Q. I have a vestibule that I had painted maybe 15 years ago. Now the paint is chipping away on the outside wall, but not on any of the interior walls not exposed to the outside. The painter said it was calcimine, as the surface is lath and plaster. He recommended applying a skimcoat or an oil-base primer and a layer of plaster, which would add about ¼ inch. This concerns me as there is mahogany door trim and wainscot, and I don’t want to encroach too much on them. Do you think these are good suggestions, and, if so, which one would you choose? I also wonder about the advisability of prepping it really well and painting it, knowing that it may last as long as the existing one did.
A. I checked in with a painter friend of mine Mark O’Lalor. If it is a calcimine plaster issue, O’Lalor said, then the bond between the plaster and the old paint job will probably continue to fail. Under these circumstances, he has had the best luck scraping all of the compromised surfaces and applying an oil-based primer specifically designed for calcimine volatility. Once coated with Benjamin Moore’sSuper Spec Alkyd Calcimine Recoater, you can replaster and repaint without damaging your architectural details.
Q. The stain finish is peeling on my house, a two-story Colonial. It was applied five years ago. The problem is only on the lower half of the east side of the house, which gets the most sun exposure; the rest of the house is shaded by trees. The stain that was applied is of premium quality. I don’t see this problem at any of my neighbor’s houses. Can you identify the cause, and if so, what can I do to solve it?
PAUL M., Acton
A. There are two things to consider:
1. Could a window sill, flashing, or roof runoff problem be causing the damage, allowing water to get behind the siding in this area?
2. Was this siding replaced but not prepped properly prior to finishing?
Painting over bare clapboards often causes problems when the siding is not etched of mill glaze or is dirty. Using preprimed clapboards is a better approach.
Readers reached out after article on a odd smell (“Hunting down cause of mysterious septic smell,’’ Oct. 22) ...
From Anne & Martin: We did renovations that including a bedroom addition and connection to the sewer from a septic system. We started getting a strong odor of sewer gas and immediately suspected the sewer hookup was the culprit. The plumber checked and found no problems. I went onto the roof to check the vents and discovered that the carpenters had stuffed a rag into the soil vent pipe. I removed the rag. Problem solved. They didn’t like the smell, and had mistakenly left the rag there after finishing the framing and roof.
Amy Holland in Andover: I had a similar problem. The electrician thought it might be coming through the PVC pipe that housed the electric that runs from the septic tank to the house/basement. He said it should have been sealed at the tank. He sealed the end in the house with silicone, and the smell has been gone ever since. Just a thought ...
From E & J: We had the very same problem when we moved into a rental house with the washer and dryer in the basement. Every time we used the washer, a septic odor would permeate the entire house. The real estate agent finally had a plumber come out. It was determined that the drain pipe from the washer was not wide enough and that the elbow joint in the pipe was too close to the washer, thus causing waste to back up into the pipe. They changed the pipe and moved the elbow farther away — no more septic odor.
Rob Robillard is a general contractor, carpenter, editor of AConcordCarpenter.com, and principal of a carpentry and renovation business. Send your questions to email@example.com or tweet them to @robertrobillard. Subscribe to our free newsletter at pages.email.bostonglobe.com/AddressSignUp.