Perils of Basement Renovation

If your house is not new, but old;
Remove any basement mold.
Image Credit: MS Office ClipArt: Basements, Buildings, Houses
2011 @ wobuilt.com

If the basement is used as a living space, it has to be safe, dry and healthy.

We never want to be the bearer of bad news when we do our renovations, but basements seem to be our nemesis (with regards to being the messengers of bad news). In cases of unfinished basements problems are easily identified, but in finished ones: many evils are covered up.

Originally most basements were designed for storage, unfinished utility rooms, coal storage; generally the walls were left unfinished and not insulated, making a wet basement not a huge problem. Later, the same basements were converted into living spaces. This is when a lot of problems started.

There are two main issues: water and water related structural ones. Wet basements are common, especially in older buildings. Most older homes do not have a working weeping tile system on the outside, which would drain the water away from the house. Water is allowed to reach the walls and put pressure onto them. Over time due to water and ice attacks the walls develop cracks and the water will seep through them. Some construction methods seem to hold up better than others, but there are no hard and fast rules.

It is quite possible that when the basements were converted that the walls were still in reasonable condition. Water damage can occur at any time. However, some basements we now encounter have horror stories to tell.

Once the water has access to the basement interior and is allowed to soak the drywall, mould will form and spread rapidly. Moisture ingress can be difficult to detect, especially in a dry spell, and unless there is evidence of water stains and exterior mold, home inspections can be mislead. Once found, we recommend that both drywall and studs are removed to allow a thorough mold remedial.

Water related structural problems can be found if the water has been allowed to seep through the wall for a long period of time. Concrete block work seem to be affected the most. The wooden spacers between each layer of block rot way and can form large gaps, potentially making the wall less stable.

The principle of fixing the water issue is relatively straight forward. You either keep it away from the wall from the outside, or let it come in and then divert it to a sump pump where it is ejected from the house. The choice of system and method will depend on the severity of the structural damage, where the water enters the building, the ease of being able to dig outside and if it is possible to trench inside due to choice of flooring and finishes.

However, there is a choice you cannot make: to do nothing. If the basement is used as a living space, it has to be safe, dry and healthy. Even if you decide to do the mold remedial and fix the structural issues, if you do not control the water, the problems will not go away. If anything they might become worse.


Martina Ernst
President/CEO
Wo-Built Inc. - Innovative Design and Build

Please, follow the links to find more information:

cmhc-schl.gc.ca: Renovation Fact Sheets: Renovating Your Basement for Livability
If you are planning a basement renovation, you should inspect your basement for possible problems.

cmhc-schl.gc.ca: Avoid Surprises: Renovating Your Basement — Moisture Problems
Moisture problems are caused by a buildup of a variety of water sources. Whether it comes from surface or ground water that leaks in, water that wicks up or water vapour that condenses, it must be controlled.

wobuilt.com/blog: Top Reasons to Do Kitchen and Bathroom Renovations