THE TOOLS YOU NEED TO BUILD A CONCRETE SLAB. Click on CONCRETE MIXING RATIOS to learn what the correct proportions of cement, sand, stone, and water are to mix your own concrete by hand.

Read More
Why Should You Put Gravel Under a Deck? Hunker

A lot of planning goes into constructing a deck beyond choosing your deck size and supplies. Even if you choose to build your deck with highquality, weatherresistant materials, the elements can impact and diminish the deck''s quality over time if care is not also applied when preparing the deck site.

Read More
Why Put gravel under concrete? (2019 UPDATE)

May 06, 2010 · I have poured many small sidewalks and shed floors and never put gravel under the concrete. I want to pour a driveway section in front of the garage and was told by a guy at the concrete company (who came to measure the amount needed), that I need to put gravel under the concrete.

Read More
Crushed Stone Under a Spread Footing Geotechnical

Dec 17, 2009 · Hey all, we all have seen recommendations like remove a foot or two underneath the proposed footing level and replace it with crushed stone bridge lift. Can someone explain me as to why we do that when we run the settlement analysis with the original soil profile.

Read More
9 Best Uses for Crushed Stone DoItYourself

Crushed stone is exactly what it sounds like, rocks that have been crushed or broken down by crushing machines. Its main uses are as an aggregate for construction and landscaping purposes. Crushed stone and gravel are different in that natural processes produce gravel and its surface is rounded as opposed to the more angular surfaces of crushed stone.

Read More
Shouldn''t I Have Gravel Under Concrete Footers? Concrete

Sep 29, 2012 · Our contractor is telling me that a layer of gravel is not needed under the concrete footers. I called the inspections office in my area and spoke to the lead inspector in my area and he told me the same thing, but couldn''t tell me why gravel isn''t needed under the poured concrete. I called the inspector for a second opinion.

Read More
compact fill under slab Do It Right Not Over

Compact Fill Under Slab Concrete bends and breaks. Use selfcompacting fill. Water helps compact. Concrete block ledges on footer. The steel bars need to be placed so they line up with the concrete block pilasters. If you have to use crushed stone, be aware that it requires mechanical compaction so the pieces of gravel interlock.

Read More
Graniterock: Technical Reports

Vapor Barriers under Concrete Floor Slabs: Friend or Foe? by Steve Ragan, Director, Research and Technical Services The answer to this controversial question, from both angles, is a qualified "yes." Vapor barriers have been associated with certain concrete slabon

Read More
How Much Crushed Stone Do You Need? A SureFire Formula

Crushed stone is a material that is typically used as a base or underlayment, upon which the stuff that actually shows for example, the concrete of a patio will rest. Guessing is rarely a good solution to such dilemmas when undertaking a big project, so let''s look at a (relatively) simple way to figure out the correct amount.

Read More
Determining What Size Crushed Stone You Need For Your Project

Crushed stone is used for a wide variety of projects, from building roads to providing suitable drainage and from laying a base for pavers to enhancing the look of landscaping projects. There are so many uses for this versatile material, yet many people are unsure of what size they need when it comes to selecting the proper material for their project.

Read More
What Type of Base Do You Need For a Hot Tub? Spa

I definitely wouldn''t do flagstone under a hot tub. You are right, too hard to get perfectly level and smooth so the whole base is supported evenly. I would just keep the pad, do a decorative crushed stone around the perimeter of the spa to cover up the edges of the concrete pad, then do

Read More
Patio Design: Understanding Crushed Stone DoItYourself

Patio design with crushed stone is easy, practical and more affordable than pavers or poured concrete. It stays confined between borders, and resists sinking below ground. Its shape creates a mosaic effect on your patio surface. Crushed stone is any stone material, including granite, shale or slate

Read More
Does anybody use sand as a base before they pour concrete

Concrete cracks no matter what you do, that is why you see regular spaces groves or lines in sidewalks, its a control joint to allow cracking to occur there rather than where it wants. Otherwise, what is under a slab depends on the ground you are pouring the slab on, some soils don''t need anything, some need a lot of help.

Read More
Proper Subgrade Prep Concrete Construction Magazine

Sep 20, 2007 · These imported fills may include granular materials such as sand, gravel, or crushed stone. These highstrength and permeable materials offer low compressibility, which is ideal for a slabsupport system. Contractors often ask how to backfill foundation walls for an area that will end up under concrete flatwork.

Read More
compacting gravel under a slab JLCOnline Forums

Dec 07, 2004 · Re: compacting gravel under a slab Tucker: With 2 to 3 feet of rock, I fail to see why you need either poly or insulation under the slab, I think I would opt for the "oozing" and the thickening effect of the "waffle" bottom, I would think that structurally it turns a 3 1/2" slab into something more like a 6 or 8" slab from a structural standpoint.

Read More
Crushed Stone Under Concrete: Why It''s Needed

When working with concrete slabs, it''s important to take the appropriate steps to ensure that it lasts for many years to come. In order to get the most use out of your concrete slabs, you need to add a layer of crushed stone beneath it first.Placing crushed stone under concrete serves several purposes and can provide the following benefits.

Read More
Gravel or Sand Below a Foundation Foundation engineering

Jun 05, 2007 · If you are wanting to provide a working platform to prevent disturbance due to steel placing, leveling course, to minimize precipitation disturbance, I would use a layer of crushed stone or a blinding mat (mudmat) or a well graded sand and gravel (like a subbase or base course).

Read More