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How to Repair Drywall

In every type of building, be it an office, hospital, church, etc., walls need to be painted. Today, the majority of walls in these buildings are drywall. If you want to paint drywall though, the drywall must be prepared first. As with any painting project, the preparation is the most important part of the job. Before the drywall is painted, which is the easy part, one must follow a few simple preparation procedures for how to repair drywall.

Let’s assume the drywall in your office need to be painted, which hasn’t been done in 8 years or so. The first step in the preparation process would be to wash the drywall down. Most of the time, all that is needed to do this is a bucket of warm water, which will remove any dirt, dust, or other contamination. If your washroom or breakroom is a little dirtier, simply add a mild household detergent to the warm water. The presence of mold or mildew in those rooms requires adding a tablespoon of ammonia to the hot water. Always remember: walls must be cleaned before they can be painted.

Next comes a little trick, something that even a professional painting contractor might not do – take a piece of 120 grit sandpaper and rub down the drywall. This will remove old roller hairs and other imperfections in the drywall that you don’t want to be seen once the walls have been repainted. If you have enough time, take a damp sponge and wipe down the drywall to remove any sanding residue.

Now comes drywall repair. These repairs often involve stress cracks, small holes, and dents among other things. Minor picture holes can be mended by filling them with spackle (note: if you’re using spackle to repair small holes, plan on 2-3 applications before the patch is flush with the drywall. This is on account of the product shrinking when it dries). Any repairs beyond that will require a drywall patching compound such as Durabond 45 (dries in 45 minutes). If stress cracks are present in your office, as is almost always the case, you will also need a roll of fiberglass tape. This can be found at any local paint or hardware store.

Listed below is a simple procedure for patching stress cracks:

  • Take a scraper and “open up” the crack. Remove any loose drywall/paint then fill with latex caulk.
  • Apply fiberglass tape over the drywall crack. The crack will still be visible, but will be bridged over by the pliable fiberglass tape.
  • Now take some Durabond 45 or similar drywall patching compound and apply it over the fiberglass tape. It will take up to three applications – 4”, 6” and 8” wide – until the tape is fully blended with the drywall. Sand with 120 grit sandpaper in between coats.
  • Since your newly patched drywall will have a smooth finish, prime with a high build primer using a ¾” roller sleeve to create a “stipple”. This will help your repair blend in and not broadcast next to the original drywall roller stipple.

Professional Tip: if the face paper of the drywall is torn off, often caused by vinyl base or wall covering removal, and you see brown paper, it needs to be sealed. A common misconception regarding this issue is that drywall patching compound should be applied to the brown paper. The water in the patching compound wets the paper and causes bubbles in the patch. Consequently, you will need to ‘repair the repair’ – which is not fun and costs you valuable time. A good way to seal any brown paper is by using products like Zinsser’s Gardz or XIM Peel Bond. These clear products seal the drywall so that the patching compound’s moisture won’t react with the paper. After sealing the brown paper, you’re ready to patch the drywall. View a video demonstration of this process as done by a McCahill Painting Specialist:

Most drywall repairs require between 2-4 coats of patching compound before the repair is complete. The drywall will need sanding with 120 grit sandpaper in between coats. Be sure to knock off any nubs or heavier lines before you apply subsequent coats of compound. Remember that, while sanding, the dust will travel far from the sanding area if there are open doors or windows in your office. It is always a good idea to put plastic over your office assets to protect them from retaining dust while sanding walls. A great alternative though is sanding with a drywall vacuum attachment; a sander with a vacuum attached to suck up most of the dust.

At this point, you are almost done with the preparation and ready to paint your drywall. There are three simple procedures left to complete. First, you have to spot prime you drywall patches with a quality drywall primer. It’s best to use a 3” wide Whizz Sleeve (easily found at any local paint/hardware store) to apply the primer. This type of sleeve leaves a roller stipple which blends in better when you paint drywall with a half inch roller sleeve. Do not prime with a brush, as the brush stroke will broadcast through the finish paint. This in turn makes the patch become noticeable.

Next, check around window/door frames. If you see gaps in the connection between your wall and window, take a quality latex caulk and fill them in. To do this, take a caulk gun and run a light bead of caulk down the affected area. Once that is done, wet your finger and slowly run it over the bead of caulk to push it into the surface and blend it.

You’re almost ready to paint the drywall. The last preparation step is to tape off any substrates that you don’t want paint to hit. If you are inexperienced, tape off all baseboards, door frames, window frames, etc. in order to have a good edge throughout the room. Furthermore, make sure to thoroughly cover all furniture and floors with painting tarps or plastic. Lastly, always do one final walkthrough before painting to ensure that your office is protected. It’s better to spend an extra 2 minutes putting up plastic than spending hours removing paint overspray off your equipment.

Now you’re ready to paint! Start with a new ½ inch roller sleeve. Place a piece of masking tape on the roller, then quickly tear it off. You’ll be surprised to see how many roller hairs are removed; hairs that otherwise would be all over the walls.

Good luck!

McCahill Painting is an ISNetworld Member Contractor, underscoring our commitment to safety, training and sound business practices.