Should i put gravel under concrete

As a general rule, any section of concrete must have at least 0. Can you use pea gravel under concrete? While pea gravel can be used as a mulch alternative, garden border and other landscaping purposes, it is not the best choice for a patio base.

How do you prepare the ground before pouring concrete? Preparation is the most important aspect of pouring a concrete slab. Dig the ground down to the proper depth. Smooth out the ground with the flat side of a rake so that you have a level surface. Tamp the ground with a hand tamper or mechanical tamper.

Pour 2 inches of small, rounded gravel for additional drainage needs. What can I use to fill under concrete? 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. What do you put under a concrete slab? Zhenhua Gervasi Pundit. Do you put gravel under footings? If the soil is very strong, this may not lead to problems. In soils with bearing capacity greater than about 4, psf, I suggest excavating next to the footing and under it, and placing compacted large gravel into the space.

That should be adequate to support the wall. Karlota Miheenkov Teacher. How thick should a concrete pad be? Arsenia Altisent Supporter. Do I need rebar in concrete patio?

Rebar Basics. Malick Cintado Supporter. How long should you keep fresh concrete covered with plastic? Ileana Markhinin Supporter. Do you need crushed rock under concrete? Crushed stone under concrete provides a level surface for you to lay your foundation on.

If you pour concrete directly over the ground, it could erode away over time, and this would cause your slab to sink. The solid foundation that the crushed stone provides will offer the support the concrete needs. Jennefer Olaverri Beginner. Can I pour my own driveway? Ignacia Dicker Beginner. How much gravel do you put under concrete? A minimum thickness is inches of well compacted gravel should be your target.

If you use a plate compactor, run it over the gravel to pack the material tight. Push the plate compactor slowly from side to side, running in an east-to-west direction. Switch directions, running the plate compactor north to south and working from the opposite end. If you use a hand tamper, simply thrust its square, metal plate against the gravel to pack it tight. Spread another 2-inch layer of gravel over the first 2-inch layer of gravel.

Spray it with a mist of water. Pack the second layer of gravel tightly by using the plate compactor or hand tamper. Check the gravel layer for levelness when finished. 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.

I should mention that I always put lots of small to medium sized rocks under concrete to save on the amount of concrete needed. I save all rocks I get just for that use, and leave them get rained on to clean them. Any rock that will not exceed the height of the forms, goes in there. Because this will be driven on, I intend to put in some rebar, which I never do on sidewalks and shed floors. I have never had any problems with these sidewalks cracking or substantially lifting in winter.

Notify me about replies to my post Post Reply. Hustlin' Hank Contact options for registered users. Show Quoted Text. Reply to Hustlin' Hank. DanG Contact options for registered users. I wish you had asked him for a better clarification.

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. The concrete is prone to cracking wherever the slab gets thinner no matter how thick it is. This is usually accomplished by using a select subgrade fill which varies around the country depending on what is available and inexpensive.