Notes on interior painting and wallpaper removal

Last modified: 2023-08-03 12:00

Wallpaper removal

• If wallpaper extends behind a countertop, vanity, mirror, or other obstacle that you have no intention of removing, run a utility knife along the edge to cut the paper at that point.
• Get a sheet started by lifting a corner with a utility knife.  Or trying to.
• Wallpaper comes off in one of three ways, depending on whether the installer was the spawn of Satan or was merely a deeply disturbed individual:
  1. Peels off in one piece, causing no damage to the wall.  Yay.
  2. Peels off in one piece, but rips away a layer of paint at the edges where it was specially glued down.
  3. Will NOT peel off; is glued to the sheetrock with total commitment.  This wallpaper must be painfully removed with chemicals or steam, and the drywall paper will get ripped off in places no matter how careful you are.  Chemicals and steam are both bad options; neither one works reliably and either one can lead to additional damage.  I had better luck with chemicals because the steam was always either too little (dried out too fast) or too much (got into the drywall paper).
• If wallpaper extended past a joint that was caulked over, you may need to scrape or grind away the caulk to get rid of the last of the visible wallpaper.  For hard caulk that is adhered to the drywall (adhesive caulk?), the collateral damage may not be worth it.
• Residual glue is most efficiently removed through dry hand sanding with 120 grit.  It can also be removed with chemicals and a lot of scrubbing, but the underlying paint or primer is impacted either way.
• Prime the entire surface before painting over.

Prepping

• Plan at least 2 hours of prep time for each 1 hour of painting (does not include wallpaper removal).
• If you intend to paint a kitchen while it is still in daily use, figure the cost of marriage counseling and/or divorce into the project.
• If there is an obstacle (shelf, medicine cabinet, window treatment, big-screen TV) that you are comfortable removing from the wall, then remove it.
• Use the right filler in the right place:
  • Cracks get caulk:  all-weather windows & doors caulk, mildew-resistant kitchen & bath caulk, or a paintable silicone-blend caulk, as appropriate.  Plain old latex caulk is OK in most situations, but it does shrink when it dries.
    • If you are caulking along a surface that should not get caulk smeared on it, use masking tape.
  • Shallow imperfections, such as a torn coat of paint or torn drywall paper, get drywall mud.
    • Ripped drywall paper must be primed before mudding to prevent it from absorbing water and wrinkling.
    • If it does get wrinkled, cut away the wrinkled layer of paper with a utility knife and seal it properly the second time.
    • Plan C is to use spackle instead of mud and smooth it out as best can.  Spackle is less likely to wrinkle the paper, but it's not the best for making a thin, smooth layer.
  • Holes in the ceiling and in the tops of window frames get light spackle.  Light spackle is mostly air, but regular spackle is heavy and wants to fall out.
  • Holes in walls get regular spackle.
• Dust from sanding goes everywhere.  Allow ample time for clean-up.
• Use the right masking tape in the right place:
  • Dirty, old, porous, and/or non-delicate surfaces get the plain old masking tape.  The "delicate" tape doesn't adhere as well to bad surfaces.
  • Recently painted surfaces and dainty wallpaper borders get the more expensive "delicate" blue tape.
  • The top of the wall base gets the most expensive blue tape with the super-duper paint-blocker technology.  Gravity is working against you; the seal must be perfect.

