Structural repairs before envelope control layers
Hi everyone. I will be having a structural engineer coming to start developing a road map for structural repairs in a 180 year old house in central MA Zone 5. There have basically never been any control layers and I’d like to protect the forthcoming structural repairs and increase durability (if nothing else) and make the house comfortable and not impossible to heat for the first time ever by implementing control layers. The roof is ~50 yo and is coming off (including overhangs) so it’s the right time to do it right and I want to do this on exterior – continuous seamless layer for water and air control.
Disregarding the roof and the south facing above grade exposed structural brick wall of the walk out basement for the time being, and only thinking about the above grade walls that are currently covered by siding – Do I need to strip off all my old siding now, way before control layer time (structural stuff has to come first) so the structural engineer can see the condition of the old sheathing under the siding (which is probably 200 year old boards with gaps etc) so he can tell me if I need structural sheathing? If I do need structural sheathing then I’ll probably get a structural WRB like Zip. If not, probably fluid or stick on. I also want to put vapor open insulation like rock wool comfort board on the outside so this old house can continue to dry more like it always has in either direction.
If i need to take off all the siding to know what’s what, but I can’t get the work done for months because it’ll take weeks to get plans and permits alone – how does that work? I appreciate any help!
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Is the interior being taken out as well?
The entire top floor below the roof will be totally ripped out and a blank slate. Most of the middle/main floor eventually will be a work site too because there’s also structural load path posts and spanned beams and stuff to do on the middle/main floor. Basement is all unfinished. - is this what you meant? Wasn’t totally sure what you mean by if the interior is being taken out too. It’s old and needs to be finished again but making the house structurally sound durable and efficient is all I care about now. Anything that’s in the way of that is fair game to be removed.
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Josh, yes, that’s kind of what I was thinking! And I can probably just put back the few courses of siding removed to check underneath till it all comes off, right? I think making the assumption based off the spot checks makes sense. Rot was what I was mostly wondering about but that can be patched if it’s random places I believe? In this case the fluid applied or self adhered wrb is what makes sense to me. Thanks for those recommendations. What’s the one for open gap cladding?
I kind of want to do this exterior wrb application before winter to help with heating the place. But it seems as though I should do all the structural stuff from bottom up before getting into that because of things shifting etc when a sill and support beams etc are being replaced.
ProClima makes a mechanically attached WRB called 'Fronta Quattro' that is for open cladding. It says it can go for 6 months before cladding.
https://foursevenfive.com/blog/fronta-quattro-the-allblack-airtight-wrb-for-modern-openjoint-rainscreens/
I'm not aware of any self adhered membranes or liquid applied that can go this long.
Delta stratus sa is a fully adhered wrb that can be left exposed for up to 6 mos
Please watch your numbers very carefully. It sounds like you have a plan to gut the interior, half the exterior, and the roof plus major structural repairs.
I have to ask if what you are not rebuilding is worth saving?
Unless you are doing much of the labor yourself I would be surprised if the numbers work on paper.
Walta
Thanks for the cautionary words from a couple folks. I am wondering about this too. The structural engineer will probably give me a lot of what I need to know about if I go through with repairs etc. I’m wondering if repairs are looking really high, if getting a new modular super efficient house design put up (maybe on the same foundation) instead might be smarter, more efficient and comfortable. And a better investment. The lot is almost an acre but the house isn’t that big. All of the old growth wood beams though, does one just throw that away?!
Regarding the existing house, The back low slope part of the roof (cape converted to full dormer sometime late 70’s which made a top floor out of an old attic) was leaking for a while and had new decking put on to stop the leaks but the top floor damage below the roof is already done and it will be coming out for about the cost of a waste container. “Finish costs” I’m not really concerned with anytime soon. I want to get it structurally good and dried in and as tight as possible. –Things that would be required for the house to remain in existence. It’s either that, demolish the whole thing or sell to someone who wants to do either of those 2 things
A complete gut and rehab of an old house like this approaches the cost of custom, new construction. While there is some romance in saving the old bones, making the new house look like the old one is definitely a labor of love and not necessarily a good investment.
That said, in answer to the OP, if the siding is coming off anyhow as a part of the plan, the more the engineer can see the better. So off it comes. But you also need to watch the schedule as well as the budget. Winter is not that far away and you want your exterior shell buttoned up before Christmas. Before Turkey Day would be better, as it leaves a little leeway for delays. Once we get well into December, exterior work gets pretty tough in central MA.
Is the house timber frame? You have a great opportunity to expose the timbers, the floor joists, old flooring, etc. If you find that's not your style and you choose to start all over, there are companies that disassemble old timber frame houses and barns and resell them for big money.