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Ottawa Basement & Foundation Maintenance Checklist

A season-by-season checklist to keep your Ottawa basement dry. Our freeze-thaw winters and Champlain Sea “Leda” clay are hard on foundations, so a little upkeep each season prevents most wet-basement problems. Print it, stick it on the wall and tick off each task.

Spring, the highest-risk season

Spring melt over frozen, clay-heavy ground is when most Ottawa basements flood. Do these first.

Test your sump pump before the melt: pour a bucket of water into the pit and confirm it switches on and drains away. Test the sump pump’s battery backup so it works if the power drops during a storm. Clear snow and ice away from the foundation walls and window wells so meltwater drains away, not toward the house. Reconnect and extend downspouts so they discharge at least 2 m (6 ft) from the foundation. Clean gutters of winter debris so meltwater flows to the downspouts, not over the edge. Walk the perimeter: look for pooling water, soil that has settled against the foundation and any new cracks from freeze-thaw. Inside, check for damp spots, white efflorescence or water where the floor meets the wall (the cove joint) after the first big melt.

Summer, the best time for repairs

Dry conditions make summer ideal for grading and sealing work.

Re-grade soil so it slopes away from the foundation, the single best DIY fix for keeping water out. Seal any foundation cracks you flagged in spring; dry concrete is best for crack repair. Keep basement humidity around 50% or lower with a dehumidifier to control musty smells and mould. If you have a backwater valve, inspect it and clean debris off the flap so it can close properly. Make sure the air-conditioner condensate line and all downspouts discharge well away from the foundation. Trim shrubs and tree roots growing close to the foundation.

Fall, prepare for winter

Get ahead of freeze-up and the next spring melt.

Clean gutters again after the leaves drop so they don’t overflow against the foundation. Disconnect and drain garden hoses and confirm downspout extensions are in place before the ground freezes. Test the sump pump one more time heading into winter. Check the seals and weatherstripping on basement and egress windows; add window-well covers to keep snow and rain out. Do a final crack walk-around before the ground freezes so you have a baseline for spring. Confirm the yard still grades water away from the house after a summer of settling.

Winter, monitor and protect

Keep water and ice away from the foundation between thaws.

Keep snow cleared from against the foundation walls, window wells and the egress. Make sure the sump pump’s discharge line isn’t frozen or blocked. Keep the basement heated enough to prevent pipes freezing. Watch for roof ice-damming, trapped meltwater can find its way down into the walls. After a thaw day, check the basement for any new moisture or seepage.

When to call a professional

Maintenance handles the everyday; some signs mean it’s time for a proper inspection: cracks that are widening, horizontal or stair-stepped; water at the cove joint; recurring flooding; a floor drain or toilet that backs up in heavy rain; or a sump pump that runs constantly or never. See our 7 warning signs guide.

A backwater valve or sump pump may qualify for a City of Ottawa rebate, see the Residential Protective Plumbing Program.

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