Image Credit: Gregg Zuman
More Q&A Spotlight
Gregg Zuman’s house in Beacon, New York, was built near the start of the Civil War, and like most any building of that era it’s in need of a few repairs. At the moment, Zuman is stuck on what to do about the clapboard siding.
“It’s slathered with lead paint, of course,” Zuman writes in a Q&A post. “The issue is how to move ahead: figure out a way to remove the lead paint and apply a coat of 50-50 pine tar-raw linseed or cut losses, remove the old clapboard, replace with cedar clapboard, and apply 50-50 pine tar-raw linseed or suck it up, paint over the lead paint with decent lead-free paint, and embrace compromise.”
The cheapest option probably will be painting over the lead paint, but Zuman worries that would make the wall a vapor impermeable barrier — something he wants to avoid at all costs.
The house is balloon framed, with no space between the framing and the siding — meaning no sheathing. Zuman plans on using Airkrete insulation, and his overall objective is to “honor the history of the structure while updating the materials were needed with products free of fossil fuels.”
How does he proceed? That’s the issue for this Q&A Spotlight.
This wall needs a rainscreen
Lead is an obvious concern, says GBA senior editor Martin Holladay, and any prep work on the clapboards will need the help of a contractor who understands and follows lead-safe procedures. Even if the lead problem can be solved, however, Zuman will have a wall without an effective air barrier.
“If you leave the existing clapboard in place, you’ll have a wall without a rainscreen and without a decent exterior air barrier,” he says. “(Airkrete has a tendency to shrink…
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11 Comments
Strip with poly tubing and soy
If the project presumes creating an air-barrier, you presume removing the siding. If you are removing the siding, you're halfway to salvaging the siding by removing the paint efficiently. Here's how. Buy heavy duty poly tubing. You can get it from a big office/warehouse product catalog. Poly tubing is for bagging up posters or rolled drawings but works great for lengths of millwork. It comes on rolls of varying widths, so get a dimension that fits the width of the clapboards. You unspool whatever length you need to fit the length of a clapboard. Remove the clapboards intact and remove nails. Bag each piece. Fill each bag with a paint remover of your choice. I prefer a soy based product. Follow directions for dwell time. Use a firm grip to remove the millwork from the bag while containing the waste in the bag (watch for splinters); discard the bag. Scrape any wet remnants. While still damp, soy remover can be rubbed out to bare wood with cloth rags much better than finishing with metal scrapers. Repeat the process on stubborn clapboards if necessary. Rinse to deactivate stripper. Install/finish.
A convenience of the bagging method is that you can set the bags aside to let the stripper do the work rather than use labor time. Of course all phases of work have to be lead-safe work practice, but if you can set up a big area for hand scraping the easy bits, that could improve the efficiency of the bagged stripper.
Another paint option
Greg (in case you are still following this discussion),
You might want to consider potassium silicate paint. It is very vapor open and sticks tenaciously to most materials (except old chalky layers). It might be worthwhile for you to buy a sample, do a test section, ans see how it stands up over the winter.
Pine tar
I didn't see anyone in the original Q&A address the pine tar/linseed oil plan. I've used it here in Maine and think it's a great product. I'm happy to pull together some pictures if that would be helpful (rough pine board siding with black pine tar applied). The application is about three years old at this point, aging well.
It's pretty odorous, smoky but not 'bad' smelling. It goes away pretty quick, but you'll get a little bit of odor when it rains for about six months - again, just a smoky smell.
Re: Pine Tar paint
Sam,
I would be interested in seeing your photos.
Exterior insulation over the clapboard
I went through the same exercise with my old home in Toronto. I left the siding and installed two continuous layers of eps insulation. The first layer against the old siding was foil faced so that I could tape the seams and have my continuous air barrier. An additional advantage with this system is that I had foil facing up against the old siding , providing me with a radiant barrier.
Exterior insulation over the clapboard
Grant,
I'm interested in how you did this. Do you have pics?
Bill G
[email protected]
AirKrete and airtightness
Just a bit of follow up on this: I emailed the tech lead for AirKrete asking why there is no information on their website about air tightness performance of AirKrete--no response.
The data loggers of the NE Massachusetts meeting house cavity-insulated with AirKrete are not telling us anything yet about hygrothermal performance of the AirKrete but I will be following up on this in the coming months, and hopefully also get a chance to do some IR camera work there to see if we can evaluate sustained air leakage performance of the AirKrete cavity insulation.
old siding/ lead paint
If there is room inside the building, add an interior wall starting from the exterior side with a WRB such as Typar, then taped plywood sheathing, then 2x4 or 2x6 frame with wiring in it and fill with dense pack cellulose, Membrain vapour barrier and drywall. The ballon frame continues to vent the siding like it has for + 150 years..The new wall is close to airtight, but vapour permeable, and the heating bill will be reasonable. Overcoat the lead paint with an appropriate product. .
Ballon construction
My concern goes beyond the lead paint. For that I would reside with cedar. I am fond of old houses and grew up in one. That house was not balloon framed but was stone - 48" thick at the basement tapering to 24" at the second floor. Talk about thermal mass!
My greatest concern is balloon construction. As I understand balloon construction, the vertical structural members extend from the sill plate on the foundation all the ay to the roof - no fire stops. Five of my school friends were killed in a fire in a house built that way. Without the fire blocks and wood lathe/ plaster walls you have a natural chimney with nice dry wood on both sides! Our house did not use balloon construction because of the stone. Floor joists were a true 2x10 chestnut. And we tested the walls by drilling holes in the wall and dropping a fishing weight down on a string. So I would strip the siding, add fire stops, fill with mineral wool insulation, sheathe with plywood and reside with cedar boards or (my preference) cedar shingles.
BTW have you had the inside of the house checked for lead and asbestos? And has the electrical system been checked? In the house I grew up in, we had gas lights and these were disabled at the source, removed with the pipes left in the walls and plaster patched. The knob and pole wiring was replaced with flexible metal conduit. I do not remember whether it was grounded or not.
I also built a house in CT with cedar siding and used a bleaching oil for a finish for a nice cape cod look. It has since been banned.
Thank you!
Gosh - I didn't realize a whole repackaging of this thread was part of it being featured in the newsletter! I just stumbled over this new thread now. Super useful, as I'm still in the final stages of making decisions and moving ahead. Lots more to process - this new input is invaluable. I plan to follow up soon with new info for everyone. Cheers.
Response to Gregg Zuman
Gregg,
Glad to know that this article is helpful. Please post an update here when you decide what to do.
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