Renovation 4th Edition

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Renovation 4th Edition Page 19

by Michael Litchfield


  12–1

  19–5

  17–8

  16–7

  14–10

  23–7

  21–1

  19–3

  17–2

  no. 2

  11–0

  10–0

  9–5

  8–9

  14–6

  13–2

  12–5

  11–4

  18–6 16–10

  15–6

  13–10

  22–6

  19–8

  17–11

  16–1

  no. 3

  9–8

  8–5

  7–8

  6–10

  12–4

  10–8

  9–9

  8–8

  15–0

  13–0

  11–10

  10–7

  17–5

  15–1

  13–9

  12–4

  Spruce- sel. struc.

  11–0

  10–0

  9–5

  8–9

  14–6

  13–2

  12–5

  11–6

  18–6

  16–10 15–10

  14–8

  22–6

  20–6

  19–3

  17–11

  pine-fir no. 1

  10–9

  9–9

  9–2

  8–6

  14–2

  12–10

  12–1

  11–3

  18–0

  16–5

  15–5

  14–1

  21–11 19–11

  18–3

  16–3

  (South) no. 2

  10–5

  9–6

  8–11

  8–3

  13–9

  12–6

  11–9 10–10

  17–6

  15–11

  14–9

  13–3

  21–4

  18–9

  17–2

  15–4

  

  no. 3

  9–3

  8–0

  7–3

  6–6

  11–8

  10–1

  9–3

  8–3

  14–3

  12–4

  11–3

  10–1

  16–6

  14–4

  13–1

  11–8

  Western sel. struc.

  10–9

  9–9

  9–2

  8–6

  14–2

  12–10

  12–1

  11–3

  18–0

  16–5

  15–5

  14–3

  21–11 19–11

  18–6

  16–6

  woods

  no. 1

  10–5

  9–6

  8–11

  8–0

  13–9

  12–4

  11–4

  10–1

  17–5

  15–1

  13–10

  12–4

  20–3

  17–6

  16–0

  14–4

  

  no. 2

  10–1

  9–2

  8–8

  8–0

  13–4

  12–1

  11–4

  10–1

  17–0

  15–1

  13–10

  12–4

  20–3

  17–6

  16–0

  14–4

  no. 3

  8–5

  7–3

  6–8

  5–11

  10–8

  9–3

  8–5

  7–6

  13–0

  11–3

  10–3

  9–2

  15–1

  13–1

  11–11

  10–8

  * Design Criteria: Strength – 30 lb. per sq. ft. live load, plus 10 lb. per sq. ft. dead load. Deflection – Limited in span in inches divided by 360 for live load only.

  This table is used courtesy of Western Wood Products Association (www.wwpa.org) and is excerpted from Western Lumber span tables of Floor and ceiling joists and roof rafters.

  For more information about lumber grades, see pp. 58–59.

  Latex acrylics are a good balance of perfor-

  from product to product. Although some

  mance, price, and workability.

  manufacturers tout spectacular performance

   Advantages: Latex acrylics are water

  specs, check out online contractor chat groups

  based, hence nontoxic, largely odor free, and

  for real-life performance ratings.

  easy to apply (you can shape caulk joints with

  your finger). They clean up with soap and

  water. They adhere well to a range of

  materials, have good UV resistance, and can be

  painted. Durable once cured, they are best

  used in protected areas in temperate climates.

   Disadvantages: Expect significant

  shrinkage (up to 30%) and long curing times.

  Although good as bedding caulk under door or

  window casing, they’re iffy as exterior caulk or

  shower and tub caulk. Properties vary widely

  building materials

  77

  5 Roofs

  A roof is a building’s most important layer of

  defense against water, wind, and sun. Properly

  constructed and maintained, a roof deflects rain

  and snowmelt, and routes them away from other

  house surfaces. Historically, roof materials have

  included straw, clay tile, wood, and slate. Although

  many of these materials are still used, most roofs

  installed today are asphalt-based composites.

  If roofs consisted simply of two sloping planes,

  covering them would be easy. But today’s roofs

  have protruding vent pipes, chimneys, skylights,

  dormers, and the like—all potential water dams

  and channels that need to be flashed to guide

  water around them. Then, as runoff approaches

  the lower reaches of the roof, it must be directed

  away from the building by means of overhangs,

  drip-edges, and—finally—gutters and downspouts.

  This chapter assumes the foundation and

  framing are stable. Because structural shifting or

  settling can cause roofing materials to separate

  and leak, you should fix structural problems

  before repairing or replacing a roof.

