Under construction - information may be incomplete, or just plain wrong
General plasterboarding information, tips and tricks
- Typical thicknesses are 9.5mm and 12.5mm. Thicker sizes , eg 15mm or 18mm exist as well as thinner, eg 6mm.
- Sheet sizes are commonly 2.4 x 1.2m (aka 8ft by 4ft, most usual size), and 1.8m x 0.9m (for easier handling, especially on ceilings).
- Plain - paper both sides. Usually beige or grey in colour.
- Vapour barrier or vapour check - usually with a metallised plastic film (which may degrade radio signals such as cordless telephones or Wifi).
- Fire check - usually pink in colour
- Moisture shield - for areas of high humidity, usually green.
- Sound block or acoustic plasterboard - usually blue.
- Various combinations of the above properties, dependant on manufacturer.
- Taper - for filling prior to painting direct.
- Square edge - used when a skim coat of plaster is going to be applied.
Not every permutation of edge, type, size and thickness are available so you should check with your local supplier before committing to a particular design.
For certain applications, you may need to meet certain levels of fire resistance or acoustic performance. For now, this is an area too involved to cover here, so please seek the advice of your local Building Control department at your Borough/District Council if you have any doubts.
There are three basic types of cut most commonly needed:
Straight cut across full board
- Used all the time when boarding large areas
- Very easy and clean to do.
- Place board across a couple of supports (eg sawhorses, workmates or even lumps of timber or bricks if nothing else to hand). Be sure the board is well supported near the new cut and stable.
- Mark the cut line
- Score through the cardboard layer on one side of the board with a sharp stanley type knife. A couple of lighter strokes are better (and safer) than applying serious pressure. Always work the knife away from your body and hands - it's very easy for the knife to slip.
- Position the board so that one of the supports runs parallel and just behind the score line.
- Put the knife away(!)
- Using both hands (better two people, if the cut is long, eg 2.4m board), gently rotate the board edge downwards. The board should snap cleanly along the scored line.
- The cut section of the board will continue to hang on the layer of cardboard on the back. Do not attempt to rip by tearing the cut section off - it will make a mess.
- Retrieve the knife and whilst supporting the cut section at 45-90 degrees, simply cut through the remaining cardboard. The result should be a clean straight edge, mostly square with almost no dust.
- If desired the edge may be cleaned up with sandpaper, a coarse file or a coarse hand stone (this bit makes some mess).
Alternative method requiring less space and handling
- Have the board vertical, leaning against a wall.
- Use a metal straight edge (long level typically), mark two points and align the level holding the bottom of it with your foot, and the top with one hand, then score with the other.
- Snap the board by hitting it in the middle of the back of the cut, and separate.
All in all it takes less space, and less handling of the board. You also are less liekly to damage a board getting in and out of cutting positions.
See section on Holesaw
- Generally you will need some sort of saw. A hacksaw blade in a suitable holder will suffice for small works.
- For extended work or cutting square holes for lightswitches, proper plasterboard saws are available which have pointy ends for piercing the board and coarse teeth.
Removing a rectangular section from a corner or edge can be done with a combination of sawing and scoring for the final cut.
To wood (eg ceilings and wooden studwork)
- The sheets may be screwed (best) or nailed (old fashioned method, not so good as nails can loosen) directly to the studwork or ceiling rafters.
- For nailing, plasterboard nails with a flat head are needed. Other nails will pull through.
- For screwing, purpose made drywall screws exist. These have a continuous thread, bugle head (designed not to tear the paper which weakens the fixing), a very sharp point for self drilling and are not liable to corrode. On the end of a small cordless electric screwdriver, these generally go in single handed, quickly and securely. The heads will become "lost" in the surface of the plasterboard. Purpose made driver bits are available that help to prevent the screw going in too deep.
- Be aware if you are screwing or nailing over an area with low support (eg a hole in the previous plasterboard that you are covering. The screws can crack small sections of your new board especially near the edge.
- Put enough screws or nails in to support the board so it feels firm all over. Every 30cm is a reasonable gauge (you want to avoid any parts of the boards being able to flex significantly if you are going to skim plaster it). Obviously, rafter or studwork puts limits on screw spacings in one direction.
Notes for ceiling work
1.8 x 0.9m x 9mm board is easily handled by two people without additional props. One person should have the screwdriver at the ready with plenty of screws and be in a position to rest the board on their head periodically whilst reaching for the next screw. Once a few well spaced screws are in supporting the whole board, both people can let go and concentrate on getting the rest of the screws in.
Working single handedly is also possible using props. A variety of tools are available or can be made:
- Plasterboard lifters Google search. Expensive and generally used by contractors on large projects, but also hireable.
- Plasterboard prop Google search. Cheaper ready made solution.
- A DIY prop may be made from a long length of wood and a shorter T bar fixed across the top. See here: Dead_man_prop
To brickwork and old plaster
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