Excavation around the house: How to maximize your work

Ensuring the foundation walls are waterproof

The tar sealant originally applied to the outside of the foundation walls below ground can be upgraded. There are three possibilities:

• A spray-on liquid elastomer coating; ideal for irregular surfaces, it forms a continuous rubber-based waterproof barrier.
• A roll-on adhesive elastomer membrane. It is elastic, durable and self-sealing, and resistant to small stones as well as slight shifting of the foundation.
• A drainage membrane. This is a dimpled-plastic sheet that is fastened to the foundation with concrete nails, and directly water straight down to the drain, preventing hydrostatic pressure on the walls. Combined with one of the membranes described above, it can act as a second barrier.

Insulating the basement walls from the outside

Unless your basement is already finished and insulated, excavation provides a good opportunity to insulate the foundation from the outside.

• Consult an expert on the subject. There are products available that meet the existing Quebec energy-efficiency requirements for residential construction. 
• This solution may increase the volume of your foundation walls, with a possible esthetic impact on the junction between the foundation and the exterior wall cladding.

Improving backfill quality

Problems with water pooling on your property can be exacerbated by poor backfill quality. Proper backfilling includes:

• A generous coating of gravel to properly cover the drain, covered in turn by:
• a layer of granular earth; and, above that,
• a layer of water-resistant soil, e.g., clay.

Replacing the water inlet and sewer lines

Replacing a water inlet and sewer line is usually expensive, because it has to be done in an emergency. So why not take advantage of the machinery and labour already being there, and save money?

1. If there is flooding, put safety first

Make sure there is no risk of electrocution.

• Wear rubber boots.
• Cut the power to the flooded parts of the house.
• Unplug all appliances and other electrical devices there.

2. Report the incident

First your insurer, then the city, and then other resources!

Your insurer

Report the damage to your insurer immediately. Visual evidence (photos, video) can be very useful to help the insurer rapidly assess the situation. If, for example, you have home insurance with CAA-Quebec and you took the “Water damage” option when you bought your policy, you are covered for water damage. Get authorization quickly to proceed with removal of framework, insulation, as well as wall and floor coverings.

Municipality and utilities

Report the incident, if need be, to the municipality as well as to any utilities/providers affected (e.g., Hydro-Québec, Gaz Métro, phone company).

3. Proceed with post-disaster work

Quick action (within 48 hours) is required to limit the damage. For best results, entrust the work to experts. This will ensure that mould does not proliferate on surfaces and in voids, crevices, etc. If you decide to mop up the initial damage, make sure you wear rubber gloves and boots, a breathing mask, and safety glasses to guard against contamination.

Entrust the clean-up job to an expert firm…

It is highly recommended that you hire a reliable post-disaster clean-up company, especially if decontamination is needed. They have the knowledge and equipment necessary to act effectively and limit the impacts. If necessary, they will demolish water-damaged gypsum wallboard and flooring to speed up the drying-out process.

Once the basement is cleaned, you can start rebuilding yourself, if you want. But consider the benefits of doing business with a company that has a general contractor’s licence: the work will be guaranteed, completed in a timely manner, and compliant with the required codes, with your home’s full property value maintained. 

CAA-Quebec Residential Advisory Services are there to help you find the right contractors for the job, and to answer any questions you may have in case of doubt!