I have an room addition with a gable roof that is offset about 8
inches from the existing roof (i.e., lower than the roof on the rest
of my cabin). The existing gable exterior is T1-11 siding. When I
install flashing at the point where the new roof meets the old gable,
do I caulk around the point where the exposed portion of the flashing
where it meets the gable, or is it better to cut a kerf in the T1-11
gable, insert the flashing into the kerf, and caulk?
Something like this:
Gable 3 Angled Flashing
| <--- cut a kerf here | <---insert top angle into kerf
On 20 Jan 2004 08:16:05 -0800, email@example.com (Dave) wrote:
if there's a drip edge available from the old roof tuck the flashing
under that. depending how much overhang the roof above has and whether
the gable faces incoming storm winds the water tightness needed could
vary. probably this should be flashed to the top- caulking the upper
edge of a flashing is asking for trouble.
Go with the kerf method, but first step flash up both sides as you shingle
as per standard roofing procedure. Then bend a piece of flashing or break
metal that fits in the kerf and folds down over the step flashing and run
that up both sides providing a nice clean finished look and absolute leak
protection. If done right I can guarantee this will not leak, ever.
For the small amount you're dealing with (8" height) rip the siding out
when you strip the old roof. (You are stripping it, right?) Install new
step flashing on to the studs or sheathing and then install new siding
over the step flashing. Done right, watertight.
Exactly how I'd do it if it was new construction but the existing roof
is staying. i could remove the 8 in or so of siding toward the front
of the cabin but because the addition only spans half the depth,
there's a lot more siding to remove from the rear. A profile of the
existing and new looks something like this:
// \ \
// \ \
|| | |
|| | |
You could easily use your circular saw by resting the shoe edge on the roof
sheathing of the addition and the base against the T-1-11 (if you're using a
saw with the blade mounted on the right you'd make your cut left to right,
right to left for a left mounted blade). Set the depth of cut and have at it.
This would create a cut approx. 1-1/2" above the sheathing. Cut out the narrow
strip with a sawzall. Seal the cut edge with whatever finish you have on the
siding. Step flashing material is very flexible so you should have no problem
sliding it under the siding as you apply your shingle courses up the roof.
The problem with the kerf method you mention is that it allows for a place for
water to pool. Caulking it would be fine for the short term but eventually it
WILL break loose.
An unkind remark is like a killing frost. No matter how much it warms up later,
the damage remains.
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