LP Siding Questions (Mostly T1-11)

Old 07-09-23, 01:34 PM
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LP Siding Questions (Mostly T1-11)

Daughter bought a house recently. Ranch built in 1990 located in PNW. 1300 sq feet plus garage. We are doing work on the house and she plans on flipping it in a couple of years. LP siding. Lapped on front and one side of garage, T1-11 everywhere else (installed vertically). 5/8" T1-11. I'm hoping to avoid cutting a bunch of siding back until we have a siding game plan but from what I can tell (looking through penetrations available etc.), the conditioned part of the house has kraft faced insulation in the stud bays and there is foam board installed on the exterior of the framing (foil seal on both sides) with no additional house wrap. I don't know how thick the foam board is but the T1-11 and foam board are attached using 2 3/8" nails so can't be too thick and I've confirmed the foam board is on the outside of the framing (v. inside stud bays). The unconditioned parts of the house (attic gables, garage) are a variety of siding techniques. One side of the garage with the lapped siding has felt paper and Simpson RCWBs for let-in bracing. Front side of the garage has OSB sheathing for structure underneath the lap siding (unsure on house wrap). The other side of the garage and the gables are T1-11 attached directly to the framing with no house wrap. 16" OC framing. Questions:

- Since I'm trying to avoid knocking out a bunch of drywall on the conditioned parts of the house, my assumption is the T1-11 is providing wall structure (installed vertically) and thus no let-in bracing. Safe assumption or do I need to start ripping some more stuff apart?
- I haven't ripped off enough siding to see any manufacturer markings on the foam board. Is there a potential the foam board is structural? Given it's nature and the length of the nail mentioned above, I can't imagine it is but...
- Can foam board function as house wrap?
- I've attached pics of things and one of those is where the bottom run of vertically installed T1-11 is overlapped with the top run where the first floor meets the attic gables. What I'm stymied by is how they made this work with the foam board under the bottom run but not the top. Is this fairly common back in this time frame?
- I've attached a pick of the long side of the house including the side of the garage that has no foam board (the rear of the house is the conditioned portion). I can't see how they transitioned the T1-11 from straight to stud application to application over foam board. Just a trick of the eye?
- On that long side, they overlap the top and bottom runs and then there is some type of metal channel that runs the entire length and there is an additional third piece of T1-11 that is fairly short at the very bottom. It doesn't not look like Z flashing but it appears they were using ~9' T1-11 sheets and they needed a small piece on the bottom to cover and this is effectively a connector strip. I'm also guessing they didn't use this to join the bottom and top (gable) sheets because they had to compensate for the foam board thickness and thus overlapped. Am I warm?

The siding is failing in places (mostly near the ground and mostly the T1-11) and all (or parts) need to be replaced. So far from what I've seen, the rim boards and studs are in good shape One of the sides pictured is way worst than the rest and my guess is they had firewood stacked over there. Initially my daughter wanted to rip it all off and install lapped Hardiplank. Assuming I'm correct on the T1-11 being structural, that would mean sheathing and that's going to add time/cost. Could go Hardipanel as an alternative since that's structural . I'm trying to convince her to put a skirt board at the bottom with some flashing (top and bottom) and a belly band where the first floor and attic meet (flashed). Then replace The T-1-11 as needed (again, basically at the bottom) and a few of the lapped siding boards that need some love. Assuming we go the latter route, am I just asking for trouble with the LP that is good (at least for now) and won't be replaced. Will likely call out some siders but at a minimum want to be an informed consumer. Any other suggestions appreciated and thanks in advance.


Last edited by Redmond123; 07-09-23 at 02:06 PM. Reason: Forgot pics...

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