Canadian Woodworking

Flood proof your home

Author: Allan Britnell
Photos: Lead Photo by Dreamstime
Illustration: Len Churchill
Published: October November 2018
flood proof your home
flood proof your home

While you can’t entirely protect yourself from Mother Nature’s wrath, here are several steps you can take to help prevent flood damage to your home.


DIY Tips on How to Protect Your Home From Floodwaters

Setting aside your political views on whether climate change is a human-made problem or a natural cyclical phenomenon, there’s no denying that global weather patterns are changing. Here in Canada, one of the side effects has been the increased frequency and intensity of torrential rainstorms. If you live downstream from a major waterway, the flooding can be truly disastrous. Do some work now to avoid disaster down the road.

All about eaves

The key to preventing basement flooding is to keep water away from the foundation, and your eavestroughs and downspouts are your home’s first line of defense. Your eavestroughs should be cleared of debris at least twice a year (early spring and late fall) to prevent backups. If not, in heavy rains the water will just pour over the sides and down against the foundation. While you’re doing that, check to make sure that they’re all sloping towards the downspouts. The weight of leaves and winter ice can cause sections to sag. If that’s the case, they’ll need to be rehung.

They should be inspected even if you installed a gutter cover system, as those sometimes get clogged with matted leaves on top, or pine needles spiking through the drainage holes.

The downspouts should extend at least 4′ away from the foundation and discharge onto ground that’s sloping away from the building. Another option is to run the downspout into a rain barrel. If you go that route, make sure the barrel’s overflow pipe flows away from the home.

Many older rural homes have downspouts that connect directly to the municipal storm drain system. With older pipes, that’s just a disaster waiting to happen. These should be disconnected and extended so that they flow away from the building. Cover the ground-level connection with a PVC cap or concrete. Many municipalities have programs to help subsidize the cost of disconnecting downspouts.

While you’re at it, inspect the perimeter of your home and use exterior-grade caulking to seal any gaps around water, gas and power lines that breach the building envelope. This will help keep rain, bugs and drafts out of your wall cavities.

Getting good grades

The terrain around your property should slope away from the building on all sides so water doesn’t pool against the foundation. If not, you should build up the ground closest to your house to get it sloping away. If your house sits at the bottom of a hill or ravine, you may need professional advice on how to channel water around the building.

Asphalt and patio stones can’t absorb water, so the more of these “hard surfaces” you have in your yard, the less opportunity for natural drainage there is. Increase the amount of greenspace on your lot or use a porous material for the driveway and patio to help increase drainage.

Fighting floods

For many Canadians living close to major waterways, the potential for spring flooding is an annual cause for concern. If a major natural disaster occurs, various levels of government will pitch in to help, but you don’t want to feel helpless while waiting for aid to arrive.

If frequent flooding is a risk, you’d be wise to stock up on a private supply of reusable sandbags that you can fill as needed, or one-time use flood bags pre-filled with absorbent crystals that expand as they collect the water.

Basement windows should be above grade, but that’s not always the case. If you have window wells, the frame should extend above grade. Grade-level basement windows can be built up with wooden frames that are capped in aluminum then sealed with caulking.

There are also adjustable or custom-made watertight barriers you can install to protect ground-level windows and doors. (If the flooding reaches the height of main floor openings you’ve got bigger problems than water damage to your furniture.)

If your home has a sump pump, you’re strongly advised to invest in a battery backup system. After all, the torrential storms that can lead to flooding, also lead to power outages.

If flooding is imminent, turn off your power for the safety of your family and rescue or clean-up crews. Which warrants a reminder that if the power is off, your sump pump won’t work unless it has a fully charged battery backup system.

Finally, long before the flood waters rise, you should make a detailed list of the contents of your basement and take photos and videos of the rooms so you have a record for your insurance company.

Basement planning

Traditionally, Canadian basements were just a cool place to store food, and a dumping ground for your extra stuff. But as property values shot up, so did the value of that below-ground real estate. So now our basements are often the home entertainment centre, with all kinds of expensive electronics.

For starters, electronics and other valuables should be elevated off the ground as a preventative measure. The basement is also the last place you want to store important documents.

The basement is usually where we put our utility rooms to house the furnace, hot water tank and fuse panel or circuit breaker. If you are in a flood-prone area, it might be worth investing having your HVAC equipment elevated above the basement floor or suspended from the ceiling to reduce the risk of damage.

If you heat your home with oil, make sure the tank is securely fastened to the floor so that in the event of a flood it doesn’t tip over and add another toxin to the messy mix.

Weep not

Most homes have what’s known as a weeping tile system around the perimeter of the foundation, designed to channel water away from the walls. In the past these were made of clay, but modern systems use perforated plastic piping that slopes away from the foundation. In older homes, the weeping tiles may be clogged or nonexistent. The only fix is to excavate and replace.

Ideally, you’ll excavate all around the exterior, apply a waterproofing membrane to the outside of the foundation, and tie that into a new weeping tile system. Unfortunately, with narrow urban lots, exterior excavation is impossible. The alternative is to waterproof from the inside, and connect the drainage system to a sump pump (with a battery backup power supply) that will eject the water whenever the holding tank fills up.

Sewage backup

Having water seep into your basement is bad. Having sewage back up into your basement is the stuff of nightmares. If there’s a clog in the city sewer system, it can force sewage back into your home, leaving a nasty, toxic mess. A backflow preventer is a relatively simple device that allows sewage to flow out, but it seals shut if the flow is reversed. Many municipalities subsidize the cost of installing these units.

Some insurance providers will cover the cost of a preventive inspection of your waterlines, kitchen and bathroom fixtures, and even a camera inspection of your sewage outflow to make sure there aren’t any roots clogging the line.

Popping pipes

Sometimes it’s the water inside your house that becomes the problem. A burst pipe usually calls attention to itself pretty quickly. But a slow leak can do damage behind the walls for days or even weeks before it’s discovered. To help notify you of a leak as soon as it occurs, there are a number of leak-detection systems on the market.

Finally, educate everyone in your family on what to do if a clog or rupture occurs. Toilets and faucets should have shutoff valves on the inflow waterline so you can isolate the problem without cutting off the household water supply. For bigger issues, make sure the main water shutoff valve is easily accessible, and that everyone in the home knows where it is and how to use it.

Allan Britnell - [email protected]

A long-time freelance contributor to Canadian Woodworking, Allan Britnell is now the Editor-in-Chief of

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