Open Cell Spray Foam - crawl space and interior walls

ChrisStratton · 01-07-2018, 07:57 AM

This runs to ground/grade at the back upper corner.

winterh · 01-07-2018, 11:51 AM

I was thinking of something I believe they call duo rock board. It is about 3/4 inch thick concrete with mesh in it to hold it together. It is often used under tile applications but I was thinking it may be a good choice. I would do more research into what is best product but if you decide to encapsulate you want something that looks ok on the exterior and that will allow you to spray and hold the foam on the inside. If these were put inside of the slats I think you could keep the current look on the outside. I will be heading up mid week and will take some pics and post them or PM me and you are welcome to come by and take a look. It was not cheap but it was worth it. About $5000 for a 1600 sq ft footprint if i remember right.

ChrisStratton · 01-07-2018, 12:17 PM

Quote:

Originally Posted by winterh

About $5000 for a 1600 sq ft footprint if i remember right.

Hi Winterh - i'd be interested in learning more about your company and how much foam they applied, etc. Sounds like the right approach, if they can get under the farthest reaches. Right now, I'm in FLA and prolly won't be up until the snow is gone (April)?

Thanks for the help in this, and the kind offer to visit!

DickR · 01-08-2018, 12:04 PM

The cement board product referred to by Winterh is Durock (eg. https://www.homedepot.com/p/DUROCK-N...2965/202263276). If you use that on the inside of the skirt, then you might consider cut/glue application of foam board (2-4") over the Durock for insulating, with beads of can foam at the edges and joints to seal them.

Some good reading on building an unvented crawl space can be found here: http://www.greenbuildingadvisor.com/...ed-crawl-space. In addition to the info in that blog, there is a long "Related Articles" list of links to more info on the general subject.

When I mentioned the use of borate-treated cellulose, what I had in mind was dense-pack blowing of the cellulose into the joist cavities, using a sufficiently powerful blower, like the contractors would have. Sometimes the blowers available at the big box stores are ok for a loose blow into an attic, but not powerful enough for dense packing to upwards of 3 lb/cuft density, needed to counter settling of loose-blown cellulose, as in an attic. If you are redoing the floors inside anyway, then you have more options for insulating. If you have sufficient ceiling height to lose a couple of inches, you could lay down rigid board over the present floor, then a layer of T&G plywood, and finished flooring. But if you see this structure as being regularly occupied year round, then overall comfort might be better with an enclosed and heavily insulated crawl space, with no floor insulation at all, since the floor and crawl space would be reasonably close to interior temperature.

SIKSUKR · 01-09-2018, 10:47 AM

Looking at those pics, if that were mine I would probably lean towards insulating the perimeter walls with rigid and laying a poly vapor barrier on the ground.

ChrisStratton · 01-16-2018, 02:45 PM

Thank you, each/all!

VitaBene · 01-16-2018, 03:47 PM

Wow, what a great thread! Thanks to those who contributed, it was very informative!

The end result is what a lot of the 4 season campers do with hay bales between the floor and the ground come winter, I guess.

01-07-2018, 07:57 AM	#1
ChrisStratton Junior Member Join Date: Oct 2017 Posts: 15 Thanks: 0 Thanked 0 Times in 0 Posts	what it looks like This runs to ground/grade at the back upper corner. Attached Images

01-09-2018, 10:47 AM	#5
SIKSUKR Senior Member Join Date: Apr 2004 Posts: 5,075 Thanks: 215 Thanked 903 Times in 509 Posts	Looking at those pics, if that were mine I would probably lean towards insulating the perimeter walls with rigid and laying a poly vapor barrier on the ground. __________________ SIKSUKR

01-07-2018, 11:51 AM	#2
winterh Senior Member Join Date: Jun 2009 Posts: 249 Thanks: 30 Thanked 135 Times in 62 Posts	I was thinking of something I believe they call duo rock board. It is about 3/4 inch thick concrete with mesh in it to hold it together. It is often used under tile applications but I was thinking it may be a good choice. I would do more research into what is best product but if you decide to encapsulate you want something that looks ok on the exterior and that will allow you to spray and hold the foam on the inside. If these were put inside of the slats I think you could keep the current look on the outside. I will be heading up mid week and will take some pics and post them or PM me and you are welcome to come by and take a look. It was not cheap but it was worth it. About $5000 for a 1600 sq ft footprint if i remember right.

01-08-2018, 12:04 PM	#4
DickR Senior Member Join Date: Apr 2008 Location: Moultonborough Posts: 751 Thanks: 4 Thanked 259 Times in 171 Posts	The cement board product referred to by Winterh is Durock (eg. https://www.homedepot.com/p/DUROCK-N...2965/202263276). If you use that on the inside of the skirt, then you might consider cut/glue application of foam board (2-4") over the Durock for insulating, with beads of can foam at the edges and joints to seal them. Some good reading on building an unvented crawl space can be found here: http://www.greenbuildingadvisor.com/...ed-crawl-space. In addition to the info in that blog, there is a long "Related Articles" list of links to more info on the general subject. When I mentioned the use of borate-treated cellulose, what I had in mind was dense-pack blowing of the cellulose into the joist cavities, using a sufficiently powerful blower, like the contractors would have. Sometimes the blowers available at the big box stores are ok for a loose blow into an attic, but not powerful enough for dense packing to upwards of 3 lb/cuft density, needed to counter settling of loose-blown cellulose, as in an attic. If you are redoing the floors inside anyway, then you have more options for insulating. If you have sufficient ceiling height to lose a couple of inches, you could lay down rigid board over the present floor, then a layer of T&G plywood, and finished flooring. But if you see this structure as being regularly occupied year round, then overall comfort might be better with an enclosed and heavily insulated crawl space, with no floor insulation at all, since the floor and crawl space would be reasonably close to interior temperature.

01-16-2018, 02:45 PM	#6
ChrisStratton Junior Member Join Date: Oct 2017 Posts: 15 Thanks: 0 Thanked 0 Times in 0 Posts	Thank you, each/all!

01-16-2018, 03:47 PM	#7
VitaBene Senior Member Join Date: Jul 2007 Location: Moultonborough Posts: 3,587 Thanks: 1,625 Thanked 1,640 Times in 843 Posts	Wow, what a great thread! Thanks to those who contributed, it was very informative! The end result is what a lot of the 4 season campers do with hay bales between the floor and the ground come winter, I guess.