Posted: Tue Mar 28, 2006 3:00 pm
angib wrote:alaska teardrop wrote:If you're going to use a wrap type barrier, a 4 to 6 mil polyethylene sheet (the plastic that Rob mentioned) would be a better choice.
It would also prevent the structure either side of it from being glued together.
Having an outer skin attached to an inner skin seems more important to me than having a vapour barrier between them, but maybe I'm wrong.
Andrew
- Of course Andrew, you are correct. In Jeanett's case, she can tape just the gaps and glue to the extruded polystyrene and glue/screw to the frame. Thereby, accomplishing both objectives that she raised.
- In Karen's case she didn't mention which type of insulation that she planned to use.
- The polyethylene sheet should be used as a vapor barrier for the following:
- Expanded polystyrene board
- Expanded polystyrene bead
- Fiberglass batt
- Cellulose
- Rock Wool
- Perlite
- Vermiculite
- I personally wouldn't recommend any of them for use in a small trailer because of the water absorption and/or moisture damage factors. Also, creating a truely effective vapor barrier in a trailer with a wrap would be very difficult and time consuming.
- Foamed in place urethane is a good choice if it's closed in, all the air pockets are filled and the inside of the wood framing is covered with a vapor barrier.
- Urethane Isocyanurate (R-max) with the foil face inward is an effective vapor barrier. However, the edges and every cut in the foil needs to be taped or otherwise sealed. Also, it's not very structural and tends to break when bending.
- I have used the foil bubble type insulation, but I don't think that I will again. I'm not sure of the R-value claims in cold weather when installed in a trailer in the way that I used it. Maybe, someone else is more knowledgable and has an opinion about it's use in a trailer.
- Tracy wrote: I duct taped around the outside of my insulation to framing.
- Duct tape isn't considered a vapor barrier because moisture effects it's adhesion and probably permeable by water vapor. The Venture tape is made for the purpose. It will stick and stay on insulation, wood, steel, aluminum and polyethylene sheet.
- I really should claim no expertise other than paying close attention to and study of insulation and vapor barriers for building homes in the arctic.
- Hope all this helps.
- Fred