Renovation 4th Edition

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Renovation 4th Edition Page 23

by Michael Litchfield


  right; otherwise, you’ll be reaching across your-

   follow a standard nailing schedule of four nails per shingle or six nails for high-

  self continually. Left-handers, of course, should

  wind areas. trimmed-down shingles must have at least two nails. place the first and last

  start right and work left.

  nails in from the edges at least 1 in. all nails must be covered by the shingle above.

  There are many ways to lay out and install

  shingles. If you’re installing laminated shingles, a

  pyramid pattern is best. With this method, you

  precut a series of progressively shorter shingles,

  based on some multiple of the offset dimension.

  Nailing schedule: four nails per shingle is

  standard; use six nails for high-wind areas. Because each successive course is, say, 5 in. or

  Trimmed-down shingles must have at least

  6 in. shorter, the stepped pattern looks like a

  two nails. Place the first and last nails in

  pyramid. Typically, pyramids start along a roof

  from the edges at least 1 in. All nails must

  be covered by the shingle above.

  edge, with the first shingle in each course flush to

  the rake starter strip.

  Once the pyramid is established, the job goes

  quickly. Just place a full shingle against each step

  in the pyramid and keep going. Because the off-

  set is established by those first shingles, you can

  install full shingles until you reach the other end

  of the roof. But most roofers prefer to work up

  and out, maintaining the diagonal. If there are

  color variations among bundles, they’ll be less

  noticeable if the shingles are dispersed diagonally.

  The frequency of a pyramid pattern’s repeat-

  ing itself depends on how random you want shin-

  gles to look. Traditionally, patterns repeat every

  94

  Chapter 5

  Roofing jacks

  Roofing jacks provide safe platforms on slopes. typically, install a pair of jacks

  for every six to eight courses. to attach the jacks, level the pair by aligning the

  jacks to horizontal chalklines, and drive two 10d galvanized common nails

  through each jack into rafters. (jacks nailed only to sheathing are unsafe.) place

  nails above the fastener line on the shingle because the nails will stay in place

  after jacks are removed.

  if you space each pair of jacks 8 ft. apart horizontally, they can be spanned

  by 10-ft.-long planks that allow a 1-ft. overhang on each end. however, install

  the two shingle courses above the jacks before you add the plank; otherwise, the

  plank will prevent you from nailing those courses. to prevent a plank from sliding

  out of a jack, nail through the hole in the front of the jack arm into the plank.

  plank-and-jack removal is a two-person job, especially in windy weather.

  above all, play it safe. first, move the plank to a secure location. to remove a

  jack, sharply hammer its bottom upward, thereby driving the slotted jack holes

  off the 10d nails. then, while being careful not to disturb the overlapping shin-

  gles, slide the jack out. it’s a good idea to drive jack nail heads flush, but it’s not

  imperative. to drive them flush, slide a flat bar under the overlapping shingle,

  placing it atop the nail head, then strike the bar’s handle with a hammer. this

  may require several blows.

  fourth course, that is, every fourth course begins

  with a full shingle. Whatever pattern you choose,

  trimmed pyramid shingles should be at least 8 in.

  Rake drip-edge

  zzzzzz Laying out three-tab shingles

  wide; otherwise, they’ll look flimsy.

  36 in.

  Keeping things aligned. As you work up the

  30 in.

  roof, align the tops of shingles to horizontal

  chalklines. Chalklines wear off quickly, so don’t

  snap them too far in advance; snapping

  Vertical

  chalklines each time you roll out a new course of

  offset chalklines

  building paper is about right. However, to get the

  Horizontal

  measuring done all at once, you can measure up

  layout chalklines

  from that original 12-in. line and use a builder’s

  crayon to mark off exposure intervals along the

  rake edges on both ends of the roof, and then

  snap chalklines through those marks later.

  Alternatively, if you snap chalklines only every

  Cutouts

  second, third, or fourth course, use the gauge on

  the underside of your pneumatic nailer or on

  Three-tab shingle

  your shingle hatchet to set exposures for inter-

  vening courses. If your shingling field is inter-

  rupted by dormers, always measure down to that

  original 12-in. line to reestablish exposure lines

  above the obstruction.

  Finally, if the ridge is out of parallel with the

  3/4-in.

  1-ft.-wide

  3/4-in.

  eaves by more than 3⁄4 in., stop shingling 3 ft. shy

  overhang

  tabs

  overhang

  of the ridge and start adjusting exposures so that

  the final shingle course will be virtually parallel

  Aligning three-tab shingle cutouts can be as easy as snapping two

  with the ridge. For example, if there’s a discrep-

  vertical chalklines 6 in. apart. Because individual shingle tabs are

  ancy of 11⁄2 in., then at 3 ft. below the ridge, you’ll

  1 ft. wide, a 6-in. offset wil line up shingle cutouts every other course.

