Dry Lining
Friday, August 3, 2007 at 12:07AM Dry Lining
Still relatively unfamiliar beyond professional builders in the UK , dry lining is much more widely used in other countries, especially where timber framed houses are much more common.
What is dry lining?
Dry lining is the fixing of plasterboard to a background, commonly masonry, timber or metal. It is quick, relatively clean and immediately functional. This gives dry lining big advantages over sand and cement renders or two coat plaster systems.
How to Dry line
Timber
Known as tacking, fixing of plasterboard to ceiling joists and stud walls is a relatively straightforward process.
- Measure. Plasterboard need only be cut to an accuracy of 5mm. Trying to be too exact will slow the job down, cause frustration and make no difference to the finished job. For walls always leave the boards an inch short of the floor and push them up to the ceiling. Top tip! When making a complicated cut, always take each measurement from the same edge of the board. Preferably, the edge that will butt to the previous board. It may help initially to mark with pencil on the face of the boards where the studs will be so the screws locate.
- Cut. Having marked your cuts with a straightedge and a pencil, score the paper once with a Stanley knife and snap the board. Once folded over, cut through the paper on the other side. Scoring only works with a continuous straight cut. For squares or curves use a plasterboard saw (an old saw will do to start though).
- Fix. While nails are still popular the modern method uses plasterboard screws. An 8x4 sheet should have six screws evenly spaced into each joist. Boards are always fixed running across the ceiling joists. On walls they can go upright or laying on their side but the convention is to have them standing up (in most new houses the ceiling is a shade under 8 feet high). Ceiling joists spaced 400mm apart or less do not need fixings into noggins along the long edges of the boards. Joists spaced up to 600mm apart do need fixings into noggins to stop the boards sagging.
Masonry
‘Dot and Dab’ or ‘sticking’ is harder to master than tacking, but it still relies on good measurement and a systematic approach.
Measuring and cutting are exactly the same as before. The most important thing is to leave the boards one inch too short so they can be lifted up to the ceiling and held in place with squares of plasterboard off cuts while the adhesive sets. Skirting will cover the gap between the board and the floor.
Fix. Plasterboard adhesive is mixed in a big bucket in a similar way to plaster. It is approximately one bucket of water to one bag of adhesive. Water in first, then add the adhesive while mixing with a drill powered whisk. The consistency needs to be thicker than for plaster, but only practice can teach you what is suitable. Adhesive is ‘thrown’ onto the wall using a trowel and hawk. Again, practise is key but the aim is for fist-sized peaks of adhesive that stick to the masonry.
Dabs should be spaced a hand widths apart, four vertical columns per 8x4 sheet. Dabs should be continuous at the top and bottom of each board to avoid drafts, and in the corners of a room.
The board is laid against the wall, lifted to the ceiling with a board lifter and wedged with off cuts of plasterboard. Using an aluminium featheredge, the board is gently pushed against the wall. The adhesive spreads and the board is checked for square in all directions.
For detailed technical information on dry lining see the plasterers bible, the British Gypsum ‘white book’ at www.british-gypsum.bpb.co.uk/
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