The clothespins do nothing!

December 9, 2007 9:57 AM

Smelly house filter. Smell similar to stale cigarette smoke coming from our attic, and getting worse. What is it? How do I stop it?

The smell started three weeks ago. It was minor at that time and was obviously coming from the attic. It has since strengthened until it now permeates the house. It is strongest in the attic, but I can't find the source. No dead animals as far as I can tell.

As soon as you come in the front door it hits you. We bought a fresh Christmas tree yesterday, but can't make out its aroma over the attic smell.

The attic has nothing organic in it. Some books and magazines, christmas decorations, odds and ends. Everything is in brown cardboard boxes or in plastic tubs. It's not crowded up there, it's relatively empty. We haven't put anything new up there in several months.

It has a sloped roof with insulation pads between the joists in the ceiling. One of the lengths of insulation fell to the floor about two months ago, but the smell didn't start till a few weeks later.

There are two small (12" x 12") skylights in the roof.

We've had a dead mouse before - this is not the same. This is strong but nowhere near as gross as the smell of a mouse, or bad cheese, or rotten eggs, say. The closest we can come to describing it is stale cigarette smoke.

There is zero chance that anyone is smoking up there, and anyway the smell is not quite a cigarette smell.

As far as I know, the roof was re-shingled last sometime around 1997. When I move the insulation in the ceiling around, a lot of old wood and shingle bits fall to the floor. The house is about 60 years old. We recently installed a new furnace in the basement, but there are no heating elements or pipes in the attic.

It's getting stronger all the time. Baking soda and vinegar are not absorbing it. Help!

posted by lockedroomguy to home & garden (14 comments total)

As far as I know, and if it's a newer home, the insulation should be on the floor of the attic not lining the roof. This is so that air can circulate in the attic and keep moisture from building up under the roof and rotting it from inside. You may have some type of mold under your insulation that is causing some type of smell when the roof gets hot in the daylight. I'd pull all of the insulation down and lay it on the attic floor and see if that changes anything.
posted by kuujjuarapik at 10:07 AM on December 9, 2007

Sounds like mould.
posted by fire&wings at 10:14 AM on December 9, 2007

We had a similar smell once, and it was a frayed wire touching our insulation. It smoldered for weeks and could have burned our house down had we not found the source.
posted by peep at 10:32 AM on December 9, 2007

Do you have a chimney that needs cleaning?

The attic has nothing organic in it.

The cardboard boxes and the wood of the roof are both places to look for something rotting, or for signs of mold. The fact that insulation and bits of wood are dropping off or rotting is an indicator that you may have a dampness problem somewhere....a leaky skylight maybe. If it's possible, get an attic fan to blow air out of one of your skylights to get rid of the smell. Investigate further for frayed wires or dampness up there, or call someone in to check it out. I smelled the exact same smell for months in my house whenever I was in my living room (stale cigarette smell is an excellent description) and it turned out that the tub in the bathroom above the living room had a tiny leak and some of the joists between the levels of the house were damp and just starting to rot.
posted by iconomy at 11:10 AM on December 9, 2007

My parents had this problem in their near-century-old house; an acrid smell much like you describe. The problem was bats nesting in between the interior and exterior walls. When the sun hits the wall, it heats up the guano and such which makes the smell stronger.

Do you notice it more at a particular time of day, or have you noticed any brown stains on your siding?
posted by eiramazile at 11:13 AM on December 9, 2007

Kuujjuarapik, for what it's worth it's not a newer home, and we also have blown-in insulation on the floor of the attic.

Eiramzile, It doesn't seem to be different at different times of the day. No brown stains. We've heard that there are bats in the neighborhood, but in 5 years we've never seen or heard one, or met anyone else that's seen or heard one.

So far we have suggestions of mould, a live wire touching insulation, batshit, and rotting wood. I'm going to go check for batshit, and the live wire now.

