Start by drawing a square on the wall; size will depend on the size of damage to the gyprock. Just make sure it covers the damage, but don't go
smaller than about four inches, this gives you a more comfortable space to work with
Next cut out the drawn square on the gyprock. Use either an gyprock knife or gyprock saw (saw can be purchased at a dollar store)
Next take a gyprock knife with a sharp blade and cut all around the hole, holding the knife at a 45 degree angle, trim away all the rough edges
Next make a square out of a piece of gyprock to fit the hole. Also trim all the edges with a sharp gyprock knife
Next prepare three strips of 1/4 or 3/8 inch plywood. For this particular hole I cut them two inches wide and two inches longer than the hole. Locate
the center and screw in a gyprock screw, this will help you center the plywood right to left and make sure half the wood will go behind the hole and
half will be into the hole. The screw will be used to hold the wood in place while you are drilling the pilot hole for the screws. Just screw in the depth
of the plywood, we will be removing them later. These wood strips will be slipped into the hole one at a time and be positioned behind the gyprock to
give support to the patch, and will provide a surface to screw the patch to
Next while holding the top plywood in place; drill a 3/32 inch pilot hole for the gyprock screw (this makes the screws easy to start into the plywood,
without applying a great deal of pressure). While holding the plywood in place, screw the gyprock screw into place, and tighten so the head is just
below the gyprock. Repeat the same process for the remaining pieces of plywood. Use the center screw to hold the plywood in place. When all
pieces of plywood are screwed into place; remove the holding screws
This picture shows the last piece of plywood in place. This is how to hold the plywood in place while drilling pilot holes and applying the
screws.
This picture shows all the gyprock screws in place, remember the screws have to be placed in a position to hit the plywood below, but not so close
to the edge as to crush the gyprock, and slightly below the surface, when tightened
Next insert the patch, drill pilot holes and place the gyprock screws in place. Tighten the screws, so the heads are slightly below the surface. For
this patch, four screws will do, a larger hole would require more screws
Next cut and place fiber-glass gyprock mesh tape to cover the hole, extend past the hole one to two inches
This picture shows the fiber glass tape in place. The tape is slightly sticky and will stay in place until you can apply gyprock cement. The tape will
not stick to the wall for very long, so do not just stick on the wall and leave until the next day
Next apply a thin coat of gyprock cement over the area. Just a quick coat is all we want at this point, as this will cement the tape to the wall.
Leave it for a day to dry thoroughly
I find a four inch trowel is comfortable to use. Some refer to the trowel as a gyprock taping knife, but I find it confusing, so I will use the term
gyprock trowel so as not to confuse it with the gyprock cutting knife.
Next apply more coats of gyprock cement to cover the surface of the hole. You should apply enough to allow for sanding yet not to expose the fiber
glass mesh tape. Apply two or three light coats. Apply the gyprock cement four to six inches pass the patch as this will make it less noticeable, when finished. Remember to run the trowel over each layer, when it is dry, to knock off any burrs and high spots, before applying additional coats, this leads to a professional looking job. Place any lighting to the side and this will show any imperfections on the wall.
Gypsum dust is a nuisance and not hazardous, so you can use a common disposable dust mask when sanding.
Totally dry it is now sanded. It was sanded with a medium grit sandpaper and was done with very little pressure. It was finished up in a light circular
motion. If you wish you can start with a sandpaper with120 grit and finish with a 150 grit sandpaper. An alternative to sanding is to use a polyurethane sponge, which provides a dust free method. The sanding will texture the gyprock cement to match the existing gyprock wall. It is ready to prime the area with an gyprock undercoat primer paint (gyprock primer is absolutely necessary or the patch will be smoother then the rest of the wall and have a shine). It is now ready for painting.
This is what it looks like, inside the wall; you can see how the screws have something to hold onto.
Patching Small Holes In Gyprock
If you need to patch small holes like nail and screw holes you only need to make sure there is no lumps along the edge of the holes. Carefully cut away any protrusion or tap in the area around the hole to create a small indent. You can always fill a hole, but lumps are much harder to deal with.
Apply a small amount of gyprock cement and scape away any excess. Let dry for a day, then lightly sand smooth and you are ready for painting. Even with small holes, the cement in the hole may shrink while drying and may require a couple of coats of gyprock cement. If you have a very tiny nail hole to fill, apply a little guprock cement or amazing enough, apply a little toothpaste with your finger, and it will do the job.
Patching Medium Size Holes
To patch a medium size hole, just cut away any lumps or bumps with a sparp knife. Cover hole in a criss-cross fashion with fibre-glass tape, extending a couple of inches past the hole. Apply a first coat of gyprock cement and let dry. When dry run your trowel across the patch and knock off any bumps. Apply another coat and let dry. Continue this process untill you have covered the hole and you have a flat surface. Lightly sand when dry and you are ready to paint.
Gypsum Drywall
Gypsum is a mineral which contains 21 percent water in a crystallized form. About 50 percent of gypsum is water. This ability to hold water makes it
a very good fire resistant material. When gypsum is subject to extreme heat, water in the gypsum is converted into steam, retarding any
flames.
Gypsum wallboard is also great at deadening sound and the board is easy to repair. Gypsum wallboard can be painted, textured and
wallpapered.
