This Wednesday the Pole Barn Guru answers reader questions about concerns that water might damage girts with use of spray foam, a replacement for A1V, and a request for “sold comps” in the state of Washington.

DEAR POLE BARN GURU: Hello, I am very early in the stages of considering self-building a post frame home. Spending a lot of time researching and learning as much as possible, mostly on Hansen Buildings since you provide such a wealth of information, thanks! My question: How do you go about weather protecting the girts against potential water intrusion from the siding/windows when using closed cell spray foam? I know with other insulation types, a weather barrier like Tyvek is used but this is not usually advisable for spray foam. My concern is that I build my home and water finds a way in and then rots away at my girts since the girts are on the outside of the vapor barrier but under my steel and it can’t dry out well enough. Am I worrying about something that is a non-issue? I am not 100% sold on closed cell spray foam for this reason, however, I do seem to gravitate back to it due to its ability to air seal well and high R value for the thickness. Thanks, CALVIN in HARTFORD

DEAR CALVIN: Appreciate your kind words.

Closed cell spray foam does provide a 100% water seal. If you are using bookshelf wall girts (highly recommended), then vinyl window’s 1-1/2″ nailing flange entirely covers framing around window openings. Even if water where to somehow penetrate steel siding around a window, it would be stopped by closed cell spray foam at juncture with nailing flange – so no way for water to ever get to wood.

While I used closed cell spray foam to insulate when I added an elevator shaft to our barndominium in Northeast South Dakota, I am just not convinced it is economically practical in northern climates.

 

DEAR POLE BARN GURU: Tried to buy the A1V radiant barrier you suggest in your blogs. Apparently it’s no longer available. What product do you suggest in its place? Is there something that can be applied after metal installation that can be sprayed on? I have seen some products that claim to be a condensation stop and sprayed on after the fact which seems like a great idea if it works and is more cost effective than close cell spray foam. Thanks TIMOTHY in CLINTON

DEAR TIMOTHY: You are oh-so-close to my favorite stop for cinnamon rolls! (shameless plug here: https://www.rivercitygrillmissoula.com/)

We discontinued A1V radiant reflective barriers several years ago – as shipping six foot wide rolls became a challenge and trying to install in even moderate winds resembled juggling cats. Every effort has been made to remove older blog articles recommending this as a possible option.

We have been offering to our clients factory applied integral condensation controls (read more here: https://www.hansenpolebuildings.com/2020/09/integral-condensation-control-2/).

As far as products able to be sprayed on after roofing is installed, only two inches or more of closed cell spray foam appears to actually work.

 

DEAR POLE BARN GURU: Our lender is asking for sold comps in order to put together our loan package with land and building costs. Do you keep a list of comps in Washington State? Thank you! SANDRA in GALLUP

DEAR SANDRA: Your sold comps will be any custom designed home, they do not have to be steel roofed and/or sided or even post frame. If your lender cannot grasp this, it might be time to seek a different lender. Many of our clients have used https://www.ffbkc.com/borrow/build-a-home/barndominium-financing/ as they understand barndominiums (and loan in Washington state).