Wall linings
Wall lining depth and floor area lost: dot and dab against GypLyner
- where
- dot and dab lining depth (mm)
- dot and dab cavity (mm)
- board thickness (mm)
- GypLyner lining depth (mm)
- GypLyner cavity or offset (mm)
- floor area lost, dot and dab (m²)
- length of wall lined (m)
- floor area lost, GypLyner (m²)
Explain this equation
Compares how far a dot and dab lining and a GypLyner framed lining stand off the wall, and how much floor area each takes from the room.
cd is the compressed dab thickness, cg the GypLyner cavity or offset from the wall to the back of the board, and t the board thickness. Td and Tg are the total lining depths. Multiplying by the length of wall lined P, and dividing by 1000 to turn millimetres into metres, gives the floor area lost, Ad and Ag.
A lining is just a cavity plus a board, so the depths add; the floor area lost is a thin strip along the wall.
Sense check: dot and dab with 12.5 mm board is about 22 mm deep; GypLyner at its minimum is about 37 mm. On 14 m of wall that is roughly 0.3 m² against 0.5 m².
Watch out: the true cavity follows the worst part of the wall, so measure it before setting out door linings.
Compares how far a dot and dab lining and a GypLyner metal-framed lining stand off the wall, and the floor area each takes from the room.
Enter your values to see the result.
Good to know
British Gypsum DriWall Adhesive dabs are 50–75 mm wide, 250 mm long and 10–25 mm thick when the board is pressed home; the standard DriLyner Dab specification is a 10 mm nominal cavity. GypLyner Single with GL2 brackets covers a 25–75 mm cavity/offset from the background, so it suits walls that are badly out of true, need services in the cavity, or need a straighter finish. The depth here is cavity plus board; add the skim (about 2–3 mm) if the lining is plastered.
Common mistake
Setting out door linings and skirtings from the dab depth when the wall is far out of plumb, so the true lining depth in places is much more than the nominal.
Limits
Nominal figures. The actual cavity follows the worst point of the background. Thermal laminates (insulated board) are thicker; use their full thickness for t.
Sources
- British Gypsum, DriLyner Dab installation guide (Gyproc DriWall Adhesive dabs 50–75 mm wide × 250 mm long, 10–25 mm thick when compressed)
- British Gypsum, DriLyner Dab specification BASIC-D (12.5 mm WallBoard Ten on DriWall Adhesive dabs, 10 mm nominal cavity)
- British Gypsum, GypLyner Single GL-S-GL2-1L-WB12 (cavity/offset 25–75 mm; GL1 at 600 mm centres; GL2 brackets at 800 mm centres; GL8 track fixed at 600 mm centres)
Results are calculations from the published methods and manufacturer figures shown, and depend on the data you enter. Always follow the manufacturers’ system and product data, BS 8212, BS EN 13914 and Building Regulations. Coverage rates vary by product, background and thickness. Check prices, VAT and CIS rules with your own records and HMRC.