New Orleans is a great place to be a restoration carpenter.
With 62 inches of annual rainfall and humidity levels that
hover around 90 percent for much of the year, I'm guaranteed a
steady stream of jobs repairing rotted windows and doors. Much
of my work involves 100-plus-year-old homes; fortunately, given
the high quality of their old-growth wood, I can make most of
these repairs with a little epoxy.
But the millwork in newer homes is often a different story.
Some of my clients with relatively new homes require extensive
repairs after only eight or 10 years. While fighting rot in
this region's climate sometimes feels like a losing battle,
I've developed some techniques — and adopted some
specialized products — to help new millwork and repairs
on existing windows and doors last as long as possible.
Protect Vulnerable Wood
One of the major reasons newer doors and windows start rotting
so quickly, I believe, is that the quick-growing white pine (or
its variants) used in most factory-made doors and windows is
not suitable for the Deep South. If the wood contains any
treatment at all, it's a water-repellent, not a preservative,
so when this fast-growing pine starts going bad, it takes off
at a gallop (see Figure 1). That is why I carefully back-prime
everything I can on new doors and windows, seal all end grain
with paint or special epoxy coatings, and raise the units
slightly so they're not sitting directly on horizontal surfaces
that could hold water. Since the bottom 16 inches of jambs and
casings are especially vulnerable, I focus most of my attention
on this area.
Figure 1.After only eight years,
this door frame is well on its way to becoming compost (left).
The damage to the window (right) is typical in New Orleans' hot
and humid climate. The author uses a number of techniques
— including treating with preservatives, back-priming,
and epoxy-coating end grains — to prevent rot in both new
and existing doors and windows.
For added insurance against rot, the
author often soaks new and repaired pieces in a borate-based
preservative like Bora-Care.
If I have enough time and new units to justify building a
dipping trough, I first soak the bottom 3 to 4 inches of each
unit in a borax solution such as Tim-bor or Bora-Care (Wood
Care Systems, 800/827-3480, www.ewoodcare.com; Figure 2). Then I seal
these areas with West System 105 Epoxy Resin and 207
Special-Coating Hardener (West System, 866/937-8797,
www.westsystem.com) or with Corlar 25P or
26P two-part epoxy coatings (DuPont, 800/438-3876,
Figure 3.Two-part epoxies — like these from
DuPont and West System — dry faster than conventional
paints and provide better protection against water penetration.
Because epoxies break down when exposed to UV light, it's
important to cover them with a protective top coat of
The two Corlar products are similar, but 25P — an epoxy
mastic — contains more solids and goes on thicker than
26P. The 25P is great for protecting end grain, and I use it
for applications like porch flooring, where a thicker coat is
an advantage. The thinner 26P penetrates and brushes out
better; I use it as the primer for almost all of my rot-repair
work. One drawback to Corlar 26P, though, is its induction
time. After mixing, you have to let it sit for about an hour.
25P doesn't require the wait.
(Note: DuPont has changed the names of all its industrial
coatings. Corlar 25P is now Corlar 2.1 ST and Corlar 26P is
Corlar 2.8 HG. However, the former names are still commonly
used at the dealer level.)
Both types of Corlar are mixed one-to-one with their activators
and thinned with MEK (methyl ethyl ketone). I buy the epoxy
base and its activator in gallon containers from a DuPont
Industrial Coatings dealer for about $85, which makes two
gallons of the coating. And I always wear a respirator and
nitrile gloves while I'm using these substances.
