Killing mold

[Pat Barry]

Kilz or Binsert. The oil base versions.

[Sam Murdoch]

As promised here are photos. I am now certain that this is efflorescence NOT MOLD.

From a web site on the subject -

"Here are a few tips that inspectors can offer their clients so that they understand the differences:
- Pinched between the fingers, efflorescence will turn into a powder, while mold will not.
- Efflorescence forms on inorganic building materials, while mold forms on organic substances. However, it is possible for mold to consume dirt on brick or cement.
- Efflorescence will dissolve in water, while mold will not.
- Efflorescence is almost always white, yellow or brown, while mold can be any color imaginable.

The second photo shows a corner in shadow but that area was white as in the 1st photo.

Wall-sample.jpg Corner-detail.jpg Corner-no-sheetrock.jpg

I have removed all these areas (and other in the house) and as you can see in the last photo there was definitely water coming down the wall from the skylight above. The skylight is now waterproof again and the wall is dry BUT I have removed the sheetrock and plywood that you see in the photo all the way to the framing. Will let dry - treat with some anti mold (why not) and recover.

Thanks for sharing your thoughts on the subject.

[Jason Roehl]

Looks like you have both there--the first two pics look like efflorescence, and the last pic looks like mold on/in the wood. Use household chlorine bleach diluted with 3 parts water to kill that (take precautions--gloves, goggles, fresh air, etc.). Let it sit for 15-20 minutes before rinsing it off.

[Larry Edgerton]

Sam, when I build a house and they insist on skylights, a bad thing in this climate and I expect yours as well, I make the clients sign a waver that basically says: I know that the skylight will leak in the future, its not if but when."

Usually the leak can be traced back to ice forcing apart the seal/glass connection in the winter months. No matter of care during installation can cure that.

Fill that hole!

Larry

[Andrew Joiner]

Sam, when I build a house and they insist on skylights, a bad thing in this climate and I expect yours as well, I make the clients sign a waver that basically says: I know that the skylight will leak in the future, its not if but when."

Usually the leak can be traced back to ice forcing apart the seal/glass connection in the winter months. No matter of care during installation can cure that.

Fill that hole!

Larry

I'm with you Larry. Why have a hole in a roof? You can let light in with a window.

[Sam Murdoch]

Skylights may not be a wise choice but they are there and so I work in spite of them. I think they'll be OK from here on out.