Attic Insulation Question

[Carnak]

Carnak,
I'm not familiar with that method. Do you have a link where I could read more?

its in every mall with a flat roof , built up deck and a membrane, you can do the same on a slope, I have

try building science search for BSD-102

look at figure 7, photo 4 and figure 8

They did an interesting study of the LA superdome after Katrina, as its roof was similar to figure 8, they now recommend filling in the flutes with foam.

The roof of the superdome had hundreds of bullet holes in it before Katrina hit.

water flowed all over in those hollow flutes

[Carnak]

My attic is 1.5 inches of foam above a sloping concrete deck, there is white metal roofing. Maybe R7 total.

As far as keeping the heat out I think it outperforms R30 at the ceiling plane in a vented attic.

Before I turned on the AC the attic was a degree hotter than ambient. I believe that was better than a 140F sauna with a fibreglass air filter in between the ceiling joists.

[jax1]

great link Carnak!
I like that method. Leaks should be easy to find before doing structural damage. Is it cheaper to build than spray on the underside?

[Carnak]

I bought a half built, abandon concrete structure that was to be 4 apartments. The majority of the materials to finish the job were on site.


I had 2 @ 20 ft containers with about 15,000 reddish spanish roof tiles on the site that came with the property. They would have been difficult to install and I was going to blow the foam on the underside of the deck.

I ended up abandoning the scheme, as I figured the dark tiles, the concrete beneath it would have been a very substantial thermal mass, and the colour would of encouraged it to heat up. The foam benenath would have slowly allowed stored up heat to trickle in and by the time the mass cooled off the sun would be up again.

So I decided to keep the heat out of that mass as best as I could in the first place.

So, we hilti nailed pressure treated 2x4s on the flat to make a surface to screw the metal roofing to, In between the 2x4s is 1.5 inches of foam. I put tar paper over that then the white metal standing seam roofing. After going through a category 5 storm, it was very obvious that standing seam roofing is the best to have.

It was a financial decision, however it was the cost of trying to stick roof tiles to smooth sloping concrete that was the problem. It would have been very labour intensive.-

I sold about 3000 tiles, we held out for too much money on the rest, and the roof repair rush after a hurricane ended. Now I have 12,000 tiles I cannot give away.

[triforcharity]

Hi ya'll!!

I am new to the site, so I am going to let this be my first post.

I have this stuff called Hy-Tech Thermal Solution. It is a paint laced with some type of ceramic. This helps to cut down anywhere from 20-80% of the radiant heat in the attice space. You simply paint it on the entire roof, right on the shingles. I have it on mine, and am THUROUGHLY impressed.

Check out the link.

http://www.hytechsales.com/prod200.html

[energy_rater_La]

here we go again...rb paint vs rolls of rb attachec to roof decking...

[triforcharity]

here we go again...rb paint vs rolls of rb attachec to roof decking...

No, this is something that can be used in ADDITION to rolls of insulation. I never said that they were better, just s suggestion. Especially for houses with exposed Tongue and Groove ceilings, such as mine.

[buddylee]

Has anyone else thought about using spray foam insulation on ductwork? I wrapped the metal duct at my dads house with 2 1/4" fsk and then two wraps of reflectix with an airspace between them and it has helped quite a bit as he has no shade whatsoever.

[kenny mac]

Has anyone else thought about using spray foam insulation on ductwork? I wrapped the metal duct at my dads house with 2 1/4" fsk and then two wraps of reflectix with an airspace between them and it has helped quite a bit as he has no shade whatsoever.

The foam is ugly... it is awesome !!!

[triforcharity]

The foam is ugly... it is awesome !!!

Does this meet the NFPA Standards for flameability???? If it does, than it looks much easier than wrapping it.

[kenny mac]

Does this meet the NFPA Standards for flameability???? If it does, than it looks much easier than wrapping it.

THIS IS PASTED FROM THE IRC 07 SUPPLIMENTS


M1601.3 Duct insulation materials. Duct insulation materials shall conform to the following requirements:
1. Duct coverings and linings, including adhesives where used, shall have a flame spread index not higher
than 25, and a smoke-developed index not over 50 when tested in accordance with ASTM E 84 or UL 723,
using the specimen preparation and mounting procedures of ASTM E 2231.
Exception: Spray polyurethane foam shall be permitted to be spray applied to the exterior of ducts in attics
and crawl spaces subject to all of the following:
1. The flame spread index is not greater than 25 and the smoke-developed index is not greater than
450 at the specified installed thickness.
2. The foam plastic is protected in accordance with the ignition barrier requirements of Sections
R314.5.3 and R314.5.4.
3. The foam plastic complies with the requirements of Section R314.

[buddylee]

Originally Posted by kenny mac
The foam is ugly... it is awesome !!!

Whats the R-value and what kind of time savings do you get from it.

[kenny mac]

Whats the R-value and what kind of time savings do you get from it.

Closed cell foam is 7 Rs per inch.... and you can't pay me to put a system in an unconditioned attic... if I can help it...

So one of the major steps omitted is sealing all the joints and connections....
You can be a bit more liberal on your take off placement...
No wrapping taping or stapling...
The boots are a breeze....

So yea... it saves a bunch of time....

It seems to cost a bit more at the end of the day...

Thanks