I use Corlar 26P to coat the bottoms of frames and casings,
usually up to about the first finger joint. Where finger joints
are within 12 inches of a horizontal surface, I carve out a
small "V" directly over the joint with a utility knife (Figure
4) and skim it over with WoodEpox epoxy putty (Abatron,
Figure 4.Finger joints on doors and windows are
one place where rot can quickly gain a foothold, so the author
creates a small recess with a utility knife and then skims over
the joint with two-part epoxy putty to create a more
I also like to pry factory-installed brick mold away from
frames just enough to coat the back side of the bottom inch or
two of the molding. Then I feather out the top edge and rough
up the dried epoxy with 220-grit sandpaper, so an alkyd primer
Sometimes I use West System 105/207 epoxy in place of the
Corlar because, depending on the hardener used, it dries in as
little as a half-hour, making it a better choice when I have
only one or two repairs to make. Otherwise, I prefer the Corlar
because it sands more easily and has a longer working
Let Air In and Water Out
Whenever possible, I try to install new doors and windows in
such a way that they have a chance to dry out. For example, I
like to attach 1/4-inch-thick pressure-treated shims to the
bottom of door thresholds, or place door and window units on
strips of Cor-A-Vent S-400 (Cor-A-Vent, 800/837-8368,
www.cor-a-vent.com). Designed primarily as
a soffit vent, Cor-A-Vent S-400 is made from a 1-inch-tall by
11/2-inch-wide stack of plastic corrugations held together with
large staples. After prying apart the staples, you end up with
six individual corrugations. Each corrugation can be used
singly to create a 1/8-inch-high vent channel, or the stack can
be left as high as needed (Figure 5). Because Cor-A-Vent is
made from rigid plastic, it also offers some structural
support. To keep swarming Formosan and dry-wood termites from
crawling through the holes, I wrap a piece of aluminum screen
around the back of the Cor-A-Vent before installing it.
When I'm working on a new installation and the door threshold
has to sit on the floor for some reason, I commonly trim 1/8
inch to 1/4 inch off the jamb bottoms so they're not touching
the subfloor, making them less likely to wick water. I don't
remove the jambs from the threshold; I just take a little off
the bottoms with a circular saw (or, if the door is already in
place, a reciprocating saw). After coating the end cuts with
Corlar 25P, I fill this gap with Cor-A-Vent or bronze screening
(Blaine Window Hardware, 800/678-1919,
www.blainewindow.com) to keep out bugs and
create a combination weep and vent at the bottom.
Figure 5.Made from stacked sections of corrugated
plastic, Cor-A-Vent S-400 is primarily designed for soffit
venting (top). But once the staples are removed, individual
sections can easily be separated from the stack and placed
under windows or doors, where they promote drying (bottom
On both new installations and repairs, I'll frequently remove
the brick mold and cut it 1/8 inch to 1/4 inch short, then
attach screening to the trimmed and coated bottoms, doubling it
over and stapling it in place with stainless steel staples
(Figure 6). Folding the screening over a round pencil before
installation gives it a nice shape.
Before installing a door unit, the author
likes to remove the brick molding, cut 1/8 inch to 1/4 inch off
the bottom ends, coat them with epoxy, and staple bronze
screening to them. Holes drilled in the trim at an upward angle
and covered with small thimble vents allow interior moisture to
drain while keeping out bugs.
On repair jobs where removing the casing would be difficult, I
trim it in place with a Fein MultiMaster, then pry it loose
enough to back-prime the bottom inch or two with Corlar 25P.
Then I insert a rolled piece of bronze screening or
Since the untreated wood stock under the aluminum threshold
found on many inexpensive doors is bound to cause problems
later on, I'll often replace it with pressure-treated stock or
a piece of fiber-composite decking before installing the door.
This isn't as much trouble as it sounds. After removing the
sill from the door unit, I pry loose the rot-prone pine filler
and replace it with a duplicate made from pressure-treated
stock, which I secure to the aluminum sill with small
On metal exterior doors, the wood perimeter — especially
at the bottom — will cause problems if exposed to water.
If the door has a sweep with a solid plastic top, this further
traps moisture inside the door. On both new doors and ones that
I'm repairing, I usually pry the weather sweep loose at the
ends, so I can epoxy-seal the end grain on the stiles and on
the joint where the stiles meet the bottom rail. Then I bed the
top of the sweep in caulking.
