Renovation 4th Edition

by Michael Litchfield

thin each coat with 10% mineral spirits. Oil-

  based polyurethanes dry slowly, so apply only

  one coat per day, unless the manufacturer

  recommends otherwise. Here again, sanding

  between coats is not imperative unless you

  wait a week between coats—or you need to

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  sand down imperfections. Before waxing an

  look you like; typically, two or three coats do the

  oil-based poly, be sure to wait a week after the

  trick. Oil finishes offer the least protection but

  last coat dries.

  are easiest to reapply.

  shellac doesn’t have the water resistance of poly-

  urethane, but it dries quickly, has a wonderful

  Painting the Exterior

  old-fashioned sheen, and adheres well to earlier

  Exterior paint jobs can last 10 years or more if

  shellac coats, so it can be touched up repeatedly.

  you’re fastidious about prep work and attentive

  If wood is new or recently stripped, apply a sealer to water-related building details. Key factors

  coat of thinned-down shellac. If you’ll be staining include proper flashing of windows, doors, and

  the wood, first brush on a sealer of 1 part shellac

  roof junctures; maintaining gutter systems;

  to 4 parts denatured alcohol, allowing it to dry.

  caulking gaps in exterior siding; and adequately

  Otherwise, brush or wipe on a coat of 1 part shel-

  venting excess moisture from interior spaces.

  lac to 2 parts denatured alcohol, wiping off the

  excess and allowing the coat to dry for two hours

  before sanding lightly with 320-grit sandpaper.

  Thereafter, apply two or three coats, thinned with

  10% denatured alcohol. If the surface is smooth,

  ladder saFeTy

  there’s no need to sand between coats. Wait one

  day between coats and three days before waxing.

  if you’re painting a whole house, the job will go much faster if you rent scaffolding.

  Because shellac dries so quickly, don’t attempt to

  however, if you decide to use an extension ladder or two, follow these safety rules:

  rebrush it.

   don’t place ladders near incoming electric service lines. When the air is moist,

  Oil finishes include boiled linseed oil, tung oil,

  electricity can arc to nearby objects or people, so keep your distance.

  and the so-called Danish oils like Watco®. Using

   Securely position the ladder. never ascend a ladder that lists to one side. On

  a nylon pad or a rag, rub a generous amount

  uneven ground, use a ladder with adjustable leveling feet, as shown on p. 44.

  of oil onto the wood. Let that soak in for 10 to

   Place the bottom of the ladder out from a building no more than one-quarter the

  15 minutes before rubbing off the excess with a

  ladder’s height.

  clean, dry cloth. With each coat, the wood will

   Wear hard-soled shoes so your feet won’t tire quickly on the ladder rungs.

  darken slightly. Allow each coat to dry for

  24 hours, then reapply the oil until you get the

  P R O T I P

  shellac mixed from dry flakes

  is a terrific finish with better

  water resistance and clarity than

  premixed shellac. also, it’s a

  good idea to check the label for

  an expiration date. old shellac in

  the can won’t dry properly.

  Sheet peeling is caused by excessive moisture migrating through a wall—in this case, an unvented

  bathroom wall.

  Painting

  529

  WhY Paint Fails

  Wrinkling is caused by applying paint too thickly,

  painting an exterior that is too cold, failing to

  Before you sand or scrape anything, figure out

  thin paint sufficiently, applying paint before ear-

  why the paint is failing . . . and where.

  lier coats are dry, or letting the paint get rained

  blistering is usually caused by painting over

  on before it cured adequately. Use a power sander

  damp wood or an earlier coat of paint that isn’t

  to even out the surface before repainting.

  dry. Blisters often contain water vapor, although

  alligatoring, or cross-grain cracking, is caused

  “temperature blisters” are largely hot air, caused

  by too many layers of paint, usually old, oil-based

  by painting a surface that was too hot. Scrape

  paint. The thicker the paint, the less it can flex as

  and sand blisters, allow the wood siding to dry

  siding expands and contracts. So the paint

  thoroughly, and spot prime.

  cracks—sometimes all the way down to bare

  Peeling off in sheets is blistering on a grand

  wood. Alligatoring may also be caused by paint-

  scale—sometimes an entire wall. This is most

  ing over an undercoat that didn’t dry completely.

  common on older homes lacking vapor or air

  In either case, it’s big trouble because you’ll need

  barriers and occurs especially on siding outside

  to strip the paint down to bare wood and seal it

  bathrooms or kitchens, when excessive moisture

  with a primer-sealer before repainting. It may be

  migrates through the wall. If your old house has

  easier to replace the siding.

  been retrofitted with insulation and a vapor bar-

  Chalking is a normal occurrence and isn’t a

  rier, peeling may indicate moisture trapped

  problem unless it’s excessive, usually the result of

  inside the walls and, possibly, rotted framing. At

  cheap paint. Because new paint won’t adhere

  the very least, add ventilator fans to exhaust

  well to a powdery residue, you must scrub and

  water vapor. And on outside walls, drive thin

  rinse the old surface and allow it to dry before

  plastic wedges behind the lap siding to help

  repainting.

