Are my SIPS panels deteriorating?
Seven years ago we constructed a shop/studio building in Freeport, Maine. Climate zone 6A, less than a half mile from salt water. Humid climate. The building is built on a slab with radiant heat coils in the slab. Post and beam construction with SIPS panels. The builder erected the frame, then put MR wall board over the frame before installing the SIPS panels. Building has a metal roof. Exterior is wooden siding over Typar and Cedar Breather. We keep the building heated to 60 in the winter, there is no AC for summer. Building is very tight.
Recently we have noticed piles of coarse powder material on the floor of the upstairs. It is found directly under the peak of the gable at the end walls. There is no visible damage to beams or drywall. The powder is mostly white with some dark flecks in it. Just started to happen three weeks ago when we had some abnormally hot weather (100).
Is this SIPS deterioration? If so, what can I do?
Thanks.
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Replies
Ralph,
Does the white powder look like expanded polystyrene? You might have ants. If you have ants, it might mean that you have a roof leak or a flashing problem that is allowing some of your SIPs to get wet and attract ants.
Hi Ralph,
I concur with Martin's suggestion re: ants. I lived in a SIP house that had an infestation. It had nothing to do with moisture though: carpenter ants just find foam to be a perfect material to nest in. (For the record, carpenter ants don't eat foam: they just chew out cavities in it for nesting). The material you're seeing is called "frass" and it's mostly made up of foam and dead ant bits. If you are seeing small bits of wood it's probably OSB skin material: this is worth investigating as it may mean you do have a moisture problem. Coming from the gables peaks I'd be suspicious of condensation in that area, creating an inviting environment for ants. Could be that something didn't get well sealed in that area, allowing moist inside air to condense out on a cold surface in the cooler months.
The solution I took was to locate the ant's nest using a stethoscope (you can heart them chewing even without a scope, but the scope helps you pinpoint the exact location). Then drill small holes and inject a material that the ants find objectionable but which will not harm the foam core. EPS does not like petros as they act as solvents in some cases, causing the foam to disintegrate. Your local pest management company may be a useful resource, especially if they have a green bent.
In most cases the damage done is not extensive enough to warrant reconstructive efforts: carpenter ants tend to create tunnels rather than large galleries. It is possible, however, to inject expanding foam that's compatible with EPS (assuming your panels are EPS core) if you are concerned. No harm done.
Chris Koehn
TimberGudes
Van Isle
Chris,
According to Joe Lstiburek and Terry Brennan, two people I trust, you won't get ants in EPS without a moisture problem. Once the ants sense a humid environment, they move in. So I think that Ralph should identify the moisture problem attracting the ants, whether it is condensation or a roof leak.
Ralph, is the frass under both ends or just one end of the house? What is the orientation of the ridge--North/South?
I work in Freeport and it was indeed hot a few weeks ago (much nicer today!), but we were also getting rains out of the south/southeast which typically only happens this time of year. It's possible for wind-blown rain to infiltrate the roofing at the peak, if your roofer did not wrap the roof/wall intersection with ice & water shield.
That source of moisture would attract ants, and is much more likely than condensation this time of year. Ants need water like the rest of us. You could try to inject some Borax powder (Royal River Natural Foods probably carries it) but it would be better to fix the moisture source.
Thanks to all of you who have posted.
I have looked at the white powder with a magnifying glass and it does appear to be 'frass'.
Axis of the roof ridge is NNW. Problem appears at both ends, though it is much more pronounced on the end facing SSE.
Humidity inside the building is often >50% in the summer. Note that we do not live in the building, so no moisture load from kitchen, bath, or laundry. Moisture source is atmospheric.........but the building is so well insulated that it's always much cooler than the outside. So pulling more air thru the building in the summer does not seem like a solution. Any thoughts on reducing the humidity.
Thanks.