  Roofs

  95

  need to reduce exposures on the narrow end of

  the roof by 1⁄4 in. in each of six courses.

  Rake drip-edge

  Underlayment

  Valleys. Both open valleys (in which metal valley

  zzzzzz using a pyramid pattern Layout

  flashing is exposed) and closed valleys should be

  Chalked

  lined, as described in “Underlayment” on p. 82.

  exposure lines

  Closed valleys are more weathertight but slower

  to install, so they’ve become less popular. Open

  valleys are faster to install and better suited to

  laminated shingles, which are too bulky and stiff

  to interweave in a closed valley.

  Once you’ve installed valley flashing, snap

  Factory ends

  chalklines along both sides to show where to trim

  Control line 12 in.

  above drip-edge

  overlying shingles. Locate chalklines at least 3 in.

  Starter strip

  back from the center of the valley; oncoming

  shingles cover valley flashing at least 6 in. When

  nailing shingles, keep the nails back at least 6 in.

  from the valley centerline—in other words, 3 in.

  back from the shingle trim line—so nails can be

  covered by shingles above. To seal shingle ends to

  Fascia

  board

  the metal flashing, run a bead of roofing cement

  Trim excess

  and use on opposite

  Starter strip

  under the leading edge of each shingle, and put

  rake edge.

  dabs of cement between shingles. Ideally, you

  Start with
full shingle.

  should not nail through the metal at all, but that

  could leave an inordinately wide area of shingles

  Shingles overhang

  unnailed. Besides, self-adhering waterproofing

  drip-edge by 3/4 in.

  membranes beneath the metal flashing will self-

  seal around the nail shanks.

  A pyramid pattern is best for installing laminated shingles that don’t have distinct

  As a shingle from each course crosses a chalk-

  cutouts. As you build the pyramid along the rake edge, trim excess from the rake end line, use a utility knife to notch the shingle top so a factory end always leads off each course. Align shingles to horizontal chalklines and bottom. Then flip the shingle over and, using you snap, not to lines printed on building paper.

  a straightedge, score the back of the shingle from

  P R O T I P

  as shingles run diagonally into

  an open valley, their leading

  edges often end in sharp points,

  under which water can run. to

  prevent that, use a utility knife

  with a hooked blade to remove

  about 1 in. of the point, cutting

  perpendicular to the bottom

  edge of the shingle.

  1. Carefully align the first shingle (which is uncut) to

  the edges of both eaves and rake starter strips.

  2. Shorten the second shingle in the

  pyramid by the offset dimension. Use

  the gauge stop on the bottom of the

  pneumatic nailer to establish the

  correct exposure between courses.

  3. At this point, you could run courses all the way across

  the roof, but most roofers prefer to work up and out,

  maintaining the diagonal. Although this veteran roofer

  didn’t need to snap horizontal chalklines across the roof

  to keep courses straight, novices should.

  96

  Chapter 5

  new Roofing over old

  although placing new roofing over old may be allowed by some codes, “roofovers” tend

  to be inferior. as noted earlier, you must strip a roof if there are two or more layers or if

  existing shingles are curling.

  Before beginning, replace or flash over old flashing as follows:

   use aviation snips to cut away flashing around plumbing vents.

   use a cold chisel to remove chimney counterflashing.

   along the eaves, install a new drip-edge over the butt ends of existing shingles.

   along the rakes, install a new j-channel drip-edge, which wraps around the old

  rake flashing and starter courses.

   Leave the old valley flashing in place, and install new over it.

  This classic wood shingle roof has an open valley. Shingle

  to level out an existing asphalt-shingle roof, rip down (reduce the height of) two

  caps cover the roof hip.

  courses of shingles, as shown in the drawing. Because asphalt shingles are routinely

  exposed 5 in., rip down the first strip (the starter course) so that it is 5 in. high. then

  notch to notch. Or, to speed installation, run

  lay it over the original (old) first course so that the strip is flush against the butts of

  shingles into the valley, and then when the roof

  the original second course above. next, rip down a second strip (second course) 10 in.

  section is complete, snap a chalkline along their

  high, and put it flush against the butts of the original third course. you now have a

  ends to indicate a cutline. To avoid cutting the

  flat surface along the eaves. the third course of new shingles—and all subsequent

  metal flashing underneath, put a piece of scrap

  shingles—need not be cut down, just butted to an original course above and nailed

  metal beneath shingle ends as you cut, using a

  down. use 11⁄2-in. roofing nails for roofovers—or whatever length is necessary to reach

  hooked blade in a utility knife or snips.

  the sheathing.

  Finally, codes in wet or snowy regions may

  require that valleys grow wider at the bottom.

