Confirming insulation in a cathedral
woozy
| Posted in General Questions on
I’m considering an 8 acre property with a metal guest house of 1340 sf OD. The acreage is a good value.
The homeowner/builder is listing this house as having 12″ of foam in the walls and 12″ in the cathedral ceiling. The walls appear to be 12″ thick, but needless to say, I won’t be buying some suspicious cathedral stack on someones’ word. I asked her if it was SIPS panels overhead, but she didn’t know the term.
I would book a a visit from a FLIR/Blower door guy. What else can I do to confirm the description of this property?
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Replies
Lynda,
Most people who are considering the purchase of a house will hire a home inspector before purchasing. Any home inspector should be able to describe the roof assembly of the house you are talking about.
If you are uncertain of the home inspector's skills, be explicit. Say, "Among the details I care about are the materials used to build the roof assembly, the type of insulation installed, and the thickness of the installed insulation." The home inspector's answer will tell you whether you've chosen the right person for the job.
You are reading my mind about my doubting the home inspectors skills, especially in this rural area.
How would they confirm what's inside that void? Would they take off the peak box, or some trim? I apologize, I don't know much about metal stuctures.
Thank you so much for teachng me to be careful!
Lynda,
A good home inspector uses lots of clues. A good home inspector knows the types of homes built in the area where she works, and may know that a certain type of house was built by a certain builder who is known to have worked in the area. A good home inspector recognizes from the shape of the building or the thickness of the roof overhangs whether a roof is likely to be made of SIPs.
A good home inspector has an extension ladder capable of reaching a home's ridge. It isn't very hard to remove a length of ridge flashing, for instance, to peek under the flashing for clues.
Closets or mechanical rooms often provide clues about a home's construction.
In some cases, removing an electrical cover plate can help a home inspector determine what type of insulation was installed.
When in doubt, a home inspector may ask for permission to drill an inspection hole in an inconspicuous location. An inspection hole should be repaired, of course.
Aha! You figgered it out for me.
It's basically a nice open metal structure with a supposedly 12" foam envelope. I'm being insistent about getting to the truth about the foam, not just for the cathedral, but to make sure the metal doesn't substantially affect the interior.
Anyway, I was thinking where to put a hole. I went back through the photos, and there's a ceiling fan.
I've got my hole. Thanks!
Martin,
I think you are overstating the abilities of home inspectors just a little bit. A good home inspector will be able to describe what is visible, and possibly to make inferences based on those observations. But being able to tell what layers of insulation (if any) in closed cathedral ceiling cavities is venturing into Superman territory.
Also, home inspection standards of practice guide inspectors to cause no harm to the building or owner's property. Their client doesn't own the house yet and doesn't have the right to go drilling holes in things. I don't know of any inspectors who would drill a hole into a building cavity without knowing what is inside - wiring, plumbing, air barriers that could be violated, etc. This is not to mention the potential access issues of trying to drill a hole overhead in a tall cathedral.
Even opening cover plates and junction boxes is beyond most standards of practice, though many inspectors will do this when it is warranted.
That said, a good home inspector will know quite a bit about local construction practices and should be able to tell you a lot about the construction details. Still, we're not magicians and we can't see through walls or magically determine what is behind the drywall.
Peter,
I noted, "A home inspector may ask for permission to drill an inspection hole in an inconspicuous location. An inspection hole should be repaired, of course."
That may happen. And the seller may or may not grant the permission. But if the inspector has been hired by a potential buyer with a specific question in mind, the inspector might be motivated to do his or her best to answer the buyer's question.
I used to inspect properties as a first step of a capital needs assessment, so I've done a lot of these inspections. The process may be different for a real estate sale than for a capital needs assessment, but an inspector who strives to help the client is always capable of doing his or her best to answer relevant questions.
I'm sure local practices won't help, since who in the heck would spray 12" of foam to insulate a metal hippie-house, especially if it's $$$ closed cell foam? I'm not completely nuts, I just think there might be value there that others won't recognize.
The ceiling fan idea would work, but maybe it is too high in the cathedral to ask an inspector to look.
Back to the FLIR: There are tons of questions lately about Cathedrals. Maybe thats the Superman vision?
Or not. :)
The little FLIR cameras that use a phone or tablet computer for the display are "worth it" if you are seriously shopping for a higher-performance house. Many flaws can be spotted even without the blower door. The lower-res version is USD$200, the higher res "pro" version runs $400. For your purposes the lo-res version is fine.
They're pretty handy, with lots of potential uses. I've even seen the high-res version being used to quickly spot defective components burning extra power on printed circuit board electronics.
Many home inspectors these days have IR cameras in their toolkits, some of them pretty high quality. While I pushed back a bit on Martin's earlier statement, I absolutely agree that a good home inspection should be a part of your purchase process. The home inspector can tell you a lot about the entire house, not just the insulation. Make your concerns clear, and ask directly how much they can tell you. An IR scan without a blower door doesn't always tell you much, but sometimes it can. For example, if roof and wall surface temperatures are significantly different, you can assume that there are different levels of insulation. You can also see missing insulation and air bypasses in many cases. It's certainly worth the cost of the service.
An energy auditor with a blower door and IR equipment can probably tell you even more. And, if the owners are claiming very unusual construction and performance, it is not unreasonable to ask permission to verify the claims. This could certainly include drilling some test holes, taking off outlet and fan covers, and other semi-invasive techniques that would normally be outside the scope of a home inspection.