08/26/2026
What even is a "Ground Roof"?
When you think of a roof, you probably look up. But when protecting old stone foundations, the most crucial roof is actually underground!
In traditional Canadian home renovations, subsurface water pooling and intense freeze/thaw cycles are public enemy #1 for rubble stone foundations. Without proper intervention, water saturates the soil against the foundation, freezes, expands, and exerts massive thermal pressure. This leads to structural cracking, mortar failure, and wet basements.
A Ground Roof is an advanced subsurface water management and insulation assembly installed horizontally around the perimeter of a building. By pairing horizontal rigid insulation with an impermeable water-shedding membrane or dimple membrane, a sloped gravel bed, and perforated weeping tile, it creates a subterranean umbrella. It directs water 5+ feet AWAY from the foundation wall before it can ever sink near your footing.
We are currently implementing custom Ground Roof assemblies on two of our projects. By excavating a 2′ deep by 5′ wide perimeter trench, laying down precise 10% drainage slopes, extending vertical & horizontal XPS insulation boards, and installing sealed EPDM membranes and daylighted weeping tiles, we are permanently stabilizing these rubble stone foundations. 👊
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