I have an issue with one of my roof metal (aluminum) SIPs. It appears the panel is sagging about 1/4"-1/2". The sag appears to be worse when the temperature is lower (below 80 F), and during the hot part of the day the sag seems to disappear (or at least is greatly reduced). The previous owner had a pot rack hanging from the panel, which may have caused the issue, but I have no way of knowing. (Pictures in below links) Looking for advice on repair method, and any other opinions/information. Thanks. https://drive.google.com/open?id=0B3m9LPQUkq8FRXJGT01QM2dFYW5WQkpEZzdsVDZVTEJOeng4 https://drive.google.com/open?id=0B3m9LPQUkq8FX0w1MUE1M3dqYU8xZlpLZ1Zuc1VLUEZBMk53

Posted By dugas on 17 Oct 2018 05:15 PM
I have an issue with one of my roof metal (aluminum) SIPs. It appears the panel is sagging about 1/4"-1/2". The sag appears to be worse when the temperature is lower (below 80 F), and during the hot part of the day the sag seems to disappear (or at least is greatly reduced). The previous owner had a pot rack hanging from the panel, which may have caused the issue, but I have no way of knowing. (Pictures in below links) Looking for advice on repair method, and any other opinions/information. Thanks. https://drive.google.com/open?id=0B3m9LPQUkq8FRXJGT01QM2dFYW5WQkpEZzdsVDZVTEJOeng4 https://drive.google.com/open?id=0B3m9LPQUkq8FX0w1MUE1M3dqYU8xZlpLZ1Zuc1VLUEZBMk53

dugas,
aluminum SIPs are primarily used for patio enclosure and carports,
Is yours a different use?
is it exposed to a snow load?
what is the thickness and span?
it appears that one is sagging , but the other is not?
do you know the manufacturer?

Chris,

Thanks for the quick response.

Is yours a different use? - It is a house/camp.
is it exposed to a snow load? - No
what is the thickness and span? - I believe 6", span is 15'
it appears that one is sagging , but the other is not? - The adjacent panels do not appear to sag.
do you know the manufacturer? - Structall

Posted By dugas on 17 Oct 2018 07:03 PM
Chris,

Thanks for the quick response.

Is yours a different use? - It is a house/camp.
is it exposed to a snow load? - No
what is the thickness and span? - I believe 6", span is 15'
it appears that one is sagging , but the other is not? - The adjacent panels do not appear to sag.
do you know the manufacturer? - Structall

dugas,
our panels are used for housing and commercial buildings, typically the aluminum would not be used for a house due to the extreme expansion and contraction , especially on a roof
heat on the outer aluminum skin will expand and cause the entire panel to crown up, then as it cools settles back down
if the panel is truly 6" , it doesn't sound over spanned ,on the other hand if it is less than 6" that may be the problem

Unsupported span
are spacing of support beams same for OSB faed sips as your metal panels at same total panel thickness?
I can see why you say aluminium faced would have a problem if not insulated from summer heat

Posted By scottishjohn on 18 Oct 2018 07:57 AM
Unsupported span
are spacing of support beams same for OSB faed sips as your metal panels at same total panel thickness?
I can see why you say aluminium faced would have a problem if not insulated from summer heat

Permatherm's galvalume SIPS typically have greater span capabilities than OSB SIPs
OSB can sag under it's own weight

the aluminum panels do not need protection from the sun, they are actually made to be used bare, the sag or deflection is allowable and at 15ft the sag could be up to 3/4" and still considered to be within allowable tolerance.
however if only one is moving then it it gives me pause to wonder why?
the crowning is just an inherent property to the aluminum skin , I actually would not recommend covering with anything , especially if the material was darker it could aggravate the crowning and aluminum is not made to carry an additional roof covering , it is a finished product for sunrooms, patio covers and carports