Smoke in Attic

[Courtney Hornsby]

I live in a townhome, however I guess it's more like a quad with four units backed up to each other making a box. I have lived in my home for almost four years and since about year one my attic has smelled of cigarette smoke which is now starting to enter my house. I know that one of my neighbors smokes like a chinmeny and I'm sure it's coming from his house. My fiance has gone up into the attic and has said it is closed off from the other units. How is this possible that his smoke is getting in my attic space? My house was built in 2000, is this up to codes?

[John Kogel]

If the neighbor is blowing smoke outside, I would guess your attic soffit ventilation is drawing the smoke in. Perforated soffit covers under the eaves draw air into the attic and vents near the ridge let air escape. If this is the case, you may need to depressurize the attic a little bit by increasing the ventilation at the ridge by adding another vent or two. This is all just a WAG. An air quality inspector could help you better by visiting the property.

[Raymond Wand]

Your unit could be depressurized while the neighbouring smokers unit is pressurized, but that fact could very (insulation/method construction, et ceteras). Since warm air rises out through the attic area, the smoke maybe brought into the unit through the common wall of adjoining units such as electrical outlets/switches. Particularly if you run your exhaust fans in kitchen/bath/laundry.

Have you tried keeping windows open slightly each level to see if that changes the occurrence of the smoke smell?

[Harry Janssen]

Having a blower door test done,may indicate were the smoke is coming from,cant hurt.

[Rick Bunzel]

I agree with the blower test. This will have the benefit of identifying any sources of air leaks / transfer between your unit and other/ exterior. If that doesn't solve the problem then the most likely source will be the eave vents. Slightly pressurizing the attic may solve that problem. That could be done by a fan the size of a bath fan. Anything larger could cause other problems.

//Rick

[Ben Tressel]

This is a very familiar problem in this part of the country. I have been involved in many inspections involving neighbors' smells leaking into neighboring units. Sometimes nothing can be addressed without opening the walls. The blower door test mentioned in an earlier post is a great idea. In addition to finding the leaks with an infrared camera or smoke pencil, you will be able to see how much the neighbor's unit is being depressurized while your unit is being tested. As far as correcting the problem goes, start by air sealing the attic. If the smell is indeed coming up through the soffit vents and making it back into your house, that tells me there is way too much connectivity between the interior and the attic. Air quality aside, this should also be addressed for energy reasons. The wall top plates, wiring and plumbing penetrations, and fixtures should be sealed from the attic side. If you have old can lights which are full of holes, consider replacing them or covering them with a fire rated, sealed and insulated enclosure. As far a the interior goes, focus on the common wall between units. Switch and receptacle gaskets help a little, and make sure any plumbing penetrations are sealed. You can also pull the baseboard and seal where the bottom plate of the wall meets the wallboard and subfloor. Good luck