Lets do an all purpose drywall repair, suited to many applications.
To do this, consider: the size of the replacement and the location on the wall.
This repair is for walls & horizontal surfaces while a
has different requirements.
Tools needed consist of a drywall saw, a handheld rasp, fiberglass mesh or paper tape whichever
you prefer, drywall screws, drywall gun and screwdriver, a small square and pencil, a cats-claw
and/or a nail puller, a simple set of taping knives, bedding compound and tools to finish with, such
as a sandpaper pad with about 120 grit on and sanding sponges for tight areas.
1) Determine the needed cutout size in rectangular/square dimension.
This should extend beyond where any inner damage or weakening
of the gypsum exists - drywall can often tear off from the inside so look
inside the wall with a light. Also notice the correct thickness of drywall
as the repair section thickness be the same. Clear out any loose hanging gypsum
and stay clear of any wiring or plumbing inside the wall.
2) Going by an arbitrary 10" by 12" size, transfer this dimension onto
a spare piece of drywall. Tracing with a pencil, not ink (which bleeds)
the cutout and clean to a straight edge with your drywall rasp as you see fit.
Next, overlay the new cutout section centered onto the portion to be patched, hold
and trace to a matching dimension. Remove and cut the outline marking with a drywall saw
or knife, while, ideally removing any traces of the marking for a barely larger cutout size
than replacement cut, and going only deep enough through to seperate the material from itself.
Electric drywall routers can make short work of the cuts, but be prepared for added dust.
Most have depth gauges, which can prevent the hitting of wiring or other concealed items.
You might need to again run the rasp at the cutout edges but this time on the wall side,
to accommodate a neat fit, but not too tight. With the wall opening sized and ready to
receive the patch cut, you are ready for the next step.
3) Creating support - place metal drywall clips, along each of the
open sides and fasten to the wall with screws (set screwgun to lower force due to the
fact that the hole-punched clips strip out easily, else fasten with a hand screwdriver).
Be cautious not to mash the gypsum into the open section with the inserted screws by placing
at an adequate setback from the edge.
At this point, put the cutout section into the created opening to verify fit before screwing
in place on this replaced piece. Note that coarse screws may be required since many of the
clips are pre-packaged today with fine thread drywall screws.
4) With the cutout installed, cut four strips of fiberglass mesh (or paper tape)
that will extend over the corner seams roughly an inch both ways. (the stickness of the mesh makes
placement easy since this type of tape can be pressed and stuck in place). Set the mesh firmly in place.
5) With properly mixed compound - if mesh is used; knife on the mud while
pressing adequately into the open seam area, observing that the crevice need not be completely
filled. If paper tape is used, mud the joint all the way around first and then follow with tape on
seams with your knife; which should be about a 3" knife at this early stage.
Smooth overtop, taking care not to overwork either style of tape as the paper can crinkle
and slide while the mesh can fray and raise from the surface. Let dry overnight.
6) Once dry, surface sand as needed to taper to greater smoothness and then apply
7) Top coat and sand to desired finish. Don't forget to clean any dust and accumulations
as soon as you can to prevent any further transfer by foot traffic.