Patching Downlight Holes in Plasterboard
Circular pieces of plasterboard are very difficult to cut, so the best plan is to cut the ceiling back to a square opening around the original downlight holes using a keyhole saw. Next, cut a patch of plasterboard to fit snugly in the opening, and use plasterboard repair clips to provide a backing for the new piece. These clips can be secured to the edges of the hole with screws, and then the patch can be attached to them.
Once the patch is secured, snap off the tabs that were holding the clips in position and apply filling compound along the joints then embed jointing tape in it. Once dry, apply a coat of finishing compound, extending it about 100mm past the edges of the repair. Leave it to dry then sand with 180 grit abrasive paper, prime then paint.
Plasterboard repair kits are available from Boral, but if you've got a number of holes to fill, it will probably be more cost-effective to just buy a sheet of plasterboard and a few packs of clips, plus a roll of jointing tape and a bucket of filling and finishing compound.
You can cut openings for recessed lights with a variety of circle-cutters or hole saws.
Circle-cutters can be adjusted from 40mm up to 270mm. Some also come with transparent cowling. For more information, visit OzGear's website at OzGear.com.au
Hole saws, like cutters, fit into your drill chuck. When cutting plasterboard, they're best operated at low speed. A wide range of sizes is available. Bordo manufactures continuous-grit hole saws in the five major downlight sizes: 72, 75, 89, 92 and 95mm.
A flexible dustbowl fits between the drill chuck and the hole saw, to collect the plasterboard dust as it falls - protecting your eyes and lungs (see Photos 1 and 2).
The tungsten carbide grit on these hole saws will cut plasterboard, fibreboard and cement sheeting with equal ease and accuracy.
For further information, visit Bordo's website at bordo.com.au
The dust bowl flexes as you drill upwards. The plasterboard dust falls into the cowling (dust bowl), preventing mess and dust in your eyes.
The collected plasterboard can be disposed of safely in a rubbish container. To clean the cowling, simply wipe it out with a damp rag.
WATER AND DRAINAGE PIPES
Plasterboard saws make quick work of holes needed in interior walls.
Measure and lay out the positions of water and drainage pipes that will need to come through the wall. A T-square (Photo 1) comes in handy for marking pipe positions. Draw the vertical lines first, and then make horizontal lines by setting your pencil at the correct distance on the square and sliding the square along the finished edge.
Instead of using a circle cutter, trace the round hole slightly larger than the diameter of the pipe, and then cut the hole with a plasterboard saw. It's best to angle the saw slightly, so the opening at the back is larger than at the front. This way, the pipe will slip into the opening more easily. If you cut along the outside of the lines, the pipe should fit comfortably.
TIP: Avoid broken edges like the plague! To fix them, you'll have to cut away all loose paper and broken plasterboard, and then fill the gap with setting compound. After this, you'll have to apply tape and several coats of taping compound. Work carefully to avoid this problem.
Mark the position of the drainage pipe using a pencil and T-square, which will slide easily along the top edge of the plasterboard panel.
Punch the plasterboard saw through the plasterboard with the heel of your hand, then saw along the outside of the line.