Possible roof leak. SIP home

Hello, I have a friend with a possible roof leak issue. The home is a 20 year old post and beam with SIP. We are trying to track down the source of the staining coming from the soffit area. Notice the 4 stains running down the siding. The shingle roof looks to be in fair condition and the chimney flashing and cap were replaced 2 years ago. I got right up there and looked around the chimney area and everything looks great. All stained areas were dry and no odors yesterday.
Any tips or ideas where to look? Thanks

Possible ice damming issues. What’s in the attic, did you go there?

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Yes, look in the attic.

Hi Kenyon
Obviously more information or photos are needed. Here are my thoughts anyway.
Gutters are one possibility:
I have seen this type of stain before when a gutter was overflowing the back of the gutter and gets behind the aluminum fascia wrap then flows on top of the soffit material to the siding. If when they built the place the gutters were done before the siding then the siding guys often do not remove the gutters to get there aluminum all the way up and can allow for this to happen.
Given the condition of the siding and the grove in the ground directly below the most heavily stained areas it’s not hard to imagine prolonged overflowing of the gutters. The back of the house in general indicates a lack of maintenance so it’s not likely that the gutters were being cleaned regularly.
The spacing of the staining appears to line up with the groves & seams in the soffit material. The dark staining indicates that the water has soaked through wood picking up tannin along the way.
It appears that there may be a new gutter there. Does the gutter hold water in this area?
Insufficient shingle overhang or lack of drip edge at the eves.
This would also allow water to get in at this area and follow the soffit material back to the siding.
Ice Dams
As @srechkin mentioned Ice dams could be the issue. They would cause this type of staining. Inspect the insulation in the attic & ask your friend if they get large icicles in this area or if snow on the roof melts unevenly. Like around the chimney first. (inspect for insulation around the chimney as it passes through the 2nd floor ceiling.) Assuming this is a masonry chimney. Ice dams are most often a result of inadequate insulation & air sealing in the attic.
Roof leak
My experience tells me that this type of staining is not from a roof leak but it is certainly possible. Go in the attic (assuming there is one) and look for water staining at the back of the sheathing above the wall plate (and back of the fascia if you can)
If the roof is SIP as well as the walls then It is possible that a flashing leak around the chimney (or anywhere on the roof) could flow behind the shingles until it reached the end of the roof SIP which would be right where these stains are. This would also explain how dark the stains are (because the have damaged a lot of sheathing along the way. See the image below.
A lack of air sealing where the wall SIP meets the Roof SIP could allow for ice dams also.
Air Handler
A condensate drain defect in a attic air handler could cause this staining.
Bathroom ventilation
Bathroom ventilation fans not properly exhausted outside through a wall could cause this type of staining. Check for ducts directed into the soffit or just dumped into the attic.

I ended up making this way longer than I had intended. I hope it helps.

Thank you for the ideas. The home does have sip panels on roof and walls. There is no attic, cathedral ceilings and 3 floor. We did find some staining inside the home at the bottom of a roof rafter, like the water had run down from higher up. Im thinking an ice dam like a few of you have mentioned.

What is SIP?
You Yankees said some weird things going on up there.

Is that what you’re going to send to your client? Wow.


It is a very common problem with OSB SIPs. Hence the reason why I wouldn’t ever go with wood SIPS, especially in the roof area. It’s either steel SIPs are no SIPs for me.

It looks a problem where the two SIPs meet. These are the areas where wood OSB SIPs have problems. When the 2 wood SIPs meet, that area creates a cold spot where moisture forms. The wood roof SIPs seem particularly prone to air leakage along joints. Once again, it is the roofs that have these problems, the walls are usually OK.

This is actually a HUGE problem in the wood SIP industry but like many such issues, they will deny that it exists, but just do a Google search and you will find THOUSANDS of hits on this issue.

More on SIPs: https://www.greenbuildingadvisor.com/question/sip-rot-and-remedy

I hope this helps you. :smile:


Not my client. It is @kbertram friends house. I was just replying to his question.
But no I would not send info like that to a client as fun as it might be to hear the realtors response, that much information would make a homeowners head spin.

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Welcome back to our forum, Kenyon!..Enjoy! :smile:

Thanks Larry! Good info. Ill pass this along

Hard to tell from the pic. but the roof boot around the vent stack looks like it is improperly installed.