other side is a feathery nylon brush
router to cut two slots along each sash stile; set back slots that slides smoothly.
1⁄4 in. to 3⁄8 in. from stile edges.
9. Prime all bare wood surfaces before returning sashes
to their frames. If you have time, paint them now, too.
10. Before reattaching sash cords,
11. As you replace each sash, make sure it glides
12. Once sashes and weights are moving well, close up
lubricate pulley wheels so they won’t
smoothly and weights rise and fall freely.
the wall cavities. If that means renailing interior casing,
squeal.
first pull old nails through the casing. Fill nail holes with
color-matched wood putty, and use a tiny paintbrush to
apply finish just to puttied spots.
Doors, Windows, and Skylights
145
glAzINg
Using a caulking gun, apply a bead of acrylic
latex with silicone around the perimeter of the
Wear safety glasses and gloves when removing
frame. Place the glass in the frame, and press
old glass and putty (glazing compound). Try not
down so it seats evenly in the sealant. Next, use
to damage the sash when removing putty.
a putty knife to push glazier’s points into the
Although a glazier’s chisel will remove most
muntins to secure the glass; space points every
putty, try to soften tougher stuff with a hair dryer 6 in. around the perimeter, using at least two
first. If that doesn’t do it, lay the sash flat and
points per side. Glass in metal-frame windows is
pour a small amount of rubbing alcohol on the
typically held in place by metal spring clips,
putty and let it sit overnight. (Do not combine
which can be reused.
heat and alcohol.) After removing old putty, gla-
When the glass is secure, apply putty. For the
zier’s points, and damaged glass, sand the frame
best combination of skin protection and dexterity,
lightly, using 180-grit sandpaper. Prime and paint wear nitrile disposable gloves for this operation.
bare wood before proceeding.
Scoop out a generous palmful of putty, and knead
To cut glass, pull a glass cutter along a
it until it is soft and pliable. Roll it up into a fat
straightedge as shown in photo 1 below. After
snake, then use your thumb to press the putty
scribing the glass, gently rap the ball end of the
around the perimeter of the pane. You’ll trim
cutter along the underside of the cut until a clear excess putty, so use a lot to ensure a good seal.
line develops. Then, holding the cut line directly
The pros apply putty and trim it in one sweep,
over a table edge, snap the waste portion free. If
but the rest of us should do it in two passes. Once
the waste piece is too small to grasp, use glass
a side has been puttied, rest one point of the
pliers. Cut the glass 1⁄8 in. smaller than the length putty knife on the glass, and holding the blade at
and width of the frame opening.
1. After removing old glass, cleaning 2. Rap the ball end of the cutter along the underside of
up the frame and priming it, cut
the cut until a clear line develops. Then, holding the
replacement panes 1⁄8 in. smaller than cutline directly over a table edge, snap the waste portion
the dimensions of the opening.
free.
Holding a glass cutter perpendicular
to the pane, pull it evenly along a
3.
straightedge. Safety glasses and
Apply a bead of acrylic latex with silicone around the
gloves, please!
perimeter of the frame lip on which the glass will rest.
Press the glass into the sealant so it beds evenly.
4. Drive glazier points around the perimeter of the
5. When the glass is secure, apply putty generously to
opening, using at least two points per side. Here, a glazing each side, pressing it into the frame. Pull the blade
gun makes the task easier.
through the putty to cut away excess, holding it at a
45° angle to the glass.
146 Chapter 6
Cutting
SeleCtINg A SkylIgHt
laMInaTeD
Consider a number of things when buying a sky-
glaSS
light, not least of which is the manufacturer.
Although sizes have become pretty much stan-
Laminated glass is increasingly popular for its
dard, quality varies greatly—so ask local contrac-
impact-resistance and sound-deadening quali-
tors or lumber suppliers which brands they pre-
ties. Because there is a plastic core between the
fer. Here are a few aspects to investigate:
two layers of glass, however, there’s a trick to
Do you want ventilating (openable) or
cutting it. Using a glass cutter, score both sides
fixed (closed) skylights? Skylights that open
of glass. Then squirt a small amount of ethyl
can vent excess heat. And turn-tilt models
alcohol along the cut on one side and light it.
pivot so they’re easy to clean.
This melts the plastic core. Then, using a pair of
Is it energy efficient? Most units come
glass pliers, snap away the excess.
with doubled thermal-pane glass, but units
should also have a thermal break to minimize
loss by conduction. A metal frame that’s
continuous (inside to out) will wick out a lot of
indoor heat. A better bet is sealed wood.
a 45° angle to the glass, pull the knife steadily to
cut a furrow through the putty.
