One of our hall of shame photos, dimple board drainage down into a drain tile system.

We started to see this product over the last five years grow very popular along with heavy-duty plastic sheets to help channel the water into the floor. Most of these are made with HDPE (high-density polyethylene) made from oil.

Standard polyethylene plastic sheeting (like standard poly rolls) for indoor basement waterproofing or vapor barriers presents a significant fire hazard and violates most building codes. Because standard poly is petroleum-based, it can melt and burn rapidly if exposed to a flame.

The International Residential Code (IRC) dictates that any exposed plastic used as an interior finish or vapor barrier must be flame-retardant.

Minnesota Building Code 26 (2020) goes into it a litte bit but we might see changes in the next edition. It looks like your ok if you have 1" of concrete over it. (this only talks about foam insulation).

2603.4.1.1 Masonry or concrete construction.



A thermal barrier is not required for foam plastic installed in a masonry or concrete wall, floor or roof system where the foam plastic insulation is covered on each face by not less than 1-inch (25 mm) thickness of masonry or concrete.

Is this a code violation?