  In that case, move the bottom of each

  chalkline away from the valley center at a

  rate of 1⁄8 in. per ft.

  zzzzzz new shingles over old

  New rake drip-edge

  Old roofing

  Third course

  Second course

  12 in.

  Starter course

  10 in.

  5 in.

  Closed-cut valleys are faster to install than woven ones

  because you don’t need to weave shingles from two

  New eaves drip-edge

  converging roof planes at the same time.

  When installing a new roof over an old one,

  avoid a wavy-looking job by reducing the height of

  the first two courses to establish a flat surface.

  Roofs

  97

  P R O T I P

  finishing the Ridge

  ripper under the shingles and gently slicing

  through the adhesive strips (see photo 1 on

  Where composition shingles converge at the

  p. 150). It’s best to do this when shingles are cool

  if you mistakenly shoot a nail

  ridge, they should be capped to keep out weather and the adhesive is somewhat brittle and easier

  through a shingle, cover the nail

  elements and create a neat, finished joint.

  to break. If you attempt this when the roof is hot,

  head with roofing cement or ure-

  Traditionally, roofers created cap shingles from you’re more likely to tear the shingles. Actually

  thane caulk and drive a new nail

  leftover three-tab shingles, by extending the cut-

  within 1 in.

  working with the shingles—lifting them to

  outs across the width of the shingle. Each stan-

  remove nails or slide in new shingles—is best

  dard shingle yielded three cap shingles, which

  done when the shingle is warm and flexible.

  the roofer gently folded to straddle the ridge and

  To remove a damaged shingle, raise the shin-

  cover the tops of oncoming shingles. Two roofing gles above and tear the old one out. If it doesn’t

  nails per cap shingle are sufficient, with the nail

  tear easily, use a utility knife to cut it out.

  heads covered by successive shingles—until the

  Remove the nails that held the damaged shingle

  last cap shingle, which gets four nails. Two

  by inserting a shingle ripper against the nail

  important details: Cap shingles must be placed so shafts and prying up. Keep in mind that those

  that prevailing winds blow over shingle overlaps,

  nails are actually going through two shingle

  rather than into them, which could lift and loosen courses—the one you’re trying to remove and the

  them. And roofing nails must be long enough to

  top of the course below. If you extricate the shin-

  penetrate the several shingle layers at the ridge

  gle and the nails don’t come up with a reasonable

  and sink into the sheathing.

  amount of trying, just knock the nails down with

  These days, there are more options for cap-

  your hammer and a flat bar.

  ping the ridge, notably preformed ridge and hip

  Fill old nail holes with roofing cement, and

  shingles. These specialty shingles come prefolded slide the new shingle into place. Gently lift the

&n
bsp; and so are unlikely to split along the fold—a real

  course above, and position nails so they’ll be

  problem with laminated or luxury shingles,

  overlapped by that course. Once you’ve inserted a

  which are thicker and stiffer than three-tab vari-

  new shingle, use the flat bar to help drive them

  eties. Most composition shingle makers offer pre-

  down, placing the flat bar atop the nail head and

  formed ridge shingles to match the shingles you

  striking the bar with a hammer.

  use in the field. There also are plastic and metal

  ridge caps, which, although clearly a different

  material, can usually approximate the color of

  Wood Shingles

  field shingles.

  There’s romance in wood shingles. Despite

  Lastly, many modern roofs have vents along

  wood’s tendency to cup, split, rot, grow moss,

  the ridge, which allow air to rise and exit the

  and catch fire, people still love it. Insurers, how-

  house. In tandem with soffit vents, ridge vents

  ever, don’t because it can catch fire and often

  encourage a flow of air beneath the roof deck,

  refuse to insure homes with wood roofs in fire-

  helping to keep the attic cooler in summer and

  prone areas. Keep in mind, too, that wood shin-

  lessening the chance for ice dams in winter. To

  gles take longer to install than asphalt shingles,

  install a ridge vent, cut sheathing back at least

  so labor will cost more. Regarding durability,

  1 in. on either side of the ridge board as shown in Eastern white cedar and Western red cedar are

  the bottom drawing on the facing page. Run

  about the same—though each region’s noisier

  underlayment and shingles to the edge of the

  authorities assert that its shingles last longer. As

  sheathing. Then nail the ridge vent over the open- white cedar shingles age, they turn silver; red

  ing, straddling the shingles on both sides. In

  cedar shingles turn dark brown to almost black.

  most cases, the ridge vent is then covered by

  cap shingles—with care taken not to block vent

  pRepaRing the Roof

  openings.

  Be sure to read the earlier sections on sheathing,

  underlayment, and flashing. And review the

  asphaLt shingLe RepaiR

  methods of asphalt-shingle installation, for they

  Most roofs are repaired in response to leaks

  have some things in common with wood shingling.

  caused by a missing shingle or, more often, worn-

 

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