Does it have step-flashing along its sides
Touch up corners after removing trimmed
(desirable for shingle roofing) or strip
putty. If putty doesn’t stick, either you’re holding
flashing? Strip flashing must be caulked to
the knife handle too high or there is dust on the
keep water out—and thus is less reliable. If the
glass. If the problem is the drag of the knife
unit is wide (more than 32 in.), does the maker
blade, a bit of saliva on the blade will lubricate it. supply a cricket to deflect water around the
Allow the putty to cure for a week before paint-
skylight head or will you need to have one
ing, then overpaint it slightly (onto the glass) to
fabricated?
seal the putty joint.
Does the unit have tempered glass?
That’s an important consideration if a tree
Instal ing a Skylight
limb overhangs your roof. Your building code
may require such glass.
By letting in light, skylights can transform a
room, making a bathroom seem larger, a kitchen
warm and cheery, or a bedroom a place to watch
the stars. And because of marked improvements
in flashing and quality control, skylights can be
installed without fear of leaks from the outside or
of excessive heat loss from within.
Where you put the skylight is partly aesthetic
and partly structural. In a kitchen, installing the
skylight in an east-facing roof w
ill help it catch
the morning sun. If placed in a hallway, even a
small unit provides enough light to let you do
without electric light during the day. In a bath-
room, privacy is the main issue. Avoid skylights
in south-facing roofs unless you’re designing for
passive solar gain; you’ll roast in summer.
Similarly, skylights in west-facing roofs may cre-
ate too much heat in the South and Southwest
United States. Avoid skylights that straddle a
ridge because they are difficult to flash and
likely to leak.
Skylights dramatically change rooms. Because drywall
joints and nail holes will be illuminated, too, apply joint
compound generously and sand carefully. Heat buildup in
the lightwell can cause compound to shrink, so you may
need to apply an extra coat.
Doors, Windows, and Skylights
147
If the unit will be installed beyond reach,
Most skylights are sized incrementally to fit
how easy is it to open and close? Remote-
between rafters spaced 16 in. or 24 in. on center,
controlled units with motors can be
so they routinely come in 24-in., 32-in., and
programmed to open at a given temperature
48-in. widths. Skylights 32 in. wide are the most
and shut when an electronic sensor detects
popular size because you need to cut only one
rain, but they are more expensive and more
rafter to accommodate the unit. Velux®, for
temperamental than manually operated
example, has several models whose inside curb
skylights.
dimensions are 301⁄2 in. wide—the same distance
P R O T I P
Can you get units with screens, blinds,
between rafters spaced 16-in. on center, if one
shades, or polarizing tints? Low-e coatings
rafter in between is removed. Aligning the inner
the area under the roof is a
selectively admit light while reflecting heat.
faces of skylight curbs and rafters also makes
messy place to work, especially
Note: There are different coating types for cold
installing drywall much easier. Attached to the
if the ceiling’s insulated. Use
and hot climates, so ask your supplier which is
roof sheathing with L-shaped mounting brackets,
sheet plastic to isolate the area
appropriate for your area.
the sides of Velux units sit right over rafters.
below the lightwell and a dust-
pan and trash bags to store the
FRAMINg A SkylIgHt OPeNINg
SIzINg SkylIgHtS
insulation for reuse. Wear gloves,
a dust mask, and goggles. to
This section provides general guidance related to
Folks often order skylights larger than they need.
protect your head from roofing
framing procedures shown in the photos. Usually,
Keep in mind that even the smallest unit bright-
nails sticking through the
it doesn’t matter whether you cut ceiling joists or
ens a room greatly. Moreover, much of the light
sheathing, wear a hard hat.
rafters first, as long as they’re adequately sup-
gain comes from reflections off the sides of the
(you should already have gotten
ported. Some pros prefer to frame the lightwell
lightwell (or light shaft), which is why wells are
a tetanus shot.)
completely before opening up the roof. Others
usually painted white. You can increase the
install the skylight first and work down from there.
amount of light markedly by flaring out the sides
of the well. If you need more light than one nar-
Insulation. Remove the ceiling insulation. Then
row skylight will yield, consider ganging several,
disconnect and cap any wires and pipes that will
side by side, in adjacent rafter bays. Smaller sky-
need to be rerouted around the opening. (Use a
lights are easier to frame, and the fewer rafters
voltage tester to be sure the power is off.) Where
you disturb, the better.
possible, work from a stepladder rather than sit-
Temporary braces support
zzzzzz Skylight Positioning
cut-through rafter.
