An insulation element is provided for installation in a gap of thickness G provided between two objects. The insulation element includes a body made from a thermoplastic polymer material. The body has a first face, a second face and a thickness defined between the first and second faces. The body is characterized by a semi permanently pre-installation thickness T1 where T1 is less than G. The body swells upon heating to a thickness T2 where T2 is greater than or equal to G so that the insulation element bridges the gap, engages the two objects and provides a spring rate of between 4.0 and 275.0 grams per square inch.