An 8 ft. sheet of gypsum wallboard weighs about 54 pounds. The sheets are shipped together in two's, but can be easily separated by removing the
strip of paper which holds them together.
Gypsum drywall sheets come in lengths of 8, 9, 10, 12, 14 and 16 ft. They come in 1/4, 3/8, 1/2, and 5/8 inch thicknesses.
Drywall was developed in the late 1930's by United States Gypsum Company.
Before drywall, plaster was the popular choice.
Preparing Surfaces
Because the drywall is only 1/2 inch thick, it will contour to the surface. If the wall studs are not level, this will show in the finished wall, therefore it
is very important to carefully prepare your walls before dry walling. Use a string to check your walls for bows, etc. Do a measurement of your wall
stud placements and record this on paper for future reference to find the studs. If possible mark each studs position on the floor and ceiling, allowing for the thickness of the wallboard.
Cutting Out Electrical Box Placement
Coat the outer lip of the electrical box with soft chalk or lipstick. Next slide the drywall into place at the correct height and press it against the
electric box. Lightly tap on the wallboard with the end of the hammer handle. This will leave an accurate impression of the electrical box. Cut outside
the line to create a bit of clearance for easy installation.
Installing Drywall
Cover the largest areas first. You may be able to use the smaller pieces that have been cut off. An added benefit is if you make a mistake in your
measurement, you will still be able to use this sheet somewhere else.
Using Joint Compound
Before using joint compound from a bucket, mix it, blending it well. A well blended compound goes on smoothly. Don't overdue the mixing, as this can
trap air in the compound that will go onto the wall as bubbles. When the bubbles pop, they will show up as small holes.
Sanding Drywall
Sand off burrs, ridges and high spots with 120 grit sandpaper. Finish sanding with a 150 grit sandpaper.
When cleaning up don't wash a lot of gyprock cement down the drain
as this can clog up your drain pipes. Rather, first wipe down the gyprock tools
with paper towel and then finish up under the tap. Dry the tools to prevent
any rust from forming.
Clean up any spilled cement while wet. Scoop up what you can
and finish with a damp rag.
How To Cut Gyprock
To cut gyprock, you will need a gyprock knife. Use a sharp blade as dull blades will just tear the paper and will not cut properly. Do your
measurements and pencil a line where you will cut. Lay the gyprock face up on a flat surface and lay a two foot square against the line, kneel on the small end of the square to keep it from moving while you are cutting. Draw the knife along the square, towards you and try to cut about half way through the gyprock; go over the cut a couple of times if necessary. Next bend one section of the gyprock to be cut, up at ninety degrees or a right angle. While holding the upped portion, run the gyprock knife towards yourself, along the line to be cut. Other cuts can be made with a
handsaw with fine teeth.
If you are cutting out material for a light or electrical outlet use a gyprock saw ( tapered blade saw about six inches long with a handle). To start
the cut, place the pointed end of the saw at one of the corners and gently rock the saw back and forth while applying some pressure. Next just saw
along the line until you reach the end of the cut. finish with the other cuts.
Gyprock Dust Clean-up
Gyprock dust creates a real mess. if you step on it, it tracks all over the place. The dust is so fine it floats all over the room. The best way to deal
with it is to trap as much as possible as you are sanding. Place an old bed sheet on the floor below the area you are sanding, then gently sand.
Carefully wrap up the bed sheet and take it out side and give it a good shake. The little bit left around the room can be wiped up with a damp rag.
Finish up with a vacuuming. A regular vacuum will tolerate a bit of gyprock dust, a large amount of gyprock duct will destroy your household vacuum
cleaner. Empty the bag when you finish, even if is a new one. The dust plugs up the bag and prevents air from cooling the motor, which will cause
the motor to overheat. A wet dry vacuum is best to clean up gyprock dust. There is available attachments for a vacuum cleaner which passes the
dust through water before it enters the vacuum cleaner.
Popped Nails or Screws
Popped nails/screws occur anytime there is a space between the stud in the wall and the drywall. This is usually caused because the studs were not
dried properly and contained excess moisture when it was installed. As the studs dried, a space became between the stud and wallboard appeared.
To repair this problem drive the popped nail/screw below the level of the wallboard. Add a nail/screw above and below the popped nail/screw. Finish
up with mudding, sanding and painting.
Water Damaged Gyprock
Extreme water damaged gyprock cannot be repaired because the outside paper covering looses it bond with the interior material which has swelled and crumbled. Any strength of the gyprock is gone, The only solution is to remove the water damaged gyprock and replace with new gyprock.
Nailing Framing Strips
When using powder-actuated nailers, to nail framing strips onto a block (cinder-block), aim for the center of the block. Cinder-blocks have a web in
the center and ends, the rest is hollow.
If you are using masonry nails, drill pilot holes and drive the nails into the mortar joints.
Types of Gyprock
Standard, Flexible, fire-resistant, moisture resistant, abuse resistant, foil-backed, decorative, blue board, high density, cellulose-fiber sound proofing
and mold resistant.
Gypsum wallboard Strength
Gypsum wallboard has a grain that runs parallel to the length, giving panels more strength along the length, rather than across the width.
