Novel constructions and methods

Claim 2

The construction of claim 1 wherein the surfaces of said thermal barrier which are in contact with said frozen surface, are vapor impermeable.

Claim 3

In a construction supported on a frozen surface normally subject to periodic thawing, the improvement which comprises in combination; a continuous thermal barrier interposed between the base portion of said construction and said frozen surface; said tHermal barrier having a peripheral margin extending outwardly beyond the outer perimeter of said base portion a distance at least equal to the maximum depth to which periodical thawing of said frozen surface normally occurs; said thermal barrier being in contact with said frozen surface; said thermal barrier being a composite of at least two layers of rigid cellular polymers having different densities; whereby said frozen surface supporting said construction is maintained permanently frozen.

Claim 4

A construction according to claim 4 wherein said barrier comprises a composite of; (1) a lower layer of a rigid cellular polyurethane having a density up to about 10 lbs./cu.ft. and (2) an upper layer of rigid cellular polyurethane having a density from about 10 lbs./cu. ft. to about 60 lbs./cu. ft.

Claim 5

A construction according to claim 5 wherein said barrier comprises a composite of; (1) a lower layer of a rigid cellular polyurethane having a density up to about 10 lbs./cu. ft. and (2) an upper layer of rigid cellular polyurethane having an overall density of from about 10 lbs./cu. ft. to about 60 lbs./cu. ft. said upper layer having an integrally formed non-cellular skin.

Claim 6

A construction according to claim 5 wherein the surfaces of said thermal barrier which are in contact with said frozen surface, are vapor impermeable.

Claim 7

A construction according to claim 5 wherein said peripheral margin of said thermal barrier projects downwardly through said frozen surface subject to periodic thawing to a point in the sub-strata which is not subject to periodic thawing.

Claim 8

In a construction supported on a frozen surface normally subject to periodic thawing, the improvement which comprises in combination; a continuous thermal barrier interposed between the base portion of said construction and said frozen surface; said thermal barrier having a peripheral margin extending outwardly beyond the outer perimeter of said base portion a distance at least equal to the maximum depth to which periodical thawing of said frozen surface normally occurs; said thermal barrier being in contact with said frozen surface; said thermal barrier being a composite of rigid cellular polymers having differing compressive strengths wherein the major load bearing areas of said composite thermal barrier are fabricated from rigid cellular polymer of relatively high compressive strength and the non-load bearing areas of said composite thermal barrier are fabricated from rigid cellular polymer of lower compressive strength; whereby said frozen surface supporting said construction is maintained permanently frozen.

Claim 9

A construction according to claim 10 wherein said peripheral margin of said thermal barrier projects downwardly through said frozen surface subject to periodic thawing to a point in the sub-strata which is not subject to periodic thawing.

Claim 10

A construction according to claim 10 wherein the surfaces of said thermal barrier which are in contact with said frozen surface, are vapor impermeable.

Claim 11

A construction according to claim 10 wherein the upper layer of the composite thermal barrier forms the floor of the supported construction.

Claim 12

In a method for erecting a construction upon a frozen surface subject to periodic thawing, the improvement which comprises; fabricating a continuous thermal barrier upon said surface while said surface is in frozen condition, whereby said frozen surface is maintained permanently frozen; and positioning the base portion of said construction upon the exposed surface of said thermal barrier so that a peripheral margin of said thermal barrier extends outwardly beyond the outer perimeter of said base portion a distance at least equal to the maximum depth to which periodical thawing of said frozen surface normally occurs.

Claim 13

A method according to claim 13 wherein the thermal barrier is fabricated by applying a rigid cellular polyurethane forming mixturE upon said frozen surface, and allowing said mixture to foam in place.

Claim 14

A method according to claim 14 wherein the thermal barrier is fabricated by covering said frozen surface in the frozen state with a vapor impermeable material; placing a rigid cellular polyurethane forming mixture upon said vapor impermeable material; and allowing said mixture to foam in place.

Claim 15

A method according to claim 14 wherein the thermal barrier is fabricated by: covering said frozen surface in the frozen state with a vapor impermeable material; placing a low density rigid cellular polyurethane foam forming mixture upon said vapor impermeable material; allowing said mixture to foam in place; and bonding a high density polyurethane foam to the upper surface of said low density polyurethane foam.

Claim 16

A process for maintaining in the permanently frozen state a frozen surface which is normally subject to periodic thawing, which process comprising covering said surface, while in the frozen state, with a continuous layer of a thermally insulating rigid cellular polymer, the peripheral margin of said layer extending downwardly through said surface subject to periodic thawing to a point in the substrate which is not subject to periodic thawing.

Claim 17

In a construction supported on a frozen surface normally subject to periodic thawing, the improvement which comprises in combination; a continuous thermal barrier interposed between the base portion of said construction and said frozen surface; said thermal barrier having a peripheral margin extending outwardly beyond the outer perimeter of said base portion and projecting downward through said frozen surface subject to periodic thawing to a point in the sub-strata which is not subject to periodic thawing; said thermal barrier being in contact with said frozen surface; whereby said frozen surface supporting said construction is maintained permanently frozen.