Patent ID: 8555588

Claim:
An insulating sidewall form for concrete, which form is stackable horizontally and vertically above and below with other like forms, comprising two rectangular foam plastic sidewalls making up an inner sidewall and an outer sidewall the inner and outer sidewalls each having: an interior surface, such that when the two sidewalls are positioned to create the form, the interior surfaces of the sidewalls form a plurality of vertical cavities and vertical slots, a flat exterior surface, the inner sidewall further having: a first horizontal surface having a raised portion along the interior surface and a non-raised portion along the exterior surface, a second horizontal surface having a non-raised portion along the interior surface and a raised portion along the exterior surface, and opposed vertical surfaces, a first vertical surface having a tongue and a second vertical surface having a complimentary groove, the outer sidewall further having: a first horizontal surface having a non-raised portion along the interior surface and a raised portion along the exterior surface, a second horizontal surface having a raised portion along the interior surface and a non-raised portion along the exterior surface, the raised and non-raised portions being arranged so as to allow attachment of the upper surfaces of one form with the lower surfaces of like forms, and opposed vertical surfaces, a first vertical surface having a tongue and a second vertical surface having a complimentary groove, the tongues and grooves of the form being so arranged that each end of the form will contain one tongue and one groove so as to allow end-to-end attachment of like forms, the form containing a plurality of ties connecting the sidewalls and maintaining the sidewalls at a constant distance from each other.