Asphalt shingle with foamed asphalt layer under tabs

DETAILED DESCRIPTION We claim: 1.
An improved asphalt shingle comprising an asphalt shingle having a headlap portion and a normally exposed tab portion, with the improvement of a layer of foamed asphalt substantially covering an underside of the tab portion, the layer of foamed asphalt being of sufficient thickness at least at a free end portion of the tab portion to provide an enhanced relief effect when the shingle is installed on a roof, said free end portion of the tab portion being an end portion thereof remote from said headlap portion as distinct from an end portion thereof attached to said headlap portion.
2.
An asphalt shingle as claimed in claim 1, wherein the foamed asphalt layer is a continuous layer.
3.
An asphalt shingle as claimed in claim 1, wherein the foamed asphalt layer is a discontinuous layer.
4.
An asphalt shingle as claimed in claim 1, wherein the foamed asphalt layer is a plurality of spaced, parallel continuous strips.
5.
An asphalt shingle as claimed in claim 1, wherein the foamed asphalt layer is a plurality of spaced, parallel discontinuous strips.




Description:
TECHNICAL FIELD This invention relates generally to asphalt shingles, and more particularly to asphalt shingles having an extra layer of material on the underside of the tabs to provide an enhanced relief effect on a roof.
BACKGROUND ART U.
S.
Pat.
Nos.
4,188,763 and 4,195,461 disclose asphalt shingles wherein a layer of spheres of expanded polystyrene is provided on the underside of the tabs.
The expanded polystyrene spheres are expensive, hard to obtain, and difficult to process.
DISCLOSURE OF INVENTION In accordance with the invention, conventional asphalt shingles are provided with an additional layer of foamed asphalt on the underside of the tabs.
The additional layer may be continuous or discontinuous.
BRIEF DESCRIPTION OF THE DRAWINGS The invention is hereinafter more fully described with reference to the accompanying drawings in which: FIG.
1 is a view of the underside of a shingle constructed in accordance with the invention; FIG