Can I put rigid insulation under patio pavers, and should I have a permeable system right against the house?
I am considering replacing the patio outside my walk out basement of my 1959 house in northeast Ohio (zone 5). I would like to put rigid insulation under the new patio to help keep the uninsulated floor slab inside the house a little warmer, similar to a frost protected foundation. In a perfect world I would also like to have the new patio be permeable to minimize rain water runoff. However I ran across a publication from the state of Minnesota that recommends a minimum distance between a permeable pavement installation and a building foundation. So I have several questions:
-Is this a concern for small residential patios?
-Is there insulation available that would provide rainwater permeability as well as thermal protection?
-If I don’t try to have a permeable installation, could I use standard rigid insulation under pavers, or would a concrete patio be better with rigid insulation?
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Replies
Hallie,
This is not a good location for permeable pavers. It's a good idea to direct rainfall and snow melt away from your foundation.
If I were detailing this patio, I would prepare the subgrade by compacting gravel. The gravel would slope away from the building. On this prepared gravel I would install a layer of rigid foam, followed by a concrete slab. Again, the slab should slope away from the building.
On top of the slab, you can put any kind of pavers you want.
Love the advice here!
We’re planning a patio for our walkout basement under a deck that has the Trex Rainescape rain diversion system. It’s on the north side of the house, so, lots of shade, BUT is never damp for long periods of time.
There’s already 10-12” of compacted gravel (yay!).
The good news is, that this surface will see little sun and rain, so fading may be less of an issue. Also would like an even surface as we’ll have grandparents visiting, so minimizing tripping hazards.
From an environmental impact, is there a paver that’s recommended? Stone?
- Wayne