Any other suggestions, particularly along the lines of what to do next?
posted by lockedroomguy at 1:51 PM on December 9, 2007

Another idea: When an old roof is stripped, lots of debris rains into the attic. The debris is often split up old cedar shake and asphalt shingles. This stuff can have an old, dry, musty wood smell to it. If your roof was recently redone and the insulation was covering the roof, all of that debris would still be up there. If a panel fell in and the smell started, your problem could be the smelly debris. If your attic floor is insulated anyway, the insulation on the roof is only going to cause long term problems. I'd pull it down and throw it out, along with any roofing debris.
If it's the roofing debris that smells, that is.
posted by kuujjuarapik at 2:59 PM on December 9, 2007

Kuujjuarapik, thanks for the follow-up. When they did our roof - before we bought the house, they just let all that crap from the old roof fall into the insulation, so it's certainly all up there. When we pull down the insulation it comes pouring out.

But it's been there for at least ten years, and the smell just started in a minor way a few weeks ago, and now has grown very strong in the last week or so, so I'm inclined to think it's not that old wood. The problem is that the smell is in everything so I can't locate the source.
posted by lockedroomguy at 3:34 PM on December 9, 2007

Kuujjuarapik - I meant to add, we are still going to pull down all the insulation for good regardless of whether is has anything to do with the smell. Thanks for that.

Any other ideas still welcome, as I still can't narrow down the source of the smell? We're up in the attic right now pulling it apart.
posted by lockedroomguy at 3:38 PM on December 9, 2007

If it's throughout the house I don't think I'd rule out the furnace. What kind is it, and how recently was it installed?
posted by sgass at 4:25 AM on December 10, 2007

The furnace is a Buderus G215, and it was installed about 8 weeks ago. It's actually a boiler, providing heat via circulation hot water. So it's not a forced air furnace. The smell is most minimal in the basement.

Yesterday we found that where the chimney meets the floor of the attic, there was a little bit of moisture. Not enought to be called drops, but enough that part of the ball of your finger feels wet after touching it. It did rain quite a lot yesterday.
posted by lockedroomguy at 7:32 AM on December 10, 2007

Any idea when the chimney was last cleaned/inspected? Do you have a fireplace or woodstove, or just the furnace? If the moisture is close to the floor rather than at the roofline it could be a sign of deterioration, as opposed to bad flashing where the chimney goes through the roof.
posted by sgass at 3:58 PM on December 10, 2007

Sgass.

Just the furnace. So if it is a sign of deterioration does that mean something about the smell?

All,

We've narrowed down the source of the smell. In the second floor bedroom closed there is a hole in the wall. Through this hole you can see the exterior of the bricks of the chimney. The smell is definitely coming from this hole. May or may not be coming from the chimney, but it's definitely coming from the hole.

We had the furnace guy in, and he tested the chimney's ability to draft air upward, and he said it was fantastic, with no leaks. He said even if there was something smelly in the chimney, and there was a leak in the chimney, we wouldn't smell anything because the updraft is so good that the smell would go straight up out of the house.

He also said "That is no smell that ever came out of a furnace." He thinks it's a dead animal between the chimney and the wall. As I said in the op we've had dead mice before and they smelled NOTHING like this.

Currently we've opened the windows in that bedroom and closed the bedroom door. That room still smells but the rest of the house is clear. We're going to wait a few weeks and see if the smell dissipates, which would prove the animal theory, probably. If it doesn't I'll probably repost about how to burn down a house, or how to tear off my own head and eat it, or something.

Other suggestions still welcome!
posted by lockedroomguy at 7:02 AM on December 21, 2007

So if it is a sign of deterioration does that mean something about the smell?

It could, especially if the chimney isn't lined. I'm certainly no chimney expert, but if you're seeing moisture in a place like you described it's possible that it's seeping through the brick, carrying with it the smells of whatever combustion byproducts are lurking inside. Could be mold as well, I guess. In any event it sure doesn't sound like a dead animal to me -- in my experience smells like that don't last this long, unless maybe it's a raccoon or a groundhog.

If the smell isn't gone soon I'd look for someone with some expertise in masonry chimney construction (ie a chimney sweep or mason) and have them inspect it. The fact that there was a good draft when the furnace guy checked it might not mean a whole lot.
posted by sgass at 6:27 PM on December 27, 2007