Underpinning

The process of removing the soil underneath a concrete slab or crawl space to create a lower support level, followed by the addition of new walls, floors and concrete footers, to extend the depth or strengthen an unstable foundation.

When done right, Underpinning can be a rewarding cost effective solution to increase your property value.  As house prices soar, home owners are choosing to renovate unused spaces to maximize utilization.

The majority of homes have 8′ ceiling and tend to be unfinished.  Once you add your walls and mechanical, that height quickly shrinks creating a claustrophobic, minimal functioning space.

Benefits of Underpinning basements?

  • creates livable space by increasing the ceiling height
  • boosts the value of your property
  • presents an opportunity to upgrade the plumbing and electrical
  • improves the structural soundness of your home
  • accessibility to mechanics increased
  • the least expensive project to increase your SQFT – minimal intrusion as it only effects basement

The Stages of Underpinning Process

1. Demolition Work:

This involves the removal of all items from the basement, followed by the demolition of the existing floors, walls and other finishes. The purpose of this is to create a clear and clean working environment to start the lowering process.

2. Removing Concrete Floor:

If the concrete floor is more than 4” thick, power tools may be required. Utilities will be identified prior to the process of the concrete slab demolition.

3. Soil Excavation:

The necessary height is acquired by removing soil. Either by hand with wheel barrows or mechanical needs with the assistance of a soil belt.

4. Underpinning Sections:

Using city-approved engineering drawing, the existing basement will now be divided into vertical sections. These sections will be identified (1,2,3,4,- repeats). The number signify where the same numbered sections will have to be excavated. It is the underpinning teeth or sections that makeup the structural integrity of the underpinning.

5. Inspections:

Don’t compromise the integrity of your home. Perform regular inspections at various stages. This will make sure that the weight baring columns aren’t compromised. Throughout the structural excavation stages, a licensed engineer or city inspector has to sign off on the work done. This helps ensure that the basement lowering scope as done according to the local building codes.

6. Drains:

Basements are likely to take on more water than any other room in your home. The next step is the installation of your drainage system.

7. Waterproofing and Gravel:

Located below the ground surface, water leaks from the outside are not the only issues you have to worry about in a basement. Water may also seep up from the ground and cause damage. This is why proper waterproofing is so important .Once the basement has been dug properly and the new foundation has been set, the step in eliminating future drainage or water leakage problem is waterproofing. Installation of your system happens prior to the layering gravel on top of the soil.

8. Insulation and Radiant Floor Heating:

Located under the ground, the basement receives very little heat from the sun. Floors are cold and it can be expensive to heat up a basement.  Installing radiant heating will keep those floor toasy warm while providing a heat source to the rest of the room.  A great preventive measure to ward off dampness. 

9. Sump Pit and Sump Pump:

Massive rainfalls can overwhelm your existing systems, when the city sewers overflow.  Prevent basement flooding by installing a sump pit and pump diverting water to a designated spot.  Additional benefits include city incentives and rebates paid directly to you.

The last step is pouring the basement concrete slab.  Prior to pouring the concrete, it is important to double check the sewer and electrical are in place as these will be imbedded in the concrete and inaccessible after curing. The ground will be prepared with a layer of gravel and a waterproofing membrane, this keeps moisture from penetrating the concrete. After the concrete is poured, a special tool called a screed board is used to smooth out all the imperfections.

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