  Roof ventilation is another important part of

  house health and comfort. Venting excessively

  moist air can forestall condensation, mold, rot,

  and, in colder climates, ice dams. Heat buildup

  under the roof can also be mitigated by adequate

  ventilation. The topic is so important that it is

  discussed here and in chapters 7 and 14.

  Roof Safety and Equipment

  Among the building trades, roofing is considered

  the most dangerous—not because it’s inherently

  Although these wood shingles seem randomly placed, the installer is taking

  hazardous but because it takes place high

  great pains to offset the shingle joints between courses and maintain a

  above the ground. The steeper the roof pitch

  minimum exposure of 5 in. so the roof will be durable as well as distinctive.

  is, the greater the risk. If heights make you

  uneasy or if you�
�re not particularly agile, hire a

  licensed contractor.

  78

  Reputation, License,

  and insurance

  Before hiring a roofing contractor, call your local

  office of the Better Business Bureau to see if

  complaints have been lodged and check with the

  state licensing board to determine if the con-

  tractor is properly licensed and bonded. Ask to

  see current certificates of liability insurance

  coverage and workers’ compensation. Otherwise,

  even if a contractor misrepresents his creden-

  tials, you could be liable for injuries the con-

  tractor and his crew sustain on your property.

  Commonsense safety

   Stay off the roof unless you have a

  compelling reason to be on it. Besides being

  hazardous to you, walking on a roof can

  damage roofing materials.

  A gauge stop on the base of a pneumatic nailer can be used to set the correct shingle exposure.

   If you must work on a roof, make sure

  When the gauge stop is snug to the butt of a shingle, the next shingle above—placed against the

  there’s a second person within earshot in case

  nose of the tool—will be positioned correctly.

  you fall or need help.

   Don’t venture up when the roof is wet or

  near freezing or extremely warm. When wet,

  most roofing materials are slippery. Cold

  asphalt shingles are brittle; warm asphalt can

  stretch and tear. Always wear shoes with soft,

  Warranty issues

  nonslip soles.

  If you observe product defects such as premature wear or curling, ask the roofing

   Position ladder feet securely away from

  company that installed the shingles to inspect them and advise you on warranty

  the building about one-quarter of the ladder’s

  issues. (Always keep records of installations.) If the roofer is reputable, he probably

  extended length. Never lean sideways from a

  ladder. If you can’t reach something while

  has a longstanding relationship with the manufacturer and can exert more pressure to

  keeping your hips within ladder sides, move

  settle disputes than you could. If the original roofer isn’t cooperative, get a second

  the ladder.

  opinion from a competitor.

  If you buy a good-quality 30-year shingle, however, product defects are rare.

   When installing a roof, use scaffolding

  with a safety rail. The most dangerous part of

  Shingles will often shed water far longer than their stated warranty period. Moreover,

  a roofing job—apart from tearing off shingles

  roofs rarely fail in the field: They fail around the edges, around vents, at chimneys, at

  and underlayment—is applying the first few

  wall-to-roof flashing, and around skylights. Failures are usually caused by something

  courses along the eaves.

  that rusts or works loose, caulking that wears out, or nails that pull out because they

   When walking on a roof, try to “walk on

  were nailed through multiple layers of old shingles—or weren’t nailed to sheathing at

  nails.” In other words, try to walk directly over

  all. Leaks are rarely caused by shingle granules or substrate wearing out.

  the rafters, where the sheathing is nailed. The

  For this reason, I’m somewhat skeptical about so-called “lifetime shingles.” Who’s

  roof will be less springy over rafters, and you’ll

  going to be around to pay out or collect on defective shingles 50 years after they were

  be less likely to break through rotten sheathing.

  installed? Besides, most lifetime warranties cover only the cost of replacing the

   Follow the roofing manufacturer’s instal-

  materials, not labor costs, which are typically 75% to 80% of the job.

  lation instructions, which often provide time-

  and money-saving tips. Moreover, if roofing

  has been correctly installed, manufacturers

  are more likely to honor their warranties.

  Roofs

  79

  equipment

  roof, as shown in “Venting a Roof” on p. 90, can

  prolong shingle life somewhat, but the key to a

  Unless you are installing roofing systems that

  long-lasting roof is the quality of the materials

  need to be “torched” (heat-sealed with a propane

  and attention to details, especially flashing

  torch), you won’t need a lot of specialized equip-

  around chimneys, skylights, and vent pipes.

  ment or tools. Most of the items discussed here

  In the long haul, shingles with a 30-year war-

  are safety related.

  ranty are a smarter buy than 20-year shingles

  Footwear should be sneakers or other soft-soled

  because they last significantly longer, even though

  shoes that grip well on a roof. Old-time roofers

  they cost only a little more. Typically, 75% of a

  prefer boots with thick soles that are less likely to roofing job’s cost is labor.

  be punctured by stray nails, but they are inflexi-

  ble and don’t grip as well.

