I recently had a TuffShed portable building built in my backyard. It is 12' X 24' with 8' walls and the ceiling is not vaulted. The shed is on concrete blocks. I then had electricity installed, cable/satellite installed, then had the building sprayed with open cell foam. The walls have 3.5" off foam and the ceiling has 5.5 " of foam. The walls are approx. R-13 and the ceiling is approx. R-20, per the installer.
So, at this point, I have not put up any interior walls, whether it be plywood, paneling or sheet rock. I put a 14K BTU portable AC unit that I had, to see how the insulation would fare. The following afternoon, in the central Texas heat the best my 14K portable unit could do was hold the room at 83-85 degrees F. I was not expecting this. I expected 76 degrees no problem. so the next day I borrowed a friends 8K BTU portable unit and ran both together. That's 22K of BTU. The next afternoon, both portable ac units working together, could not get the room temperature below 84 degrees F. What is going on?
The building gets approx. 6 hours of direct Texas sun.
It is very adequately insulated.
I considered that it was so well insulated, that it created a negative pressure, making it difficult for the portables to push enough air out of the building. SO I opened a window about 2" and that helped to reduce the afternoon temps to 82-84 degrees F. in the afternoons.
That is where I'm currently at. SHould I go ahead and either paint the ceiling foam with an acrylic paint, to further seal the foam?
Do I go ahead and install plywood, paneling, sheet rock?
Why can't I get my afternoon temps down into the 70's at least. THat much portable unit BTU's should have no problem keeping that building cool.
I even insulated the doors with 1.5 inches of open cell spray foam.
The floor is 3/4" plywood, which is not insulated below it. It does have 2 coats of a good paint.
My certified HVAC man has run the numbers on his 'load calculator' and he is completely baffled as well.
Any ideas would be highly appreciated. And if you'd like further information about this building, please ask.
I don't have much hair left to pull out. So please help.
My only idea left to do, is install interior walls over the foam and/or paint the ceiling with a water based acrylic paint.
:sad:
So, at this point, I have not put up any interior walls, whether it be plywood, paneling or sheet rock. I put a 14K BTU portable AC unit that I had, to see how the insulation would fare. The following afternoon, in the central Texas heat the best my 14K portable unit could do was hold the room at 83-85 degrees F. I was not expecting this. I expected 76 degrees no problem. so the next day I borrowed a friends 8K BTU portable unit and ran both together. That's 22K of BTU. The next afternoon, both portable ac units working together, could not get the room temperature below 84 degrees F. What is going on?
The building gets approx. 6 hours of direct Texas sun.
It is very adequately insulated.
I considered that it was so well insulated, that it created a negative pressure, making it difficult for the portables to push enough air out of the building. SO I opened a window about 2" and that helped to reduce the afternoon temps to 82-84 degrees F. in the afternoons.
That is where I'm currently at. SHould I go ahead and either paint the ceiling foam with an acrylic paint, to further seal the foam?
Do I go ahead and install plywood, paneling, sheet rock?
Why can't I get my afternoon temps down into the 70's at least. THat much portable unit BTU's should have no problem keeping that building cool.
I even insulated the doors with 1.5 inches of open cell spray foam.
The floor is 3/4" plywood, which is not insulated below it. It does have 2 coats of a good paint.
My certified HVAC man has run the numbers on his 'load calculator' and he is completely baffled as well.
Any ideas would be highly appreciated. And if you'd like further information about this building, please ask.
I don't have much hair left to pull out. So please help.
My only idea left to do, is install interior walls over the foam and/or paint the ceiling with a water based acrylic paint.
:sad:
