by Scott Gibson
I know youíve heard it beforeóa deck being built
without flashingóbut this time the home is a log cabin. Iíve already discovered
some punky wood and thatís not even under the ledger, just in the adjacent area.
Whatís involved when a log has rotted? Since each log is structural, it looks
like itís going to be a nightmare to replace any of them. Is there a way to
replace just some of a log?
Log cabins are obviously very different than stick-framed houses, but the
same cautions about water intrusion still apply.
Improperly attached deck ledgers for decks will lead to rot.
Once youíre stuck with the problem, the best solution may be to call an
expert. Restoring a log house is not exactly a beginnerís project.
I called Peter Caron, an Edmonton, Canada, expert who specializes in log
buildings. Almost all of his work is on historic buildings, some of them dating
to the18th century.
In short, you may be able to replace part of a log. But much depends on the
extent of deterioration and where itís located. And thatís not easy to assess
without a site visit.
How to start
Start by taking core samples
Caronís first step would be to drill a series of holes in the suspect log to
find out how deep the rot goes.
Up to one-half the thickness of a log can be refaced (not as much in areas
where structural loads are great).
Caron removes all rotten wood and adds a preservative treatment, such as
boron rods for the sound wood thatís left. A new face can then be attached with
stainless steel screws or bolts. Fastener heads can be concealed by
counter-boring the new piece and inserting wood plugs.
Caron avoids epoxy if he can because he thinks the repair tends to trap
moisture and lead to more rot in the future.
If this all sounds painless, think again. ďItís easier said than done,Ē says
Caron, ďbut itís doable.Ē
Replacing all or part of a log
If repairs are more extensive, the next step up in complexity would be to
leave the ends of a log in place and splice a new piece in the middle.
In this case, Caron through-bolts 2x4s on both sides of the wall to stabilize
it and keep logs aligned.
Whole-log replacement may require jacking part of the wall up to make room
for a new piece. Caron inserts 1/2-in. steel plate between logs and places
hydraulic jacks on both sides of the wall at each plate to do the lifting.
Jobs are made more difficult by interior finish that may have to be removed
and by doors and windows, whose operation might be affected by the repairs.
Keep deck ledgers away from the building
Then thereís the old deck ledger problem.
In a stick-framed house, the wall can be protected by flashing thatís tucked
behind the siding and bent over the top edge of the ledger. Water sheeting off
the wall is directed away from the building.
It gets a little tougher with a log house.
Which leads to Caronís suggestion that the deck not be attached to the wall
in the first place. By making the deck free standing, thereís no way for water
to be trapped against the wall of the house.
If attach you must, you flash the intersection by cutting a horizontal saw
kerf into the log above the ledger, inserting the top edge of the flashing into
the kerf and sealing the seam with caulk.
But log houses move around a lot, and the caulk may fail in time. This isnít
a technique that Caron would favor.
ďWater in, water out,Ē says Caron. ďThatís the key.Ē
Scott Gibson is the former editor of Fine Woodworking
magazine, and a former editor at Today's Homeowner and Fine Homebuilding
magazines. He is an avid and accomplished woodworker and carpenter.