Doubled headers reinforce
cut rafters, cut joists.
Remove roofing, sheathing.
Bevel top edge of
Plumb lower wall.
these doubled headers.
Rafter
Temporary brace
Strongback
Upper wall at 90°
angle to roof plane
Ceiling joist
Doubled headers
Strongbacks keep
Trim drywall flush
cut-through joists
to doubled headers.
Before you cut anything, take time to think through and lay out the
from sagging.
rough openings and lightwell walls. Also add strongbacks and braces.
148 Chapter 6
ting on ceiling joists; that way, you’ll be less likely
to crack the finish ceiling. The job will go faster if
one worker on a ladder measures carefully and
calls out measurements for headers, trimmers,
zzzzzz Skylight Framing
lightwell studs, and the like to a second worker
on the floor, who does the cutting.
Doubled rafters
Cut-through
Before cutting ceiling joists, support them
rafter
with a strongback, which is a piece of dimension
Lower end wall, sidewall
Upper end wall
lumber nailed to the tops of ceiling joists to keep
studs to come are plumb.
at 90° angle to
them from sagging, as shown in “Skylight
roof plane
Positioning” on the facing page. The strongback
Trimmer rafter
Metal connectors
should run perpendicular to the joist grid, be
(added)
strengthen joints.
placed within 1 ft. of the cut joist ends, and rest
on uncut joists beyond the opening to distribute
the load. To tie the strongback to the joists, you
can use steel hurricane ties (see the bottom
photo on p. 72).
Joists. Cut out the ceiling joists after attaching
the strongbacks. Use a framing square to make
Cut-through
sure the cuts are square. Cut the ceiling joists so
ceiling joist
their ends will be set back 3 in. from the final
opening in the ceiling. This setback ensures that
Doubled ceiling joists
the doubled headers (3 in. wide) at both ends will
be flush with the edges of the finish ceiling. Use
Doubled headers
three 16d common nails to nail the first board of
each doubled header to the ends of the joists you
have cut; nail the second header of each pair to
the face of the first. Once the headers are in
In addition to doubling headers at the ends of rough openings,
place, nail into their ends, through the trimmer
double up rafters and joists running along the sides of openings.
joists. Use steel double-joist hangers for greater
and the lower end wall of the lightwell are plumb.
strength. Then double the trimmer joists along
each side, making sure the nails don’t protrude
into the opening.
shingle spots, and pull out any nails within 1 ft.
roof opening. Cutting out the roof opening is
of the opening. This nail-free perimeter will
relatively easy if the roof pitch is low (5/12 or
enable you to properly flash the skylight curb
less). But if it’s steep, use roof jacks to create a
with building paper or self-adhering bituminous
safe working platform. Once on the roof, snap
flashing. Finally, if you’re installing a skylight
chalklines through the four 16d nails you drove
with L-shaped mounting brackets, cut back the
through earlier, as described in “Skylight: Sloping shingles an additional 11⁄2 in. to 2 in. around the
Roof, Flat Ceiling” on p. 151. Then use a hooked
RO so the brackets can sit on a uniformly flat
blade in a utility knife to score the asphalt shin-
surface and be screwed easily into sheathing.
gles along the chalklines. Scoring allows you to
remove the shingles within the RO without dis-
Framing. Frame the roof opening and the light-
turbing those around the perimeter.
well. Before cutting through the rafters, install
Once you’ve removed the shingles within the
temporary braces to the ceiling joists below;
RO, use a circular saw with a demolition blade
those rafter braces stay in place until the rafters
set to the depth of the roof sheathing. If you’re
are headered off. If the upper wall of the lightwell
skilled, you can use a reciprocating saw with a
will be perpendicular to the rafters, use a framing
bimetal blade to cut through the sheathing, as
square to mark a square cut back 3 in. from
the pro is doing in the top center photo on p. 150, the edge of the opening (a doubled header is
but don’t cut through a rafter while you’re stand-
3 in. wide).
ing on it! Whatever tool you use, wear eye protec-
The lower end of the lightwell is a bit trickier
tion because you’re likely to hit nails. After you’ve to frame because it intersects the roof plane at an
cut around the perimeter of the RO, use a claw
obtuse angle (greater than 90°). Hold a 4-ft. level
hammer or a flat bar to pry out the sheathing.
plumb against the lower edge of the roof RO,
Renovation 4th Edition Page 34