| Answer | Crossword Clue |
|---|---|
| insulants | insulating material, as used in building trades |
| insulant | insulating material, as used in building trades |
| tarpaper | A heavy paper impregnated with tar and used as a waterproofing material in building |
| limestones | A hard sedimentary rock, composed mainly of calcium carbonate or dolomite, used as building material and in the making of cement |
| sponges | Such a substance used as padding or insulating material |
| coquina | soft, whitish rock made up of fragments of marine shells and coral, used as a building material |
