Guide to DIY Concrete Slab
In this DIY Concrete Slab page, we will discuss ways that you can save on your cement floors preparation. The procedures discussed will get you prepared for pouring concrete slab as well as concrete slab leveling. The procedures for preparing floor slabs on grade at or near ground level are described in concrete slab construction. Another approach to diy cement slab construction is monolithic concrete slab or monolithic slab show some quick way to build your slab.Diy concrete slab preparation for pour of cement floors requires a lot of hard labor. For homeowners looking to save on concrete work this is something that can be done with very little to no skills. If you are willing to do hard labor, you might be able to get the job done with a wheelbarrow and shovel depending on the size of the project and the type of soil.
In this discussion, we will be going over diy concrete slab procedures as you prepare to pour basement slab as per detail 5 below. In most cases, excavators will dig a hole where the bottom of the hole matches bottom of the footings.
The builder will then form and pour the footings followed by the foundation walls on top of footings. After the foundation walls are poured, the excavator comes back to backfill and compact the 10 inches before the slab is poured. The cost of leaving the jobsite and then comeback to do compaction and backfilling are included in his proposal.
As diy concrete slab, you can step in and do the work so you can save that cost. You must communicate with your excavator ahead of time that this is your intend. It is best to ask for cost breakdown when you first request bids. The cost breakdown you want are: 1. Cost to mobilize to and from your site, excavate, haul away extra dirt 2. Cost to mobilize to and from your site, backfill & compact for your cement floors.
Before going over the backfilling for the slab, let's discuss another cost saving opportunity with your basement footing labor. Down at the bottom of the hole that your excavator dug out, if the soil is such that you can easily with a shovel dig out the 10 inches deep & 20 inches wide footing that you need, go for it. I have done this several times.
In order to do this, you must layout the footings correctly, spray paint the layout on the ground and go to work. If you can dig out just enough for the footing, you will be able to pour the footings without forming. This will save you $5+/- for every foot of footing form work.
Two things to watch for if you don't form the footings:
1. The footing must be leveled
You can achieve levelness by pounding a steel stake at the middle of the footing spaced every 5 feet or so. Insert a nail in to one of the holes and tap the stake down until the nail marks the top of footing elevation. As you pour, make sure the top of footing matches the nail.
2. The dowls for the foundation wall must be centered at the wall.
The batter boards used to do your layout will make locating the center of the wall very easy. After you level your concrete at pour day, pull a string line and the center of your wall and stab the dowls.
If the inspector requires that the reinforcements be installed prior to the pour, pound a #4 bar about 4 ft long in the middle of footing spaced every 12 feet or so, tie a #4 bar horizontally, use two rows if needed. With the horizontal bar in place, hang your dowls from it.
It is extremely important to talk to your city building inspector about what you are planning to do. You need to make sure your method of construction is acceptable and you can find out if "stabbing the dowls" are acceptable. Every residential footing inspection I have scheduled, the inspector only checked the footing reinforcements, dowls installations were all stabbed after the footing is poured. On top of footing labor saving, you will also save on your diy concrete slab. Digging the footing down will eliminate the need to backfill and compaction before pouring concrete slab. The only thing left to do is install any plumbing and utility work that need to go underground, call for inspection if necessary and you are ready to pour your floor slab.
Ok, back to backfilling for the slab. During excavation, you need to make sure your excavator does not haul all the dirt away. You will need a compactor, shovel, wheelbarrow, and bobcat depending on the size of the project.
Your goal is to backfill 10 inches of the interior so that your slab can be poured on top of the footing as shown on detail 5. For a small project, say a 200 square feet basement addition, you can do it with a wheelbarrow, it is not easy but it can be done.
The biggest help will be a bobcat to dump the dirt into the hole but make sure to not put too much because you will have to dig them out again if you do.
For more information go to concrete slab construction
Why is the slab poured on top of footing?
This is a question often raised due to re-backfilling the areas that were dug out.
By pouring the slab on top of the footing, it will restrains the footing from sliding due to earth pressure from exterior. In addition to earth pressure, the footing must resist any lateral movement due to earthquake. At the top of the concrete foundation, floor joists and floor framing will brace the top of wall from leaning like a cantilevered wall. These two restraining points are the reasons footings for a house is only 20” wide versus 10+ feet wide footing for a cantilevered retaining wall of the same depth.
More on Concrete Slab Construction
Learn the steps for Concrete Slab Leveling
Back to diy concrete slab