Carpentry, Doors, Windows and Joinery
What this domain tests
This domain tests timber defects and seasoning, joinery names, door and window types, standard sizes, hardware, and the difference between the opening size and the shutter size.
Core rules and concepts
- Seasoning reduces moisture to about 12-15%, preventing warp, bow, cup, twist, shakes and splits.
- Joints: mortise and tenon for frames, dovetail for drawers, halving for crossing members, bridle and housing joints in framing.
- Door opening commonly 1.0 × 2.1 m or 0.9 × 2.0 m; shutter 35-40 mm thick; frame (chowkhat) section 100 × 63 mm.
- Members: stile (vertical), rail (horizontal), panel, mullion (vertical divider), transom (horizontal divider), architrave and threshold.
- Types: panelled, flush, glazed, louvered, wire-mesh; windows should give about one-eighth to one-tenth of the floor area as daylight opening.
- Holdfasts of MS flat are embedded in masonry to fix the frame; hinges, tower bolts, aldrops and mortise locks complete the fittings.
Worked example
Timber for a door frame in a 1.0 × 2.1 m opening with 100 × 63 mm section: two verticals of 2.1 m = 4.2 m, one top rail of 1.0 m = 5.2 m running length. Volume = 5.2 × 0.100 × 0.063 = 0.0328 m³, that is about 0.033 m³, say 0.035 m³ allowing wastage. Note the section is taken in metres before multiplying.
Traps that cost marks
Quoting door size as shutter size rather than clear opening; measuring the frame in running metres and charging it as cubic metres; forgetting wastage; naming a dovetail joint where a mortise and tenon belongs.