What kind of gravel do you put under concrete? Most concrete contractors want a mix of coarse and fine aggregate to create a compactable base that is going to be safe for settlement and drainage. Crusher run (a mix of crushed stone and stone dust) is one of the best base materials for concrete flatwork. What is the compaction rate of gravel?

Jul 04, 2014 What goes under the concrete in a slab-on-grade home? In the old days, not much — just dirt. Eventually, contractors discovered that it made sense to include a 4-inch-thick layer of crushed stone under the concrete. The crushed stone provides a capillary break that reduces the amount of moisture flowing upward from the damp soil to the permeable concrete. Since the crushed stone

May 02, 2017 According to BSI-003: Concrete Floor Problems, Joseph Lstiburek, May 26, 2008: (click through to freely read full article - entertaining as well as informative!) The plastic sheet also acts as a capillary break. 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

the stone. The crushed stone is not easily displaced during concrete placement, can support construction equipment for compaction, and elim-inates any pumping at the joints. Ad-d i t i o n a l l y, a thin layer of sand is usu-ally used on top of the crushed base to minimize subgrade drag between the crushed stone and the concrete s l a b

Dec 17, 2009 Yes. If you have a fluctuating water table that impinges the bottom of the footing, the fine sand and fines below the gravel can work their way into the gravel voids; however, that should not be significant. RE: Crushed Stone Under a Spread Footing. DRC1 (Civil/Environmental) 23 Aug 09 23:20

Apr 27, 2021 Depending on what the driveway will be used for, the base may need to be 4 to 12 inches. Ideally, 6 inches of crushed stone or gravel should be used

DEAR TOM: Un-compacted fill under concrete slabs of any type is a recipe for disaster. The slab could be for an entire home, it might be an exterior patio slab, a front porch slab, a driveway, etc. Concrete is an amazing material, but it has an Achilles heel. ... If you have to use crushed stone, be aware that it requires mechanical compaction

Apr 16, 2011 I am getting ready to have a foundation poured for a garage this summer, I am new to foundations so I asked my building inspector what kind of stone I needed under the slab and the only response he would give me was You figure it out It would have taken him less effort to list the stone, but thats for another day. Anyways, help is appreciated, I have come across a dozen different

Adding crushed stone under your concrete slab will provide a level surface for your foundation. Simply pouring concrete onto the ground will expose it to elemental erosion that will cause cracking and sinking. Similarly, if there are roots or plants under your slab, they may rot and cause unevenness

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

Nov 07, 2019 Recycling crushed concrete to be reused helps reduce landfill crowding AND saves more resources from being used to create new concrete. Old concrete can be crushed down to specific sizes, cleaned so that unwanted debris is removed from the mixture, and reused as a solution to a number of construction and landscaping problems

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Gravel, or crushed stone, provides a stable surface for your concrete slab. Even the most solid, compacted soil can shift dramatically with the weather changes, which will undermine your slab and cause cracks. It is important to note that not all gravel is the same

Apr 28, 2014 A Level Surface. Adding crushed stone under your concrete slab will provide a level surface for your foundation. Simply pouring concrete onto the ground will expose it to elemental erosion that will cause cracking and sinking. Similarly, if there are roots or plants under your slab, they may rot and cause unevenness

Jul 27, 2020 This material is a great choice for railroad projects and those that require drainage. #5 – Crushed stone #5 is 1 inch or smaller in size. This material is perfect for road and paver base. #8 – These stones are between 3/8 and 1/2 inch long. It is the most common stone used for concrete mixes

Nov 11, 2019 Parts of crushed stone are commonly used as aggregates for ready mix concrete. Concrete plants keep large quantities of different parts of crushed stone on hand to make their concrete batches. Crushed stone with stone dust in it is highly compactable and is therefore commonly used when making any kind of base for construction

Jun 22, 2020 The usual range employed is between 9.5mm and 37.5mm in diameter. - Fine aggregates are usually sand or crushed stone that are less than 9.55mm in diameter. Typically the most common size of aggregate used in construction is 20mm. A larger size, 40mm, is more common in mass concrete. See full answer to your question here

Sep 16, 2020 The problem is the crush and run - or crusher run as I've heard it called - is compact-able - and 57 stone - gravel - naturally is compacted when it's dumped/spread. so you have the chance of settlement under/of the concrete and or cracking of a slab with a compact-able sub-base - unless you are able to fully compact it in lifts - layer by layer

Jun 30, 2010 The crushed stone on the other hand does not. So if you use crushed concrete below your slab, its going to take up that water from the damp soil below, and its going to carry it right up to the underside of your slab - defeating the entire purpose of the stone layer. So, a word of advice. Don't do it