If I'm working on a number of similar doors, I remove their
sweeps entirely and cut slots into their solid tops to promote
drying, using a 1/8-inch straight-cutting bit in a die grinder
guided by a jig. (You could also use a small router or laminate
trimmer.) Another option is to drill a series of holes into the
base of the sweep before remounting it.
To provide ventilation to the interior of the bottom rails, I
drill 3/8-inch-diameter holes on 6-inch or 8-inch centers in
the bottom rail from the interior side of the door. I cover the
holes with 3/8-inch thimble vents (Midget Louver Co.,
800/643-4381, www.midgetlouver.com; Figure 7).
Figure 7.The wood bottoms on steel doors are
vulnerable to rot. The author first removes the damaged wood
and replaces it with pressure-treated stock, then drills a
series of holes in the interior side of the door to promote
drying. Small thimble vents inserted into these holes prevent
insects from nesting inside the door.
A good way to prevent rot at the bottom of doors and windows is
with Impel Rods (Wood Care Systems, 800/827-3480,
www.ewoodcare.com). Inserted into drilled
holes, the compressed borax pellets remain inert as long as
they stay dry; when they get wet, they slowly dissolve,
protecting the wood from rot. The manufacturer claims they last
a minimum of eight years.
Though expensive (a 24-count box of my favorite 1/3-by-1-inch
size sells for $25), these little jewels offer protection in
locations that would otherwise be very hard to address. For
example, I'll insert two or three of them into a single hole
drilled in each door stile, and use two or three more in
another pair of holes drilled in the bottom rail. I also
install rods at the bottom of jambs and casings, and in window
sash and sill horns, covering the holes with either wood plugs
and polyurethane glue or with WoodEpox. These rods allow you to
put protection where it's needed most. If a rot-damaged area is
addressed soon enough, you can usually repair it with epoxy and
install the rods without removing the piece.
Window sash are like small doors: No matter how they operate,
their bottom corners are vulnerable to rot. If their sash are
fixed, I insert short Impel rods into face surfaces to protect
the stiles' bottom end grain and the rails' side end grain
Figure 8.Made from compressed borax and available
in different sizes, Impel Rods (right) can prevent rot.
Inserted into vulnerable areas in windows and doors, the
dowel-shaped pellets slowly dissolve when they're exposed to
moisture, protecting the wood (left). The author uses a
two-part epoxy wood filler — the same material used for
repairs — to cap the holes.
Special Solutions for Windows
The area where jambs and casings meet window sills is a
potential trouble spot. In new construction or where it's
possible to trim the casing short, I leave a 1/4-inch to
1/8-inch gap where the casing meets the sill and fill it with
Cor-A-Vent or screening. Another option is to drain these joint
intersections with 1/4-inch angled weep holes that come out
just behind the casing and out the bottom of the sill just past
In locations with especially severe weather, I also drill a
series of 1/4-inch holes in the bottom rail of sash to drain
away any water that penetrates behind stops. I epoxy-coat
drilled holes with a long cotton or foam swab or with a
1/4-inch flux or artist's brush, and then cap them with a small
thimble vent (Figure 9).
Figure 9.The bottoms of doors and windows are
natural collection spots for moisture, but tiny vents allow the
water to drain. Held in place by friction, the vents come in
3/8-inch and 1/4-inch sizes.
To make a long-lasting caulk joint on long horizontal joints
— for example, where a subsill meets a sill — I cut
a slot with a special tool called a corner grooving machine
that's designed for installing weather stripping (Resource
Conservation Technology, 410/366-1146,
www.conservationtechnology.com). Instead of
foam backer rod, I use bulb weather stripping from the same
company to fill the slot before caulking, which gives the joint
flexibility and improves adhesion (Figure 10).
Figure 10.Designed for retrofitting weather
stripping, this specialty tool cuts slots that are the perfect
size for a caulked joint (left photos). The same manufacturer
also makes the weather stripping that the author uses as a
backer rod (bottom right).
