Dennis O'Toole: Structural Repairs


Concrete Slab Foundations

The two main foundation types are Pier & Beam Founcations and Concrete Slab Foundations. Of the two, pier & beams foundations are generally less labor intensive to fix and are thus less costly. This is due to being able to access and work on the problem area through a crawl space.

What Is a Concrete Slab Foundation & How are they made?

1) Planning

The size and depth of the slab are determined. A concrete slab should have a minimum depth of 4 inches depending on use. For a garage, the depth should be 5-6 inches. The area should be carefully measured to final placement. The grade of the dirt also needs to be considered at this point considering the slab needs to be level. Additionally the dirt around the slab should be sloped away from the site at a rate of at least 1 inch per foot.

2) Excavation / Digging

The dirt needs to be removed to make space for the concrete slab. Assuming a 4 inch slab, the hole should be dug to 6-7 inches to allow for backfilling of sand or crush and run.

3) Make the concrete form

The concrete form is made of 2 x 4's and secured with stakes. The positioning of the concrete form needs to be perfect because this will be the final layout for the concrete slab. A laser transit is used by professionals to ensure the proper height of the concrete form.

4) Cleaning up / Backfilling

Any debris must be removed and the hole must be nice and flat. The soil should be compacted with a tamper. Sand or crush and run should be added to just below the bottom of the 2 x 4 concrete forms to allow for the proper thickness of concrete. The backfill will help with drainage and provide a good sub-foundation for the concrete. The backfill should be compacted again with a tamper.

5) Other Prepwork

Concrete wire, rebar and a moisture barrier can all be added at this point. The concrete wire and rebar will add extra strength to the structure and help reduce the chance of major settling. The moisture barrier will also protect the concrete from moisture below.

6) Pour concrete

The concrete is poured to the top of the concrete forms and screeded and leveled off. Bolts are placed in the concrete around the perimeter to later fasten the wallplates. The concrete is edged and worked to a smooth finish. A machine is typically used after the concrete has partially dried to work the concrete to a slick finish.

Understanding why you may have Foundation Problems with your Concrete Slab Foundation

There are several reasons why a concrete slab foundation could fail. It is important to both 1) Identify the CAUSE of your problem and also 2) FIX THE DAMAGE that has resulted. Common reasons for problems include:

1) Underlying Soil

Seasonal conditions cause the soil properties to change. When soil is full of water it naturally swells. When it dries out it contracts. The process over time undermines the integrity of the soil, and any foundation built on it. On the East Coast, namely Virginia Beach, and the Hampton Roads area, clay soils are the predominant soil type. Clay soils are the worst draining of all soil types causing a higher proportion of foundation issues.

2) Faulty Construction Methods

The soil should be prepped prior to the pouring of any concrete. For a highly clay soil like that of Virginia Beach, sand should be added to facilitate drainage. Foundation contractors should also tamp the soil with a tamper prior to ensure the soil is compact as possible to reduce the chance of any settling. The soil should be even before pouring any concrete. Additionally the use of rebar and fibers can be used to further strengthen the concrete footings.

The building codes in Virginia Beach, Norfolk, and Chesapeake were much more relaxed in the past than they are now. Many homes in the Hampton Roads area were built in the 1960's - 1980's. Contractors could get away with pouring concrete without doing the proper prepwork including proper backfill, rebar, and concrete wire. Some concrete foundations were poured too thin to save money on concrete.

3) Improper drainage

Water is your friend when you are drinking it or when you are taking a shower, but it is your enemy if it gets under your home. In some cases, busted plumbing under the soil compromises the soil and the foundation. Most commonly, the yard doesn't have proper drainage. The ground surrounding your home should be graded/sloped away from your home to allow the water to drain. If the water is pooling around and under your home, you have a problem you need to fix immediately before the damage is done.

Continue Reading: Concrete Slab Foundation Repair

Exterior Warning Signs

  • Brick or Block Cracks
  • Displaced mouldings
  • Pooling water around foundation
  • Separation around garage door, windows and/or walls
  • Stuck windows & doors
  • Interior Warning Signs

  • Baseboards & Casings detaching
  • Drywall Cracks
  • Nail Pops
  • Separating window & door jambs
  • Stuck windows & doors
  • Uneven Floors
  • We provide a professional report from a Structural Engineer with all of our repairs certifying the work has been performed to industry standards and meets building code restrictions. We have a Class A Contractor's License and are fully licensed and insured.

    All of our work is guaranteed to fix your foundation problem. We have a 5-year warranty on all work performed.

    Foundation Contractor in Virginia Beach specializing in house leveling, slab jacking, installation of additional crawlspace piers, slab repair and all other structural repairs in Virginia Beach, VA


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