Cedar Clapboard Sidewall/roofing Tie In

remoguy

I keep running into cedar clapboard houses where the angle cut clapboard on a sidewall rests right on the roofing. I think this is wrong as it allows moisture to wick up into the end grain of the siding and eventually rot. I have had to hand cut back rotted board ends on entire slops and r&r other boards. The house I am working on now has a second layer of shingles recently applied and the roofers just butted the new shingles up to the clapboards and put some type of black compound at the "joint" which has now pulled away from the shingles or the clapboard. What would have been the correct way to apply the second layer of shingles here? Should I just add more roofing compound to fill in the gap or should I cut back the clapboards and let the old step flashing on the original roof do its job?

GHCJustin

we always cut wood siding 3/4 of an inch off the roof shingles for the reason of the water wicking into the siding..also we cut the shingles approx 1/2-3/4 of an inch away from the step flashing because this allows the water to run down and wash out any debris that collect in the corner and also because ive seen so many roof shingles cut tight to the step flashing and over time they end up bunching and are way too tight... As far as your problem you could either cut the siding back like you said or cut the roof shingles back a bit.. i wouldnt fill the gap between the siding and shingles because it wont hold and it will break free again and also you want the water to be able to get back out if it gets under the sealant instead of being trapped beneath it...

Grumpy

It is wrong for the carpenter to butt the siding directly to the roofing. Usually we only see this when there are multiple layers of roofing, and since we are tearing it off... it's not a problem.

However from time to time we do see it, and yes it is a problem when it happens. Usually when we are tearing off the roof some of the siding boards will go with it, especially if some A-hole doped the wall with roof cement. Carpentry is always an extra. problem solved!

Tear off the roof and do it right! Another reason why roofs should always be torn off.

WNYcarpenter

The way I believe it should be done is to cut the clapboards with a skill saw 4 1/2" or so off the roof and add a 5/4"x3 1/2" trim board that runs 1" off the shingles the length of the roof. Add your step flashing, and counter flashing (if desired) before you apply the trim. Also make sure you prime or seal all the end grains of the clapboards whether you use a trim board or not.

We've also found that fiber cement will wick moisture as well if applied by the method described be the OP.

oldfrt

Another problem with some carpenters on new construction is they will put clapboards over the bottom piece of flashing,where a gable wall abuts an intersecting wall allowing the water at the bottom the run to drip behind the siding.Watch this area.Make sure that first piece of flashing directs any run off over the front of the siding.
I've seen a lot of damage from one little mistake!