I am working on a c. 1850 house in Vermont that has not been updated. It has clapboard siding directly on studs (no sheathing) and plaster on lath. I’m reluctant to remove the siding or the plaster since both are original and in good condition. By not removing either, I have made it impossible to install an air gap prior to insulating.
I am considering building a stud wall on the interior of the house which would conceal the plaster but allow the installation of insulation. My questions are:
1) does anyone else have a better solution given these parameters,
2) do I need an airgap between the plaster and the new wall, and
3) am I just making more work than necessary?
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If you can keep o/s air from infiltrating into stud bays (ie caulk/paint) I wouldn't worry so much about walls and would concentrate on ceiling and floors. All be it was Socal I grew up in a house with no insulation in walls just cedar shingles (painted) and lath and plaster on inside. The house stayed remarkably warm in winter and cool in summer.
I’ve run into this on a house from a similar era. You have to pick either interior or exterior to demo.
If you demo the interior you can cut strips of zip sheathing and fit it between each stud bay and install it with an air gap behind the siding. Then insulate with whatever your preference is. This is a lot of work. Bonuses are it’s easy to run new electrical and you could fir each stud out to get 2x6 walls.
Otherwise tear off the siding, run electrical and insulate from the outside, sheath and reinstall siding with furring strips for an air gap.
Both are costly but will greatly improve the house’s comfort and performance. The choice really comes down to which is in better condition and who you can find. For example you may have really nice trim that you wouldn’t want to rip out or the house was recently resided.
Whatever you do don’t be tempted to chalk the underside of each clapboard. That is not a good solution to deal with air sealing.
Good luck
Considering the unique situation with the original materials and your goal of insulating, here are some suggestions:
Interior Stud Wall:
Building an interior stud wall can be a viable solution. This way, you can preserve both the siding and plaster while still achieving insulation. It's a practical compromise.
Air Gap:
Ideally, having an air gap between the plaster and the new wall could be beneficial for moisture control and allowing any potential moisture to evaporate. However, this may not be absolutely necessary if the space is well-ventilated.
Insulation Material:
Choose insulation material carefully. Consider using a material that provides good insulation while allowing some breathability to prevent moisture buildup.
Vapor Barrier:
Depending on your climate, consider a vapor barrier. In colder climates, it helps prevent moisture from moving into the wall cavity, potentially causing issues.
Professional Advice:
Given the age of the house and its unique construction, it may be wise to consult with a preservation architect or a professional experienced in historic buildings. They can provide specific recommendations tailored to your situation.
Local Building Codes:
Always ensure that any alterations comply with local building codes and historic preservation guidelines, if applicable.
Cost-Benefit Analysis:
Weigh the benefits of insulation against the potential loss of original features. Sometimes, preserving the historic integrity of a structure outweighs the energy efficiency gained from insulation.
Remember, each historic building is unique, and solutions should be tailored to its specific conditions. Consulting with experts who specialize in historic preservation can provide valuable insights and ensure that any alterations are made in a way that respects the building's heritage.
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You did not mention windows and doors. Are they original? If so, you will need some sort of secondary system to help with energy conservation, which may have bearing on your decision on insulation.
Hi everyone,
I am a preservation architect. That's one of the reasons I took on this challenge. What I'm proposing makes my preservationist self cringe a little bit but this structure will be used as a modern residence not a public building or a museum. Some sacrifices can be made. It seems like building a secondary wall and moving the original trim to the new wall is the least damaging sacrifice than removing original plaster or original clapboard which are in good condition.
That is actually the basis of the question: has anyone encounter this situation and figured out a clever way of doing this without sacrifices? If I am going to find someone who has managed to do that, this forum seems like the place to find them.
Also the question of condensation if I do build this wall - is the stud cavity enough of an air gap or do I need another between the plaster and the new wall?
The windows are original, I plan to make operable interior storms.
I would rather not go without insulation all together as I too grew up in an uninsulated 19th century farmhouse (in the mid-Atlantic not Vermont) and I remember wearing many layer and still being cold. One of my goals as a preservation architect is to help show people that existing buildings can be energy efficient so people stop insisting new is better. "The greenest building is one that is already built." Carl Elefante
Kate
If you’re talking all the trim off, why not demo the plaster, put in an air gap, fir out the walls to 2x6, hang blue board and do a plaster finish? Then you have the best of everything- air sealing, air gap, extra insulation, and plaster walls. I don’t understand building a new wall in front of the plaster to save it. It will never be seen, window jamb extensions will be super deep and the house will still be poorly insulated with tons of air infiltration. Perhaps this is a compromise between preservation and achieving modern efficiency standards so the house preforms well for years to come.
I saw an article about this a while back here’s a link
https://www.greenbuildingadvisor.com/article/insulating-walls-from-the-interior
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