Distortion-free vinyl siding

Door panel construction

Double top chord

Double-walled panel for building

Dowel strip for bent-up bars

Dowel strip for web reinforcement

Dry cast block arrangement and methods

Dry set block wall building system

Dry stackable block structures

Dry-cast concrete block

Dry-cast concrete blocks and manufacturing process therefor

Dry-stackable masonry unit and methods of manufacture and use

Drywall backing apparatus and method of installing same

Drywall construction method and means therefor

Drywall exterior corner bead

Duct terminator

Durable edge ceiling board