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Forgive my ignorance please, need basics on installation

Forgive my ignorance please, need basics on installation


Old 09-26-06, 07:35 AM
Blondeeee's Avatar
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Join Date: Sep 2006
Posts: 24
Unhappy Forgive my ignorance please, need basics on installation


I searched back a year and can't find the way to install the pink insulation. I hope someone will take pity on me and let me know!

My situation: I am trying to insulate the ceiling of an enclosed patio, turned into a room. I live in South Texas and the metal roof get HOT in the summer and radiates heat in. I took out the old 1950s ceiling tiles and caulked all of the holes in the metal roof and the nails protruding thru. Their are now only 2 x 4 s extending the length of the ceiling, butted up to the metal roof. I bought the pink R30 insulation to install inbetween the 2 x 4s. This ceiling was done by the previous homeowner and the space inbetween the 2 x 4 s ranges from 9 inches to 15 inches. I tried to cut the pink insulation and was obviously doing it wrong... made a mess. WHAT IS THE PROPER WAY TO CUT IT INTO STRIPS? One piece I managed to cut, tediously, I held up to the ceiling and I don't know the proper way to install it. I know the paper side should be on the downside. Staples? Duct Tape?
Should I actually get this $250 of insulation UP, do you think I should install another type of vapor barrier under the whole thing? I am planning on puting up a plywood ceiling instead of drywall, should the ceiling leak again. The squirrels are vicious in these parts

Thank you thank you I REALLY appreciate it!!!

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Old 09-26-06, 10:13 AM
Join Date: Feb 2002
Location: US
Posts: 357
Insulation Install--The Least of Your Problems

Try this site for how to cut insulation:


You mentioned that the insulation was R-30 and you only have 2X4s for the roof rafters. How thick is this R-30 insulation? I suspect it is way too thick to fit into the depth of a 2x4 rafter space. Compressing insulation to make it fit into an area destroys the insulating effectiveness of the product. Also, insulation should not be placed directly in contact with a roof underside, you need an air space between the insulation and the underside of the roof.

Provided you have enough space to install this insulation, which I'm not believing you do, you can use wire insulation supports to hold the insulation in place although with your varying bay spacing, you'll have to cut the supports to fit. Easily done with a pair of lineman's pliers. Just make sure the supports are slightly longer than the bay is wide.

I would hold off on this insulation install until you correct two issues you mentioned.

First, you said you have protruding nails though the metal roof. What did you use to caulk these nails and did you do this from the underside of the roof or from on top of the roof? Lower quality caulk on a hot metal roof will deteriorate and loose its elasticity quickly. I get the impression that this was done from the inside, but I may be reading your post incorrectly. This will ultimately result in another leak which will soak the insulation and damage your plywood ceiling. Get a high quality product designed for roofs and make sure the nail head is covered on the top of the roof.

Secondly, you mention squirrels. Have you repaired any areas wher the squirrels might gain access to the underside of this roof area. If you don't keep them out, the insulation will make an excellent nesting area.
Old 09-26-06, 11:20 AM
Blondeeee's Avatar
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Join Date: Sep 2006
Posts: 24

Thank you SO MUCH for the answer and the link. I appreciate your help.

Yes, I caulked all of the nail holes from the bottom/inside of the roof. I did not go onto the top because I was told the metal wasn't sturdy enough to walk on. The area is only 13x15 feet. I did use the high quality caulking for metal roofs though, and after that dried I also used the expanding foam, 3 cans. You are correct about the pink insullation being too thick for the 4 inch space, but it is only about 2 inches too thick. It did compress easily enough to be the four inches, I didn't realize I was destoying it's effectiveness. Would the compressed R30 be any better at all than the thinner R11 that fits?

What would you suggest for the barrier between the roof and the insulation? I need to get on it NOW.

Do you think another vapor barrier across the bottom is warranted?

I have had the space where the squirrels enter fixed very well, and also had a contractor run a vent from the air conditioner in the attic down the common wal with a vent into the room, since there wasn't an attic to use.

So I'm trying... what do you think?

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