  moisture escape.

  rusty nail stains are common where siding

  intercoat peeling, a new coat of paint separat-

  nails are not galvanized. The fastest fix is

  ing from the old, is a classic case of poor prep

  sanding each stain lightly and priming with a

  work. Typically, chalky old paint was not

  rust-inhibiting primer like Kilz® stain blocker.

  scrubbed or sanded and thus new paint could not For a longer-lasting repair, sand until you expose

  adhere. Or, less often, the painter waited too long each nail head, use a nail set to sink each one

  P R O T I P

  between the prime and finish coats. Scrape failed 1⁄8 in. below the surface, prime with stain blocker,

  paint, sand, and wash the surface well, letting it

  and fill with wood filler. Then sand and spot-

  although white pigmented

  dry before repainting.

  shellacs such as b-i-n® are

  prime before painting.

  terrific for blocking stains

  on interior surfaces, they’re

  not advisable for priming

  exteriors. hot sun softens

  and degrades shellac.

  Alligatoring, or cross-grain cracking, is caused by too many layers of old, inflexible paint.

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  Where a random-orbit sander won’t fit, use a
palm sander, as shown, with

  60-grit or 80-grit sandpaper. A palm sander is also handy for scuff-sanding

  old paint in good condition so new paint will adhere better.

  Hand-scrape nooks and crannies that power tools can’t

  reach or could damage. Here, heat guns and chemical

  scrapers also make sense.

  To maximize adhesion, spot-prime

  seams and gaps before caulking them

  with an exterior-grade, paintable

  acrylic or multipolymer caulk. Paint

  won’t stick to pure silicone caulk.

  Tannin bleed-through, a widespread brown

  four years. If that sounds like too much mainte-

  staining, occurs when waterborne resins in

  nance, prime the siding with an oil-based primer,

  woods, such as cedar and redwood, bleed

  and switch to paint.

  through porous latex primers. Scrub the surface

  mold and moss are common in humid climates,

  well, and prime it with one or two coats of an oil-

  on north-facing and foliage-shaded walls, and

  based (alkyd) primer such as Kilz or Benjamin

  where lawn sprinklers hit the house. Siding that’s

  Moore Fresh Start®. Paint what you like—latex

  constantly damp can lead to structural rot. For

  or oil based—over that. At this writing, stain-

  starters, cut back foliage and adjust the sprin-

  blocking acrylic latex primers show promise but

  klers. Scrub moss off by hand, using a wire

  don’t yet have the track record of oil-based stain-

  brush. Remove mold by applying a cleaner/

  blocking primers. Get a second opinion from an

  mildewcide such as Zinsser® Jomax® before

  up-to-date paint supplier.

  scrubbing or power washing the surface (but see

  graying wood is a natural response to sunlight

  the cautions later in this section). After the exte-

  when siding is left unfinished or has been sealed

  rior has dried for about a week, prime as needed,

  with a clear finish that degrades. Never leave

  and repaint with a paint containing a mildewcide.

  wood siding exposed to the elements—both

  because bare wood quickly degrades and because

  PreParing the exterior

  paint or clear finishes don’t adhere well to

  Houses built before 1978 may contain lead paint,

  degraded wood. Sand and wash the surface, and

  so before starting prep work, be sure to review

  reapply a clear finish with a UV-blocking agent.

  Clear finishes need to be reapplied every two to

  Painting

  531

  A mechanical scraper with a vacuum

  using a garden pump sprayer. A dilute solution of

  attachment is the tool of choice

  TSP is often recommended, but urban houses

  when you’ve got to strip exterior

  may need a cleaning agent with a degreaser that

  paint. But set the nail heads first, or

  will cut soot, automobile exhaust, and the like. As

  you’ll chew up expensive scraper

  noted earlier, if there’s mold present, use a clean-

  blades. Eye protection is a must.

  er with a mildewcide. Once the cleaner has had

  time to work, rinse it off with a garden hose and

  allow it to dry thoroughly for a week or so before

  painting. That’s a minimal wash.

  To thoroughly wash and rinse an exterior, rent

  a pressure washer, which has a small boiler and a

  high-pressure electric pump. The rental company

  will recommend a detergent suitable for the unit

  and explain how to use it safely. For most clean-

  ing jobs, 1,800 psi to 2,500 psi is specified—for

  softwoods such as cedar or redwood, use 1,000 psi

  to 1,500 psi. Tip sizes range from 0º (concentrat-

  ed pressure that can easily damage siding) to 40º

  (a wider fan of water favored for light cleaning).

  In general, start with a low-pressure setting until

  you are familiar with the machine, and keep the

  spray wand moving. Note: Always spray down-

  ward if you’re cleaning lapped siding. Otherwise,

  you’ll force water underneath.

  scraping, sanding, spot-priming, caulking.

