Flood Resilience - How to Build More Resistant Houses

We can all recall images of people shocked at finding their homes completely destroyed as a result of major flooding. It happened in Montréal and Toronto in 2024, Baie-Saint-Paul in 2023, Sainte-Marthe-sur-le-Lac in 2019, Montérégie in 2011, and the list goes on. While once a rare occurrence, major flooding is becoming increasingly common. As a result, many homeowners are coming to terms with the fact that their homes weren’t built to withstand such natural forces.

Mother Nature is all-powerful, and homes are small and fragile in comparison, especially when exposed to extreme weather patterns. Despite that, there are ways to stack the odds in your favour and improve your home's resistance and resilience. At every step of a home renovation or build, with waterproofing in between, choices are made that can have a significant impact in critical times. 

You may be asking yourself:

• Is my house in a flood-prone zone?

• Can my house flood even though it’s nowhere near a body of water?

• How can I waterproof every inch of my house, top to bottom?

Let’s take a closer look.

Flood Mitigation: How to Increase Flood Resilience

The Association des professionnels de la construction et de l’habitation du Québec (APCHQ) issued a press release (French only) on August 15, 2024, highlighting the importance of flood-proofing residential buildings. Is your house sufficiently waterproofed to prevent water from coming in? Let’s take a look at the different contributing factors.

Foundation and Basement Waterproofing 

Oftentimes, water seeps inside dwellings via the basement or crawl space. During many flood events, said spaces are first affected by rising water levels. Foundation cracks and poorly sealed openings (doors and windows) are little gateways through which water can infiltrate, damaging your home.

Here’s everything you should know about waterproofing your basement and foundation, including renovation work to stack the odds in your favour:

• Steps for Keeping Your Basement Dry and Waterproof

• Reasons, Methods, and Products to Waterproof Your Foundation

Waterproof Exterior Siding

At times, flood water rises, meeting first-floor landings, and in worst-case scenarios, the floors above. Hence, waterproofing your exterior siding is of utmost importance.

If your exterior siding already has a decent protective coating, make sure to maintain it adequately to prevent setbacks.

On the other hand, if the existing siding isn’t suitable, waterproofing measures should be at the top of your priority list when choosing your next siding.

Here’s a guide detailing the different types of exterior siding: Which Exterior Siding Material Should You Choose?

Waterproof Roofing

During periods of heavy rainfall, water is likely to leak through the roofing, and subsequently into your house. Improving the resilience and resistance of homes also means preventing possible floods as a result of a poorly sealed roof. Make sure your roof is in tip-top shape, carry out any necessary repairs right away, and if you choose to re-roof, get a waterproof roofing material.

• Roof Sealant: A Necessary Additional Waterproofing Measure?

• Which Roofing Material Will Best Suit Your Needs?

• When Should You Change Your Roofing?

Seal Doors and Windows (House and Garage)

Windows come in handy to peek outside and check the weather in the safety and comfort of your home. On the other hand, if the openings are poorly sealed, rainwater can disrupt this reassurance and cause significant damage to your home.

Here’s everything you should know about sealing doors and windows to protect your home from floods: 

• How to Make Windows More Watertight

• How to Seal a Front Door

Landscaping: How to Improve Rainwater Drainage Systems

For a few years now, it has become apparent that one of the contributing factors to flooded buildings is that residential landscaping and urban land use sometimes fail to adequately address the rapid rise of surrounding water levels. The use of unporous materials like concrete makes it so that water builds up and flows freely until hindered by obstacles or porous materials.

Urban planners, landscape architects, and other land-use experts have to find solutions tailored to streets and green spaces surrounding residential buildings.

Is the landscaping around your house optimized to absorb rainwater before it seeps inside your foundation? If you're not sure, you might want to look into turfstone pavers.

Flood-Proof Your Yard and House: Pumps, French Drains, and Other Options

Several systems and landscaping solutions are designed to drain rainwater away from your home, channelling it toward a porous area. Dry wells, French drains, submersible pumps, and gutters come to mind. Moreover, if you’re not already familiar with the concept of a water table, read up on it.

Check out this article for more information about French drains:

• What Is a French Drain?

At-Risk Houses: What Is a Flood-Prone Zone? 

The truth of the matter is, that flood-prone zones are now spread out over and less pinpointed than they once were. People who live near bodies of water are particularly affected, but floods also occur as a result of ineffective landscaping, leading to stormwater build-up. Typically, these include damaged aqueducts or torrential downpours that fail to drain properly, stagnating or rising.

