6 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boats, Dock Flotation, Carving, Soundproofing, Filling Voids, and Insulation (1 Gallon Kit)

Works great for my taxidermy molds Expands roughly 4 times liquid amount and is rock solid ( 6lb )

I used this product to pour through a small hole into an area that an animal was attempting to dig under my deck. It expands pretty rapidly and you need to get it poured as fast as you can after mixing it. You have maybe a 60 second working time before it takes off. It expands very rapidly and voluminously. It filled the area with decently hard cured material. Just don't put it someplace fragile and confined, it will very happily push out thin wood on its way to full expansion. The end material seems acceptably durable. It builds a thin skin on itself and it's not easy to rip apart or dislodge. The resultant material also sticks aggressively to anything, so make sure you are ok with that. Also, don't get the pre-cured material on your hands; it sticks extremely well to human skin and it will be a pain to get off. Overall a great product for filling spaces!

Worked great. Easy to mix, poured well, and got into all the holes. I had an hole in the base layer under some concrete that also has pavers on top. The concrete has shifted and no matter how much sand I used to backfill the cracks- the pavers keep shifting as well. I used this, and after a heavy rainy season, the pavers and concrete still have not moved.

Works extremely well!

This is good stuff, not soft, squishy foam. Very high density and tough