If any repairs to the sash are needed, I use either Abatron's
LiquidWood/WoodEpox system or West System adhesive epoxy,
depending on how structural the repair needs to be (West System
is stronger, but harder to sand). After making repairs and
sanding everything, I apply a coat of West System 105/207 epoxy
and a coat of DuPont Corlar 26P epoxy enamel. The 26P is
applied when the 105/207 goes into the green stage — that
is, when it is tack-free, but not fully hard — which
eliminates the need to key sand the fully hardened 105/207 for
good adhesion of the subsequent coat. This technique also works
when using West 105 with alkyd or latex primers.
Replacing Window Stops
Some factory wood windows come with wooden glazing stops on the
exterior. The ones I've seen aren't back-primed, and neither
are the sash, a recipe for disaster in my climate. If the
windows are getting enough weather for me to be there making
repairs, I figure that at the very least I should pull off the
bottom stops for inspection. If they are in good shape, I
back-prime both surfaces with epoxy and reinstall them using
stainless steel brads. If the stops show even a little rot,
they go into the trash can.
While it would be best to replace all of the factory stops, the
top and side ones are generally in much better shape because
they dry more easily. Granted, it would make sense to remove
them, too, for back-priming, but the factory usually attaches
them with staples, which are often rust-encrusted, making it
difficult — if not impossible — to extract the thin
stops without breaking them. If there is no obvious damage, I
just leave them in place.
Discarded stops could be replaced with glazing putty, but wood
stops look and perform better, so I usually make new ones out
of mahogany. To aid drainage, I give them a steeper 10- or
15-degree pitch and increase their width as much as possible.
After sanding the stops, I apply one coat of West epoxy and one
coat of Corlar 26P to all sides. To eliminate the water pockets
that miter joints create, I slide the bottom stop under the
sides, essentially making a coped joint at the corners (Figure
11). I use a piece of new stop to mark the side stops for
trimming, then cut them in place with a sharp utility knife. As
I install the stops, I coat any exposed end grain with Corlar
25P epoxy. Gently bending the new stop upward in the middle
lets it slip into place.
Figure 11.Mitered stops hold water, so the author
copes new stops at the corners for better drainage, cutting the
vertical stops — which are usually left in place —
with a utility knife. Once installed, the new stops are sealed
to the glass with silicone, the front edge is caulked with
polyurethane, brad holes are filled with epoxy, and then the
entire assembly is given another coat of Corlar
If windows have true divided lights, the mullions are a weak
link. Since most failures occur when the putty pulls away from
the glass, the upward-facing mullions are most at risk.
Wherever I find failed glazing compound, I remove it, coat the
underlying wood with epoxy, and replace the putty with
custom-made wood stops.
I used to bed new stops in glazing putty, but lately I've been
using Resource Conservation Technology's glazing gaskets,
because I've never found a glazing putty that lasts more than
two years (Figure 12).
After filling brad holes with epoxy putty and sanding, I give
the top surfaces of the new stops another coat of 26P. When
it's no longer tacky, I apply a coat of alkyd or latex primer
so I don't have to key sand. (A word of caution: If you apply
primer too soon, it will puddle and you'll have to key sand and
apply another coat.) Then I caulk the front edges with
polyurethane and, after the final top coat, run a bead of Dow
795 sealant (Dow Corning, 989/496-7881,
www.dowcorning.com) where the stops meet
glass. If I haven't used glazing gaskets for some reason, I
apply 1/8-inch Scotch Fine Line masking tape (3M, 888/364-3577,
the glass as a bond breaker.
When the bottom stops on
true-divided-light windows start showing the first signs of
water damage, the author replaces them with wider versions cut
from rot-resistant mahogany. Made with a steeper slope to aid
in drainage, new stops are coated on all surfaces with two
coats of epoxy. The black material on the front of the stop is
a self-stick EPDM glazing gasket that the author uses instead
of glazing putty.
It's worth mentioning that all this extra effort to prevent
doors and windows from rotting away is largely unnecessary when
the building has sufficient overhangs or some other protective
cover for doors and windows — something I'm always
stressing to architects and designers.Michael Davisis a restoration carpenter in New