  Once the siding has dried, hand-scrape the loose

  this chapter’s earlier sections on equipment and

  paint. For this, use a large scraper with a 3-in.-

  lead-paint safety—and test for lead (see p. 515).

  wide blade, preferably one with a forward grip

  Even though you’re working outside, wear a

  over the blade. Be sure to scrape the lower edges

  respirator when sanding or scraping paint and

  of the clapboards and beneath the windowsills.

  when working with solvents or paints of any

  For hard-to-reach areas when siding abuts trim

  kind. Likewise, when applying cleaning solutions or where trim is curved or intricate, use a hand

  (which can be caustic), wear rubber gloves and

  scraper with interchangeable blades. If paint

  eye protection.

  doesn’t come off easily, that’s a good sign—it’s

  Prep work is prodigiously messy, so spread

  well adhered. However, if isolated areas of paint

  drop cloths out 8 ft. from your house to protect

  are too thick or obscure ornamental details, use

  your lawn and shrubs. Otherwise, you’ll be pick-

  a chemical stripper or a heat gun to remove

  ing paint scraps out of your grass for years or—

  more paint.

  even worse—exposing kids and pets to lead-based

  After scraping loose paint, use 80-grit sand-

  paint. If it’s hot and sunny, don’t cover your

  paper to feather out the edges of the remaining

  plants with plastic drop cloths; the plants will

  paint, smooth uneven surfaces, and scuff up sur-

  cook. Instead, use fabric drop cloths, which

  faces so new paint will adhere well. For this

  shade plants, won’t tear, and are far less slippery

  work, an electric palm sander or random-orbital

  to walk on. But if tests indicate lead paint, cap-

  sander is a good tool, powerful yet light enough

  ture the debris in heavy 6-mil plastic tarps,

  to use all day. If you’re prepping painted stucco,

  which you can roll up and discard at the end

  brick, or concrete, instead use a wire brush.

  of each day.

  When you’re done, brush off the dust with a

  hand broom.

  Washing surfaces. Before installing new wood

  If the paint is largely intact, you may not

  siding, apply primer-sealer to the front and back

  need to prime it, but you should spot-prime all

  faces and to all edges. When that coat is dry,

  areas you’ve scraped down to bare wood, plus

  scuff-sand it with 100-grit sandpaper, and dust it

  exposed nail heads and cracks, gaps, and holes

  off with a whisk broom. Then install the siding

  you intend to fill or caulk. Spot-priming blocks

  before applying the topcoats.

  nail stains, seals wood from moisture, and pro-

  However, if the siding is already painted—

  vides a better surface for filler or caulk to adhere

  even if the
paint is in good shape—wash it first.

  to. Use either an exterior-grade polyurethane, a

  Start by applying a house-cleaning solution,

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  paintable acrylic, or a multipolymer caulk; don’t

  reach, use hand scrapers, a chemical stripper, or

  use silicone caulk because paint won’t stick to it.

  small mechanical scrapers like the Metabo®

  This is also a good time to set and fill nail

  Lf724S. When you’ve finished stripping, use a

  heads. Because wood filler shrinks as it dries,

  palm sander or a random-orbit sander with

  slightly overfill the holes. When the filler is dry,

  50-grit to 80-grit sandpaper to smooth out the

  sand it flush.

  rough spots before washing, caulking, dusting,

  Where wood is badly deteriorated, you should and priming.

  replace it. If the trim has only localized rot and

  Chemical strippers are most appropriate where

  would be difficult to replace, scrape the loose

  trim is intricate or where you want to remove

  matter away and impregnate the remaining area

  lead paint without dispersing particles into the

  with an epoxy filler, such as the one shown in the air and soil. Strippers vary in strength, environ-

  photos on p. 163.

  mental impact, working time (4 to 48 hours), and

  method of application. See the sidebar on p. 526

  stripping exterior paint. Stripping exterior

  for a list of solvent-free strippers. Typically,

  paint is a nasty job. Fortunately, only a few paint

  chemicals are brushed thick—roughly 1⁄8 in.—

  conditions require stripping. One of those condi-

  and allowed to work.

  tions is alligatoring, in which many layers of old,

  Given enough time, chemical strippers should

  cracked, oil-based paint resemble the skin of an

  remove all paint layers in one application,

  alligator (see the photo on p. 530). In that case,

  although solvent-free strippers may take repeated

  before stripping to bare wood, get a bid to

  applications. Methods of application vary widely,

  replace the siding. Labor costs should be less, to

  so follow the instructions on the label carefully.

  say nothing of the cost, mess, and health con-

  One example: To keep its stripper from drying

  cerns of stripping lead-based paint. But if you

  out while working, Dumond Chemicals’s Peel

  decide to strip, wear a respirator, eye protection,

  Away® system comes with plasticized paper that’s