Does anyone know how to deal with greenish gray mold on the border of my window frame and the insulated glazing?

I've never had mold before and my house is 32 years old and very well insulated. The wood in the pictures is impregnated hardwood.

The mold is on all four sides but is thickest at the bottom and lower part of the sides:


My take:

  • Scrub away the solid parts (fungi)
  • Clean with diluted vinegar
  1. Would this be a good idea or could the spores have penetrated too deep into the wood?

  2. Will it need replacement? If no, if it gets worse is there a point of no return?

  3. Does anyone know what kind of mold this even is? I've never seem it before. It's pale green, completely different from the black mold that can grow in the bathroom or the deep green mold that grows on fruit.

3 Answers 3


You are probably getting this because of condensation buildup on the windows plus the wood to feed on at the bottom. Probably no way to totally stop the condensation but simply opening the windows once a week or wiping off the window area with a towel would probably help. Also turn on exhaust fans when taking warm showers or cooking a lot.

To clean just use soap or laundry detergent. Scrub it with a foam pad and a wire brush for wood parts. You will probably need to go through a couple buckets of water. Once everything it is off spray on bleach to the area and wipe off with a towel. Most of the time bleach will have little to no affect on wood unless it pools there but test on a small portion first if you want.


There’s a commercial product you can use called Concrobium. Spray and wipe away the visible mold, spray again and let dry. Should prevent any new mold too.


I agree that the source is likely condensation. I also agree that opening the windows when possible and wiping off the window will both likely help. A fan may help as well (after the mold and its roots are removed... you don't want to spread the spores).

If you don't mind the aesthetic change, you may want to cover those sills with something non-permeable and non-porous. One reason mold grows so well on wood (and paper) is because it is so porous. You can also consider sealing the wood.

It's hard to tell from the photo due to the density of the mold, but it looks like the caulking may be fostering mold growth as well. Replacing the caulking with something more mold-resistant may be worthwhile.

Note that bleach can often kill surface mold, but does not kill the roots.

Since the home is 32 years old, and has no known history of mold, it will probably help to determine what changed that would cause this infestation.

To determine the species, you can send a few samples to a mycobiology lab. Looking at the photo, I think it's likely there are at least 2 different species of fungus present.

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