What causes "old smell" in a clean but older house?

Question

Older homes in warmer climates seem to have a somewhat common smell to them, even after cleaning them. Does someone with experience renovating such homes know what tends to be the cause of these odors?

I am not talking about smells from plumbing, the kitchen or even pets, but the smell that you can sometimes find in wooden sheds, back-country cabins or generally homes built in the 60s and 70s. Sometimes it reminds me of rodents, but only faintly.

I am about to do some renovations, and thought that if this is something that can be included, it would be worth it. For example if this was caused by wood or insulation that somehow got wet in the walls, we could clean out that wall cavity as part of a gut renovation...

How would you improve it? The fact that it's hard to trace is exactly the problem I'm asking about. — nodapic, Jul 29 '16 at 16:27
Well, for one thing, smell is highly subjective. Asking for help from people who smell other things doesn't get you very far. — Carl Witthoft, Jul 29 '16 at 17:19
@Carl - Not really; there is general consensus on "bad" smells (e.g. sewage) and "good" smells (e.g. roses). I've found the same to be the case with houses, where things can smell new, clean, musty, etc... I've changed the title and body to be a bit more clear. — nodapic, Jul 29 '16 at 17:44
Just found this thread. Seems to be somewhat related. Still, is there something unique about houses built in the 60s and 70s that make them more susceptible to it and that could be corrected during a renovation? — nodapic, Jul 29 '16 at 18:09
I think your title is missing an "m" right before "old". "Mold" generally rhymes with "roof or water entry problems". — Harper - Reinstate Monica, Jul 30 '16 at 16:09

score 2 · Accepted Answer · answered Jul 29 '16 at 19:43

Normally it's the things you can't see.

Moisture building up behind walls or creeping up through micro-fractures in the foundation will cause mold and mildew to grow fairly quickly.

A fairly cheep way to prevent this is to use a powerful dehumidifier to really dry out offending spaces.

Avoid carpet, as no matter how clean it is, will always harbor bacteria that can cause unpleasant odors.

Old insulation can also be a big source of a constant odor that, while to too offending, is incredibly pervasive.

And finally, mothballs. Some people used to use them as a "catch all" solution to pest problems, and used them so much that the very material of the home absorbed the smell, similar to the way homes that housed prolific tobacco users can smell for years after even with deep cleaning.

"Sometimes it reminds me of rodents, but only faintly." - You may be on to something with mothballs. — Mazura, Jul 30 '16 at 18:12

What causes "old smell" in a clean but older house?

1 Answers1