Tail Beam - Joist supported by header at both ends, from a header in a floor opening to the sill header.

Terra Cotta - A mixture of sand and baked clay commonly used to make pipe for sewage disposal systems. A mixture of sand and baked clay used to form a shingle used on certain styles of architecture.

Terrazzo - A colorful flooring material made of cement and marble chips or certain stones. After the floor has hardened it is ground and polished to a smooth and durable finish.

Thermopane - Two or more sheets of glass set apart from one another with a vacuumed space between to prevent condensation and reduce heat loss.

Thermostat - An automatic device to control heating or cooling.

Three-way Switch - Electrical switches installed in pairs to allow a light or appliance to be controlled from to locations.

Threshold - The wooden or metal strip directly beneath an exterior door. Some have an added rubber or plastic strip feature for better weatherstripping.

Throat Cut - The notch cut into rafters to allow proper seating on the plate.

Timber - Large wooden boards used in creating the structure of a wall.

Tongue and Groove - A type of wooden siding with the edge of one board fitting into the groove of the next.

Top Rail - The upper rail of the top sash of a double hung window.

Traffic Plan - A plan of room and door placement designed for convenience of movement in normal everyday activities.

Transom - A small window just above a door.

Trap - A plumbing device preventing sewage odors from entering the house.

Tread - The horizontal portion of a step, usually with a rounded edge , or 'nosing' which overhangs the riser.

Trellis - A system of horizontal joists supported on posts, designed to support growing plants.

Trimmer - Two joists or rafters spiked together and run parallel to joists or roof rafters to supply needed support to a floor, ceiling or roof opening.

Truss - A framework for supporting a roof.

Turret - A small tower, often at the corner of a building. Common in Queen Anne Styles among others. A turret is a smaller structure while a tower begins at ground level.