  When it’s time to teaR off

  scaffolding can make applying the first few

  Short term, you can save money by installing a

  courses along the eaves far safer. After the lower

  new roof over an old one if local codes allow.

  courses are installed, the scaffolding serves mainly However, new roofing applied over old (see p. 97)

  as a staging area for materials and tools.

  rarely lasts as long as roofing installed on a

  stripped and properly prepared substrate.

  roofing jacks enable you to work safely on roofs

  You must tear off existing roofing under these

  with a 6-in-12 pitch or steeper. (Several different

  conditions:

  roof pitches are shown in “Gutter Lip and Roof

  Pitch” on p. 178.) Jacks also are indispensable

  The roof already has two roofing layers. Two

  platforms for storing materials. As you work up a is the limit for most local codes because it’s virtu-

  roof, install additional pairs of jacks whenever

  ally impossible to install a third layer that will lie

  you must stretch to nail the next course. As

  flat. Even if you could, three layers would be a

  shown in the photo on p. 78, many roofers leave

  nightmare to flash and nail correctly. Underlying

  jacks installed until the job is almost completed.

  shingle layers are a springy substrate to nail

  through, and old wood shingles often split and

  Full-body harnesses, also known as personal

  migrate. Besides, if the bottom layer is wood

  fall-arrest systems (PFAS), may be required by

  P R O T I P

  shingles over skip-sheathing (1-in. boards with

  local building authorities if a roof exceeds a cer-

  spaces between), only half of the new roofing

  tain pitch or if the eaves are more than a speci-

  as you prepare to install roof-

  nails would be likely to hit sheathing. Additional

  fied height above the ground. If harnesses are

  ing components, imagine rain-

  layers would be poorly attached and therefore

  required, have someone at the rental comp
any

  water running down the roof. to

  wouldn’t last. Also, multiple layers of shingles put

  demonstrate correct use.

  prevent water running under-

  a tremendous strain on framing and sheathing.

  neath underlayment, flashing, or

  Knee pads, sturdy ones with integral plastic

  shingles, roofing materials

  cups, will spare you a lot of pain. In addition, get

  upslope must always overlay

  a foam kneeling pad such as those gardeners use;

  those below.

  it will allow you to sit or kneel while shingling

  and will protect shingles from abrasion.

  a pneumatic nailer, which you can rent, speeds

  Roof Longevity

  the job along. Have the rental company recom-

  mend nails and explain the nailer’s correct use.

  MATerIAL

  LOngevITy (years)

  shingling hatchets in the hands of a pro can fas-

  slate and tile*

  

  80

  ten shingles almost as fast as a pneumatic nailer.

  Miscellaneous tools

  Wood shingles or shakes

  include a utility knife with

  

  30–40

  hooked blades, a straightedge or framing square,

  metal

  

  40–50

  a hammer, a chalkline, a tape measure, caulk

  20–50 (depends

  guns, work gloves, safety glasses, and hearing

  asphalt shingles

  

  on warranty

  protection.

  three-ply built-up roof

  

  15–20

  Preparing to Install

  four-ply built-up roof

  

  20–25

  a New Roof

  *Underlayment quality also determines how many leak-free

  Daily temperatures on a roof or in an unventilated

  years you can expect. With 15-lb. building paper underneath,

  attic can swing from 50°F to 150°F, thereby caus-

  a tile roof might start leaking in 15 years; modified bitumin

  ing tremendous expansion and contraction of

  under tile could help create an 80-year roof.

  roof materials. Improving ventilation under the

  80

  Chapter 5

  sheathing and rafters show extensive water

  broom) and roll the lawn to locate roofing nails—

  damage. When you can’t determine exactly

  before your lawn mower does it for you.

  what’s been causing leaks, it’s time to strip. The

  And don’t forget the inside of the attic. Spread

  previous roofers may have installed flashing

  plastic tarps over attic floors, especially if there’s

  incorrectly or not at all. Or roofers may have left

  insulation between the joists. During tearoff, an

  tired old flashing in place. Whatever the cause, if

  immense amount of debris and fine dust falls

  the remedy is stripping back extensive sections of into an attic. Unless you catch it in plastic and

 

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