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chris5150
Unsightly Brown Stains on Siding

Hello,

We purchased a home in Oct. and all through the winter, we have had brown stains (looks like coca cola) show up in long streaks on our wood siding. What is this, and where is it coming from? It is really unsightly, and we are perplexed. Any ideas?

Chris

MLBSF
Re: Unsightly Brown Stains on Siding

sounds like rust from the nails holding the siding on. other possiblity is rust from the nails holding the sheathing on if water is geting behind the siding.

chris5150
Re: Unsightly Brown Stains on Siding

thanks for this. It really is a strange substance.. not so much just a rust stain as a sticky "coca-cola-like" resin. Would this still be from the nails?

MLBSF
Re: Unsightly Brown Stains on Siding

what info can you give us on the house? how old is the siding? how was it attached? what material is the siding? is could be sap from the wood siding or sheathing. is the sheathing pine boards, plywood or particle board. some woods that aren't very old leak sap as they age.

chris5150
Re: Unsightly Brown Stains on Siding

It is an older house (1920s) that was recently gut rehabbed, but exterior was only painted. Siding is wood (cedar) and rather old, and the sheathing is plywood. The shingles and sheathing have been in place for a long time as far as I can tell- we have only owned the home since October.

BTW, is looks like some sap is dripping from the un-vented soffit too.

MLBSF
Re: Unsightly Brown Stains on Siding

cedar is an extremely oily wood. my guess would be that water is getting into the shingles and washing out more of the old oil leaving a residue that you're seeing. i'm sure some other's will have some other ideas so check back later and i'm sure you'll have some additional posts.

cspalding22
Re: Unsightly Brown Stains on Siding

Did you have ice dams this winter? Sometimes when it melts it can leak through the wall and make contact with the wood between the siding and your wall resulting in a brownish stain on the exterior.

cjsand
Re: Unsightly Brown Stains on Siding

Could also be old stains coming back through the new paint?

Re: Unsightly Brown Stains on Siding

This brown staining is caused from ice dams.

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bl15
Re: Unsightly Brown Stains on Siding

I have similar stains on my vinyl siding. the house was built in 2003 and the sheeting under the siding is particle board. The stains are more like a syrup/coca cola substance. If it is coming from the sheeting, does that mean I have water infiltration in that area? it starts at the bottom of the second floor and runs to the bottom of the first floor. It appears to be stemming from the weep holes in the bottom of the siding.

Re: Unsightly Brown Stains on Siding

We had this kind of stains on our second house too. It turns out they're from the nails that rusted over time. Due to constant raining, the stains seemed to spread. We tried removing them in some ways but haven't been successful so far.

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