| Author |
Message |
Robin E. Snyder
Senior Member
Username: robin
Post Number: 244
Registered: 08-2004
| | Posted on Monday, March 23, 2009 - 01:39 pm: |    |
I have this tiny little CMU building, with wood sheathing as the roof deck (vaulted), exposed from below. The architect seems to remember some type of spray on insulation that he thinks can be sprayed onto the underside of the deck and it will just stay attached to the plywood and insulate the little building. Appearance is not a concern. Any suggestions for a gravity-defying spray insulation taht will adhere to the plywood deck? |
Colin Gilboy
Senior Member
Username: colin
Post Number: 175
Registered: 09-2005
| | Posted on Monday, March 23, 2009 - 01:56 pm: | |
Try the spray applied exposed insulation section:
http://www.4specs.com/s/07/07-2300.html
Colin Gilboy
Publisher, 4specs.com
435.654.5775 - Utah
800.369.8008 |
Phil Kabza
Senior Member
Username: phil_kabza
Post Number: 377
Registered: 12-2002
| | Posted on Monday, March 23, 2009 - 07:01 pm: | |
Get a look at the substantial discussion on "hot" roof insulation at www.buildingscience.com. Joe Lstiburek has done a lot of study on the overuse of ventilated attics. He's monitored a bunch of buildings in several climates using spray-applied high density urethane foam installed directly to the underside of roof sheathing as you propose. The stuff is as tough as Gorilla Glue when it sets and will not come down; I've used it on my own projects. Needs plastic thermal separation protection in occupied buildings. Well known manufacturers include BASF and Demilec. |
Curt Norton, CSI, CCS
Senior Member
Username: curtn
Post Number: 140
Registered: 06-2002
| | Posted on Monday, March 23, 2009 - 08:30 pm: | |
if you use a foam spray, it will need a 15 minute barrier to heat on the interior. Instead, check out International Cellulose Corporation at www.spray-on.com They have thermal and acoustical spray systems that can be the finish also. |
John Bunzick, CCS, CCCA, LEED AP
Senior Member
Username: bunzick
Post Number: 1030
Registered: 03-2002
| | Posted on Tuesday, March 24, 2009 - 08:40 am: | |
In this condition, I have used laminated panels. They have nailable base for asphalt shingles, laminated to foam insulation. You can get them with ventilation channels under the nail base so the shingle manufacturer will give a warranty. It may be available with the sheathing as well, requiring only a single step to install--I haven't checked that. |
Randy Cox
Senior Member
Username: randy_cox
Post Number: 54
Registered: 04-2004
| | Posted on Tuesday, March 24, 2009 - 11:03 am: | |
We looked at cellulose at the underside of a roof deck, and the manufacturers told us they would not warranty the installation without something below to hold the cellulose in place. |
Colin Gilboy
Senior Member
Username: colin
Post Number: 176
Registered: 09-2005
| | Posted on Tuesday, March 24, 2009 - 11:11 am: | |
Depends on the cellulose supplier and their products. K-12, Monoglass and Thermacoustics (see link above) are designed to be exposed and have a water-activated adhesive in the mix. Most wall cavity cellulose products do not and would not work.
Colin Gilboy
Publisher, 4specs.com
435.654.5775 - Utah
800.369.8008 |
Wayne Yancey
Senior Member
Username: wayne_yancey
Post Number: 175
Registered: 01-2008
| | Posted on Tuesday, March 24, 2009 - 11:18 am: | |
In addtition to the SIP noted by John B, consider a 2-component closed-cell polyurethane foam by BASF; "Spraytite 178 Series" and a spray-applied thin film thermal barrier. Another is Demilec "Polarform PF7300"; www.heatlok-soya.com
For a thermal barrier checkout BioBased Systems "No-Burn Plus" fire retardant www.biobased.net. There are others from Grace and I believe, Isolatek. |
4specs.com Home Page