What is negative grading and why is it a problem after a renovation?

Negative grading is when the ground slopes towards your home's foundation instead of away from it. Renovations often cause this by disturbing the original landscape. It's a major problem because it channels rainwater directly against your foundation, leading to water pressure, leaks, and potential flooding in your basement or crawlspace.

My new patio seems to be causing water to pool by my back door. What should I do?

This is a common issue caused by new, non-porous surfaces. The patio is likely preventing water from absorbing into the ground and may have a slight negative slope towards your home. The best solution is to install an integrated drainage system, such as a catch basin or a French drain, to intercept the water and redirect it safely away from your foundation.

Do I need a permit to fix my lot grading in the Lower Mainland?

It depends on the scope of the work. Minor re-grading with topsoil may not require a permit. However, more significant work, especially involving retaining walls or extensive drainage systems, often requires a permit from your local municipality (e.g., Surrey, Burnaby, Vancouver). A professional drainage contractor can advise you on the specific requirements for your project.

How far away from the foundation should downspouts discharge water?

As a rule of thumb, downspouts should discharge water at least 6 feet (approximately 2 meters) away from your foundation. Simply letting water out at the base of the wall is one of the most common causes of foundation water issues. Extensions can be added to direct water further out, or they can be connected to an underground pipe that carries the water to a safer location.

Can a new garden bed against my house really cause drainage problems?

Yes, absolutely. A raised garden bed placed against your foundation can act like a dam, trapping water and saturating the soil directly next to your home. This constant moisture can compromise your foundation's waterproofing and lead to leaks. In our experience, it's always better to locate garden beds several feet away from the foundation or install a protective drainage barrier between the bed and the house.

Lot Grading Problems After BC Home Renovations: How

Drainage · 10 · 2026-03-31

Discover how home renovations in BC can lead to serious lot grading and drainage problems. Learn to identify issues like negative grading and protect yo...

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