Thoughts on using Form-a-drain in place of interior and exterior drain tile?
Emel
| Posted in General Questions on
Our build is slab-on-grade with footings and 4’ stem walls. Currently, our build specifies the use of form-a-drain around the entire perimeter and an interior passive sump and radon mitigation system that drains to daylight. In the past, I’ve read internal and exterior drain tile should be kept separate and not connected. Because form-a-drain does connect interior drainage to exterior, should we have additional drain tile placed on the exterior that is not connected to the system and runs to daylight on its own as well?
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Replies
Seems to me this product has been around for some time now and has not been wildly successful.
Too my mind when the market rejects a product, whatever benefits it is offering they must not be worth the product’s other costs.
Walta
Thank you. I’m thinking that as well but our builder likes to use it. If we were to go with it, do you think the form a drain would be enough by itself or should have an additional exterior traditional drain tile installed around the perimeter as well? I’ve always heard external and internal drain tile systems should not be connected and that’s what form a drain does through the footing. We also live in a very wet area where perched water can be an issue during rainy seasons.
Groundwater doesn't care if it's inside your foundation perimeter or outside it; I have always specified both interior and exterior footing drains, connected in one or more locations. Form-a-Drain seems like a good product, but like many designers and builders who live in high-radon areas, I like for my footing drains to double as radon evacuation pipes, which require them to be sealed below the vapor retarder.