A one-component foam formulation contains a pre-polymer and a blowing agent, the pre-polymer being the reaction product of a polymeric polyol component having an average hydroxyl functionality in a range of 2.3 to 2.85 hydroxyl functionalities per molecule as determined using ASTM D4274-11 (method D); and where the polymeric polyol component has an effective average molecular weight in a range of 4500 and 10000 grams per mole, one or more than one type of chain extender molecule having 3 to 6 carbon atoms and 2 to 4 reactive functionalities selected from a group consisting of hydroxyl and amine functionalities per molecule, a polyisocyanate having a functionality in a range of 2.1 to 3.0 —NCO functionalities per molecule as determined by ASTM D7252-06(2011)e1; and a catalyst.