Posted by: Karim Ali
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How to Maintain and Repair a Stone Foundation in Ottawa
Stone foundations are common in older homes in Centretown, The Glebe, and other historic Ottawa neighbourhoods. While they can last over 100 years, they need proper care to stay solid.
If you own a home with a stone foundation, or you’re thinking of buying one, knowing how to maintain and repair it can save you time, money, and major headaches. In this blog, I’ll explain how to keep your foundation strong, when to call a professional, and how much repairs typically cost.
How to Keep a Stone Foundation in Good Shape
Unlike modern concrete foundations, stone foundations require ongoing maintenance to prevent major repairs. Here’s what you can do to extend its life:
- Keep Water Away from the Foundation
- Check that your yard slopes away from your home to prevent water pooling.
- Make sure gutters and downspouts direct rainwater away from the foundation.
- Keep basement windows sealed to avoid leaks.
- Inspect for Moisture and Cracks
- Look for damp spots or puddles in your basement after heavy rain.
- Check for white, powdery residue (efflorescence) on the walls—this means moisture is moving through the stone.
- If you see crumbling mortar, it might be time for repointing.
- Avoid Using the Wrong Mortar
- If you need to repair gaps, always use lime-based mortar, not modern cement.
- Cement is too rigid and can cause further damage by restricting natural expansion and contraction.
- Install a Sump Pump if Needed
- If your basement regularly gets wet, a sump pump can help remove water before it causes serious damage.
- Consider a model with a battery backup to keep it working during power outages.
When to DIY vs. Call a Professional
DIY Repairs:
- Small cracks in the mortar.
- Minor repointing (if you have experience).
- Improving drainage around your home (make sure downspouts are discharging water 6ft+ away from the home, and that soil has a visible grade away from your house).
Call a Professional If:
- You see large gaps, shifting stones, or bowing walls.
- Water is seeping through even after making exterior drainage improvements.
- The basement has persistent humidity or musty smells, indicating deeper moisture issues.
Preventing Future Stone Foundation Problems
Once your stone foundation is repaired, keeping up with basic maintenance will prevent further issues.
- Monitor Your Basement Regularly: Look for new cracks, moisture buildup, or crumbling mortar every few months.
- Check Gutters & Drainage Every Season: Make sure rainwater flows away from the foundation, not toward it.
- Seal & Repoint as Needed: If you see small mortar gaps, fix them before they turn into bigger issues.
That's All
Owning a home with a stone foundation in Ottawa’s older neighbourhoods comes with extra responsibility, but with the right care, these foundations can last another century.
If your foundation has minor cracks or moisture issues, taking early action will save you money and stress in the long run. For major repairs, always consult a professional to avoid making the problem worse.
Thinking of buying a home with a stone foundation? Make sure to get a foundation inspection before finalizing your purchase.
Bonus tips
1
Keep Snow & Ice Away from the Foundation
In winter, don’t let snow pile up around the base of your home, as melting snow can lead to moisture issues.
2
Ventilate Your Basement Properly
If your basement is too humid, consider adding a dehumidifier to reduce moisture buildup and protect the mortar.
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