Spray foam ceiling questions

[HELLSUNICORN]

I just built a 24x20 addition to my pole barn. Its is common pole barn construction with trusses and purlins. The purlins are 24 inches on center and they are covered buy steel sheets. I plan on spray foaming the ceiling.

I have planned on spray foaming the ceiling from the beginning because I have a friend who does it for a living. Now that the building is done and I am ready to spray it we had a discussion about when he can do it. During this discussion some things came up that worry me.

I am looking for anyone who has had their roof spray foamed to answer some questions for me.

I only screwed down the sheet steel on the high points. The foam guy tells me I need more screws because the foam may lift up the steel and make it wavy. How many screws does it need? Did your steel lift?

How violent is the foam? He says it will expand any cracks and possibly bend the purlins if they are not secured.

How does it look? I have seen pictures on the internet and pictures of what he has done but he is warning me that the interior won't be smooth. I understand this but I would like to see more pictures of whats out there to get a better idea.

Anyone who has had this done please tell me about your experience. I think he is warning me for worse case scenario because we are friends. But now I am nervous.


Thanks in advance.

 

[kj_mustang]

You can see pictures of my closed cell spray foam walls in my build album.
Picture Album
The roof was sprayed with closed cell than open cell over that so it will not look the same. My roof steel has a screw in every flat area. You can zoom in on one of my roof pictures and see them. I had no issues with my roof or wall metal from the foam but it is all screwed down very well. My building was done by a large commercial pole building company.

 

[bjcouche]

I have a 40x64 pole building and had the walls and the underside of the roof sprayed with 2-3" of closed cell foam. My steel is screwed down as per the manufacturers recommendations and just like HELLSUNICORN's pictures show. I didn't know you could screw the residential steel panels through the ribs and not have them leak. I think you can do that with commercial panel (the ribs are 2-3X as tall and wide) but I don't know about the small rib type.
It's possible that I do have some slightly wavy metal, but I'm not sure if it was like that before the foam was sprayed or not. On my building it's not noticeable. I could foresee though that if you only have screws in the ribs, this might be exacerbated because the metal bends real easy between ribs with no screws holding it down between ribs.
The foam really strengthened the building. Before the walls were like a drum and knocking on them would create a racket. Any wind or clouds overhead would cause the would building to ping, bang, bong, etc as the metal expanded and contracted. Now when you bang on a wall with your fist from the outside it feels like a dull thud, like there's plywood behind it.
I can say though that before the foam was installed, in the summer the shop could double as an oven. Standing next to a wall, you could feel the heat radiating off the metal, and if you touched it, with your arm you could be burned. After the foam was installed, the shop inside is about outside temp (without any cooling) and the inside of the foam is cool to the touch.
Spray foam is expensive, yes, but worth every penny.

 

[Jo Diesel]

So you have steel on the bottom of your trusses like I do and you are spray foaming on top? Or are you spraying directly on underside of roof?
If you are doing a ceiling that is attached to bottom of trusses he needs to do a tack coat and let it expand for like a minute then go back over it. You just need to work back and forth. That's how my brother does it that is certified.
If you are spraying directly to bottom of roof deck, the manufacturers do not recommend it. The steel and foam expand at different rates and the foam can let go of the steel. This is directly from the cert class.

 

[bjcouche]

I have no ceiling, I have no drywall. My trusses are steel and spaced 16 feet apart. The spray foam was sprayed directly to the bottom of the roof sheet metal decking. The same goes for the walls. The foam was sprayed directly to the inside of the sheet metal. I had quotes from 3 local companies and all 3 were going to do it the same way. This worked out well in my application.

Brian