Attic spray foam in tight edge corners

[DamonM]

My 24x24x10 shop is going up right now. The contractor is planning on putting in a ceiling liner unless I tell him otherwise. My plan is to insulate the walls with closed cell spray foam. My original thought for above was to spray foam under the osb roof deck. If I let my contractor put the ceiling liner in I could have the ceiling spray foamed from above (load bearing trusses and osb ceiling will handle it). The concern I have is with a ceiling liner and a 4:12 pitch, how do they get into the shallow tight corners of the roof? And how do I know they actually got the insulation in there okay? It would save me $1000 in spray foam if I go with the ceiling as I won't have to do the gables or larger surface area of the roof. On the other hand if I don't do the ceiling and have the entire roof deck and gables sprayed I can see that the work is actually done. With a 4:12 pitch there is a little more space where heat will rise in the winter but I can put a couple fans up and redirect it down.

Thoughts? Suggestions?

 

[yeldogt]

I would do the whole building. Done! No issues no problems. If you want to use the space above for some storage -- you have a conditioned place for it.

You can still do the ceiling .... after

 

[Toyomech]

The answer is exactly as it appears. Alot of our customers think we have a long wand or some other method to reach barely accessible areas. There are some long shot tips and gun extensions on the market but they are mostly gimmicks. A man has to physically lay on his stomach or back and reach into the shallowest corner to spray foam in a situation like this. Generally its pretty miserable and you would be doing yourself and the installer a huge favor by doing the roofline before you install the ceiling. Then you can see that it was done correctly and they can easily work in those areas.

 

[DamonM]

Thanks for the input. I met with a spray foam contractor and agreed that it would be better to spray under the roof deck, the gables and the walls. The ceiling liner will be left off so they have good access.

 

[Bretny]

I wouldnt put the ceiling in either. It will make insulating a pain and very hard to view after the fact.