02-13-2009, 08:56 AM
Hotzcatz,
Just when I thought I was letting go of rain screen... You have got me thinking...
You said “single wall construction doesn’t have the problems with mold inside the walls.” So what about those of us who want to use drywall? And perhaps are even thinking of using additional insulation along with the reflective foil, in their non-air-conditioned house to keep it as comfortable as possible.
Yes there are insulations that “resist” mold, like Johns Manville MR Faced, which has the added benefit of being formaldehyde free. I read on the blog that Grabber Kona had paper-less drywall, but it maybe not formaldehyde free. Besides I don’t like the idea that insulation only resists mold...that doesn't sound good. The question still remains, with normal Tyvek the wall is sealed up tight when using drywall, thus preventing a breathable house envelope which then promotes mold growth. Perhaps rain screen technology should be introduced into Hawaii’s building practices as an appropriate way to avoid mold.
In a rain screen style of construction, a water barrier/house wrap is used that allows the air to penetrate but not the water. The house wrap, manufactured specifically for rain screen construction has to be used, and there are many on the market now. This water barrier/rain screen house wrap is installed over the studs or sheathing just like normal Tyvek would be. Next, cementitious furring strips are attached to the studs, (where termites are not a problem the furring strips can be pressure treated wood) this creates a small air gap for moisture to drain away and evaporate. Then the exterior siding is installed onto the furring strips. Some exterior installations call for the finished material to be installed with actual gaps between the panels (hence what I have been envisioning for our house), which allows for air to easily penetrate to dry the wall, and there would be a dip edge at the bottom.
That is the best brief explain I can muster up based on what I know about it. Rain screen construction is becoming mandatory in many areas that receive a lot of rain. It started in Europe, a few years ago in some areas of Canada it is now mandatory, and I think all new construction in Seattle has to be rain screen, but I am not positive on that.
Is this something to discuss and see if it might be a valuable solution to some of Hawaii’s mold problems? The only thing I don’t know about is how humidity comes into play within this air gap.
Barbara Taylor
Hawaii Dreaming
Just when I thought I was letting go of rain screen... You have got me thinking...
You said “single wall construction doesn’t have the problems with mold inside the walls.” So what about those of us who want to use drywall? And perhaps are even thinking of using additional insulation along with the reflective foil, in their non-air-conditioned house to keep it as comfortable as possible.
Yes there are insulations that “resist” mold, like Johns Manville MR Faced, which has the added benefit of being formaldehyde free. I read on the blog that Grabber Kona had paper-less drywall, but it maybe not formaldehyde free. Besides I don’t like the idea that insulation only resists mold...that doesn't sound good. The question still remains, with normal Tyvek the wall is sealed up tight when using drywall, thus preventing a breathable house envelope which then promotes mold growth. Perhaps rain screen technology should be introduced into Hawaii’s building practices as an appropriate way to avoid mold.
In a rain screen style of construction, a water barrier/house wrap is used that allows the air to penetrate but not the water. The house wrap, manufactured specifically for rain screen construction has to be used, and there are many on the market now. This water barrier/rain screen house wrap is installed over the studs or sheathing just like normal Tyvek would be. Next, cementitious furring strips are attached to the studs, (where termites are not a problem the furring strips can be pressure treated wood) this creates a small air gap for moisture to drain away and evaporate. Then the exterior siding is installed onto the furring strips. Some exterior installations call for the finished material to be installed with actual gaps between the panels (hence what I have been envisioning for our house), which allows for air to easily penetrate to dry the wall, and there would be a dip edge at the bottom.
That is the best brief explain I can muster up based on what I know about it. Rain screen construction is becoming mandatory in many areas that receive a lot of rain. It started in Europe, a few years ago in some areas of Canada it is now mandatory, and I think all new construction in Seattle has to be rain screen, but I am not positive on that.
Is this something to discuss and see if it might be a valuable solution to some of Hawaii’s mold problems? The only thing I don’t know about is how humidity comes into play within this air gap.
Barbara Taylor
Hawaii Dreaming
Hawaii Dreaming