That’s what happened in August of 2024 in Montréal; a small leak caused a tremendous headache for local authorities and homeowners nearby.

What Criteria Determine If a House Is in a Flood-Prone Zone?

According to the Climate Change Institute, in Canada, more than 1.5 million houses are built in flood-prone areas. The criteria vary from one province to the next, and the more flooding there is, the more homes fit into said category. Homeowners can find more province-specific information on FloodSmart Canada.

Flood Maps: How Can You Find Out If Your House Was Built in a Flood-Prone Area?

There are several ways for you to check whether your house is standing in a flood-prone territory. First, check your home’s certificate of location. However, note that the information provided might not be up-to-date if the certificate of location you have is old. In any case, you can request a new certificate of location, or consult flood maps online.

Also, the Government of Canada has its own flood mapping page, made available to the public. 

Is There Funding for Renovating a Flood-Prone Property? 

Yes! Since desperate situations seemed to have multiplied over the last few years, different provincial governments across the country now provide financial support for those seeking to flood-proof their homes.

The Canadian government launched the National Disaster Mitigation Program (NDMP), sending funding to provinces and territories. Citizens can’t apply, but funds are allocated in different ways such as selected by one’s provincial government.

In Montréal, citizens have access to the RénoPlex Program, allowing building owners to renovate for the sole purpose of weatherproofing.

After each natural disaster, funds are also provided to persons affected to help rebuild infrastructure according to a building code tailored to a specific situation.

How Can You Mitigate Flooding?

In life, a lot is out of our control, especially rising water levels, which can be a flooding hazard. That said, homeowners can stack the odds in their favour to make it out unscathed—or nearly so.

As a homeowner, you’re likely doing everything in your power to ensure your home is weatherproof and resilient by following the tips and tricks detailed in this article.

As a citizen, we have to encourage our municipalities and government authorities to promote flood mitigation projects by opting for urban and rural land planning solutions that are tailored to region-specific risks of flooding, such as creating sponge parks, limiting the use of concrete when possible, upgrading municipal sewer systems, and redirecting rainwater.

Who Can Inspect My House for Waterproofing?

If you’re looking to have the overall state of your home assessed, you can hire a building inspector. They will carry out a general home inspection, focusing on the waterproofing aspect if requested.

You can also proceed one step at a time, consulting experts in foundation, roofing, and windows and doors.

Additional Tips & Tricks to Protect Your Home from Floods 

• Assess the state of your plumbing system to ensure that it can withstand rising water levels (sewer backup).

• Check whether your gutters are in good condition, ensuring that rainwater is channelled toward the downspout instead of stagnating.

• If your property has negative grading, fix it.

• Check out this article: 6 Ways to Deal with Flooding

FAQ About Floods 

When is the risk of flooding the highest?

The primary cause of flooding in Canada is heavy rainfalls and melting snow in the spring. That being said, climate change makes it so that Mature Nature throws our way weather that’s increasingly disastrous during the summer and throughout the year too. Hence, a lot of buildings flooded in Montréal in August 2024.

The tail end of winter is also closely monitored by authorities in charge to prevent flood-related damage, but the surveillance period tends to stretch for months on end.

What are the consequences of flooding for homeowners?

First, deteriorating, if not, completely destroyed buildings. Next, renovations are called for, if not relocating, should repairing the damage done be ineffective. Oftentimes, insurance premiums increase and reimbursement thresholds decrease. Lastly, the sense of safety and security felt by citizens is hanging on by a thread.

Are there more floods than before in Canada?

With rising water levels and increasing heavy downpours (atmospheric river, hurricane remnants) affecting coastal regions, more floods have been reported across the country.

What are flood resilience measures for homes built near bodies of water?

Here are some tips and tricks to protect homes built near bodies of water:

• Upkeep the French drain circling the foundation

• Regularly inspect the submersible pump

• Seal all openings below water level (as per the National Building Code)

Why was my home flooded even though it’s not in a flood-prone zone?

Besides flooding resulting from overflowing rivers, other scenarios can lead to significant amounts of water inundating buildings. Below are some examples:

• Overflowing stormwater drain

• Aqueduct system failure or breakage

Over the last few years, we’ve been privy to several of the two above-mentioned scenarios in Montréal, including the unexpected water main break that washed out a large part of the Ville-Marie borough in August 2024.