Painting

• At a minimum, unpainted surfaces, bad surfaces (e.g., contaminated with wallpaper adhesive), drywall mud, spackle, and caulk that you intend to paint must be primed.  Priming the entire surface that is to be painted is often essential and is seldom a mistake.
• With new premium paints that are self-priming, the first coat goes on like tinted primer, with not much flow.  The second coat gives a proper finish.  I would not use a separate primer unless the surface called for special treatment or needed an oil-based primer.
• Any given paint store has a bewildering variety of products.  Besides coming in at least four different levels of sheen (flat, eggshell or satin, semi-gloss, and gloss), in exterior and interior varieties, and at several different cost vs. performance levels, paint is furthermore available in a large number of special-purpose formulations to deal with particular surfaces or conditions.  The variety of primers has similarly multiplied beyond simply oil-based or water-based to include special formulations for particular challenges (such as sealing over wallpaper adhesive).  Switching from one brand to another or one product to another, you'll find differences in how it goes on, how fast it dries, how well it covers, and how long it lasts.  Apart from reading the labels and avoiding the cheap-out varieties, there's no clear answer to picking a winner.  You can't even stick with a winner once you find it:  come back two years later and they will have changed the base.
• Choosing colors:
  • The easiest mistake is choosing a color that is too dark and/or saturated.  If you're aiming for just a hint of color, you may need to ask the paint store to mix a custom color that is lighter than the lightest one on the strip.
  • It is a myth that a paint shop can match any color if you bring it to them.  Sometimes you get the same washed-out garbage color everywhere you go.
  • With grays you trade the problem of matching colors for the problem of matching undertones.  Warm lighting turns gray to purple.
  • Paint samples are somewhat helpful, but they don't cover well, the sheen is different, and they add to the problems that you are painting over.  You never really know until you put up the real thing.
  • IMHO, socket and switch covers look better if they are painted to match the trim rather than the wall.
  • IMHO, bright white ceiling paint gives a clean and modern look to a room.  Unfortunately, if you want to change one ceiling, you have to change them all.
• Old leftover paint must be used with caution.  Old paint often gets contaminated (those cans rust for some reason), and even in the best of circumstances won't necessarily match a new batch that is mixed to the same color.
• One coat is sometimes good enough if you're not covering a conflicting color or sheen, but it is never great.  Two coats should do it unless there's a problem.
• Getting edges and corners to match the rest of the wall is difficult.
  • Whenever practical, do the edges and corners with the same tool as the rest, or as similar as possible.  Many mini-rollers can be mashed into corners successfully.
  • For brushed edges and corners to match a rolled wall, you have to lay it on thick.
  • Edging pads only smear on a thin coat of paint, and loading them up only makes a huge mess.  When there is no alternative (i.e., you're painting with a pole), use as directed ("float in paint" means "float in paint," very carefully) but plan on doing the edges two or three times and living with the ridge that this creates.
  • When all else fails, do another coat.
• Paint gets darker as it dries.
• Although latex paint dries in hours, the topcoat remains soft and easily damaged for days to weeks.
• If dried latex paint is subjected to a lot of moisture, surfactant may leach out of it and form yellowish spots or streaks.  Ironically, I have found that these marks are easily wiped off of flat paint with a damp sponge, while they permanently dull the sheen of semi-gloss paint.

Unpainting (when there is paint where it should not be)

Time is of the essence.  The longer it dries, the harder it is to remove.

• Wipe it off immediately.  (Water-based wipes up easily; oil-based tends to smear.)
• Clean it off with 70% isopropyl alcohol.  (Alcohol dissolves all latex paint, but uncured paint dissolves a lot faster.)
• Scrape it off.
• Sand it off.
• Paint over it.

Masking tape removal

Sometimes, if the paint is dry but not yet cured, you can remove masking tape without tearing the topcoat.  If it works, then great.  Often, however, you can't.  Primer seems to make it worse.

There are two methods of removing masking tape without risk of tearing the paint coating:

1. The wet method:  Remove the masking tape while the paint is still wet but no longer flowing.  Then retape everything if you need to do another coat.
2. The dry method:  Let the paint dry, then run a utility knife along the edge before pulling off the tape.

When dealing with wallpaper borders, even the "delicate" blue tape must be removed cautiously to avoid ripping the wallpaper.

Incompatibilities

The old line about can't put water-based paint over oil-based paint is generally hogwash, but anything that isn't completely cured when you topcoat it can cause problems.  I put this primer (which worked fine everywhere else) over this paintable caulk (which I'd never used before) and it utterly failed to adhere.  Days later, the dried paint was sticky and came off on my finger, and the caulk seemed putty-like.

Pure silicone caulk is incompatible with water-based paint or primer.  Preferably it would never end up somewhere that needs to be painted, but if it already has, you can roughen the surface, smear it with oil-based primer, and then topcoat with anything.

Mistakes

• Do not assume that you can buy quarts.  Paint shops' color recipes are for gallons and don't always divide evenly by four.  They are also less likely to have the correct base in a quart size.
• Do not drip paint onto carpet.  Especially do not drip oil-based primer onto carpet.
• Do not apply paint samples over wallpaper residue.  Clean and prime the walls first.
• Do not apply thick coats of paint samples.  It doesn't help.
• Do not use a belt sander on the wall.  If the wall is not perfectly flat it will instantly cut into the drywall.
• Do not use a cheap fuzzy paint roller with semi-gloss paint.  It doesn't apply smoothly.  A good quality roller is OK; foam is OK.
• Do not touch up semi-gloss paint that has begun to dry.  It ruins the sheen.
• Do not touch up with the wrong sheen.
• Do not glop paint into the edges when painting the ceiling.  It could run down the wall.
• Do not reuse a paint tray without cleaning it first.  Wet paint softens the dry paint, and the dry paint breaks up into clumps.
• Do not allow a high-end paint store to substitute the midtone base because they are out of white.  It won't cover as well, and you end up paying a high-end price for the equivalent of a low-end paint.
• Do not confuse light colored paint with white paint.  They both look white until they are dry.
• Do not ruin a good paint job by smearing caulk on it.
• Do not underestimate the ability of painting projects to escalate.  Once you paint one thing, it makes everything you didn't paint look bad.

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