Prioritizing Renovations to an Old Cape House
We bought a 1930 Cape, not knowing the difficulties ahead…Climate zone 4 on Long Island so salt air is also a part of life.
We moved in to the second floor last year, planning to renovate the first floor, which the previous owner had turned into a maze of rooms. I’ve now read PGH and growing to think at best we may end of up with a Sort of Good Reno….primarily because of budget constraints. Ideally I know the whole envelope would come first but I doubt it’s affordable at this point. So hoping we can do work in stages.
It was the end of summer when we moved in and the upstairs was unbearably hot. I know it needs insulation and I’m thinking as a phase one as a start to have the attic floor well insulated, and the knee walls. Does that make sense as a start for up there? I’m saying phase one because in the next year or so we’d like to install solar panels and I’m thinking that would be a time to replace the roof as well. There is no roof deck, nor rafter insulation–the old cedar shingles have been covered over with three layers of shingles. And there are no soffit vents, and not enough overhang to put them in. One side of the second floor knee walls has open attic space so perhaps we could insulate those knee walls.
I’m also thinking of having the exterior walls insulated with dense pack cellulose as part of phase one, and hopefully the basement rafters. My doubt here is I’m assuming before any insulation is done on the exterior walls, I need to verify that there’s sheathing on those walls. At some point in the near future, we will need to replace the cedar shake siding, but it’s just not in the budget for now.
I’ve tried searching for passive house professionals on the professional organization website, and even basic google searching. Only found a couple and they were homes built by architects that had building companies–located in NYC so there’s no point in contacting them because of cost and distance from us. The search term that worked–in case it helps others–was energy modelling. I found one company–Green Team LI–that hopefully does true modelling. I’m having an energy audit done by them tomorrow and will have a better sense of how science based they are, and what ideas they have to tackle the house. We’re meeting with GC this week also for the interior work, so perhaps will be surprised if they have something to contribute to these concerns.
We’re still planning to get a heat pump, even though if I understand PGH correctly, we’re going to have potential issues sizing it without the house being as sealed as it will be in the next couple of years. We currently have a oil run boiler and the chimney is sited in a way that makes the first floor layout difficult, which is why we were thinking of the heat pump. I’m hoping that’s not a mistake.
I have some understanding of ducted versus ductless mini splits. Where I’m a little confused its about efficiency and maintenance. In PGH there were a couple of instances where the comment was made that in hindsight ducted wold have been better. I’m thinking with out potential new floor plan we can site ducts on interior walls. I was assuming ductless was more efficient only if ducts were on exterior walls which would make the ducts less efficient. But i’m unclear.
Apologies if I’m all over the place. Just a homeowner trying to do what is possible to make this at least a Sort of Good House. The book was great to read btw, but a bit overwhelming…the number of considerations. I’m feeling we live in a bit of a building science desert, otherwise I’d have some comfort knowing I had knowledgeable professionals. (We met with around 7 roofers last year as I was trying to see about the possibility of soffit vents…literally only one knew what convection was.)
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Depends on what you are trying to accomplish, prioritize what you really need the details can wait. It will take a long time to recoup those energy savings from materials and insulation. I would start with changing your heating system. A good HVAC professional will be able to size it correctly even if you never add all that extra insulation. Get some fans and a portable ac if upstairs doesn’t get complete by next summer
Thank you so much. I’ll see what happens with the energy audit today, and see if any insulation at this point makes sense.
Then I think we need to talk with a few HVAC companies to hear the options.
Carina,
You might want to read this article: "Insulating a Cape Cod House."
Thanks, Martin. I had to register for prime and then had to call customer service because it didn’t update me🥲
I read the article. I had come here last year via Fine Hone Building when I was researching the insulating of Cape attics, and I remember from PGH the point of the attic being conditioned. Because I’m thinking to get solar panels hopefully in a year, and then would want to replace the roof, I suppose it might make sense to forget insulating anything in the attic for now..Then see whether we can afford to extend the roof to add soffit vents and afford to seal the roof from outside.
I was just worried that without good enough insulation the ASHP wouldn’t be sized correctly. But we had our audit today. Maybe I’ll know more when I get the results.
I think as a non professional in the building field, and not being rich, and not having found a contractor who knows this stuff, I’m probably hoping for too much. Trying to be green is making me blue…
The first question is how long will you own this house? Most people today move before year 7.
Nothing you asked about will recover its costs in 7 years and none of it will add a penny to the resale price.
The one thing likely to recover its costs was total absent from your list that is air sealing. Make sure your energy audit included a blower door test with an ACH50 calculation and inferred photography if not cancel and find one that does. Often on leaky homes they conveniently fail to do the ACH50 calculation because they do not want you to understand on a windy day the air in your home is being exchanged with the outdoor air 15 or more time per hour.
I generally despise spray foam insulation and conditioned attics but it is your only real hope to make a 1 and a half story building like yours to be anything but drafty. My wild guess is and untouched cape will have 15-20 ACH50 number and with spray foam you might get under 5 ACH50.
Note installing insulation before air sealing is foolish and insulation can not do its job when all the air is escaping thru the leaks bypassing the insulation and if you come back later to air seal all your new insulation is in your way and must be removed.
Dense packing the walls is likely not possible dew to the lack of a water-resistant barrier in your walls and you cannot allow the cellulose to get wet.
Generally insulating basement “rafters” is a poor option it is better to insulate the exterior walls with more spray foam and make the basement part of the conditions space.
New construction passive houses in general fail to make economic sense and passive house retrofits are economic suicide.
https://www.greenbuildingadvisor.com/question/devils-triangle-
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updatehttps://www.greenbuildingadvisor.com/article/insulating-a-cape-cod-house
Walta
Ooof ok. I didn’t see this till after the audit. I had asked about infrared but they said it would be pointless right now because the difference in inside and outside temp isn’t enough. It wasn’t windy today so hopefully the numbers we get will be useful.
And how long we will be here? Can’t say but was thinking at a minimum ten years—longer depending on health.
If we could afford it I would have done phase one with air sealing—but tackling outsulation and siding seems like it’s outside the budget. I had thought perhaps we’d do it when budget allows. It’s also the problem of the roof—the air sealing I mean. No soffit vents as well. The roof alone will be an expensive project.
All these concerns came from wanting to do even a small part to reduce carbon etc. But I hear strongly you saying retrofit is economic suicide…
I know this audit is going to include a strong pitch to insulate everything. You answered a big doubt of mine about the cellulose and the exterior walls. I see it makes no sense at this point.
Make sure the Auditor does a blower door test; fixing air leaks will help with comfort far more than adding insulation. A leaky house is an uncomfortable house. One of the great properties of dense packed cellulose is that it dries out. But lack of an interior plastic barrier is a plus, as it can dry to the interior. Great product! Of course you should make sure than nothing inside the walls gets wet, and do not put vapor barriers on both the inside and the outside; thats a great way to start a mold farm with any insulation.
I should add that one hugely important point is insulate and air seal your cellar! That's a sore spot in most houses and most people ignore it. Do not put batt insulation against concrete (it's damp) , but EPS or Styrofoam or polyiso work fine.
Thanks! Yeah, the basement has no insulation at all. I guess I’ll find out what the options are…
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