Closed cell vs Open cell Post New Topic | Post Reply
Posted: Mar 12, 2013 06:45 PM
Closed cell vs Open cellOk, I have been reading alot about how great spray foam is for insulation. But I have not gotten a straight answer on open vs closed. I am insulating a pole barn for a shop. The size is 48x76x15. The inside will be lined with metal liner. I am leaning towards closed cell. Here are my questions I would like to be answered. Which one should I go with open or closed? How thick should I go on the walls and ceiling? And should I go with a 1 1/2 in the ceiling and blow the rest? So hopefully I get some un biased answers. Thanks again. PS shop is located in iowa and will be heated with in floor heat.
Posted: Mar 13, 2013 03:22 PM
This is a question that I get asked all the time.
The first thing I tell my customers is that closed cell is the best product it has the highest R-value per inch, is basically waterproof, and it adds strength to the building.
But then as we all know that all buildings are a compromise between cost and what we want in energy savings.
So here are some numbers to consider a drum set (2-55gal drums) cost about the same the only difference in cost is the yield or how much finished foam you get out of a set. A set of closed cell foam will produce roughly 4500 board feet of foam or in other words it will cover 4500 square feet one inch thick for roughly an R-7. Now the same set of open cell will yield 15,000 board feet of foam or cover 5000 square feet three inches thick for an R-13. So you can see to get the same R-value closed cell foam will cost twice as much as the open cell and no matter what anyone says R-value is a physics measurement and when comparing foam to foam it does matter.
With that said for the project you are talking about I personally would recommend spraying at least an R-13 (2inches closed cell or 3inches open cell) but more insulation is always better up to around R-40 in the roof. Also I would not insulate a pole barn ceiling, I would spray the foam to the underside of the roof for these reasons; 1 condensation on the underside of the steel roof, 2 with a closed un vented attic there is little to no wind lift to pull the roof off, and the air space in the attic adds insulation.
Hope this helps
Posted: Mar 14, 2013 12:43 AM
|I guess I should have gave some more info on the building. There should be no problems with condensation. The roof has wood sheeting/paper like a house does. Also the roof has s ridge vent. It also has proper vents on the sofits. So I should have no problems there. I think I am going to go with closed cell foam. I am leaning towards spraying 3 inches in the walls. Then in the ceiling spraying 1 1/2 then put in blown insulation to get my r value up to R-40ish. Airpro you never said one way or the other on closed cell or open. If this was your shop how would you do it? Closed or open and how much? Thanks again for the reply|
Posted: Mar 14, 2013 06:55 PM
in the pole barn that is being lined...
i would use the least expensive product to get the most insulation..open cell foam...
you would able to achieve an air impermieable insulation system and plenty of R too at an affordable cost,,yes you will not have the advantage of structural strength(last i knew these buildings came with engineer stamps)...
no you will not a vapor retarting membrane the closed cell affords..so what is the perm of that metal liner??hmmm,,,lets see we can reduce some of the bridgeing effect by more filling the cavity with insulation..we reduce more sound by filling the cavity further with a product that has better sound reduction properties,,,
i would spray 3-4" open cell down on the lid to complete the seal and blow over to R value you want...i do not seal lids with closed cell foam,,a few reasons for me,,a few for you...
if your gonna leave the shop sides exposed..
closed cell only...(to ignition barrier coating or not to ignition barrier coating,,,that is the guestion???)
i spray em both,,,open & closed cell
in iowa(no this is not a solicitation)
ps imho..lol..r10 is the minimum for radiant insulation systems,,double it,,,insulation is the cheapest product in your home 1.9% if you build cheap according to our not freinds at the NAHB,,,consider havin your friendly spray foam contractor spray you 2-2 1/2" to propared grade for a side to side seamless insulation system..perfect,,no breaks,,,right up to the curbs and spead footings...yes a good gun monkey can lay it smooth if the grade is right...compacted dry road stone,,,not sand,,not limes waste,,why would you put that under your foundation anyways partner???..