Originally Posted by
CJRuss
A bit late but years ago I bought a roll of vapor barrier from the local lumber yard and have been protecting my plans with it ever since. CA and epoxy pull off easily. If the plastic gets too messy or accidentally cut just cut off a replacement piece and toss out the used one. I have built atleast one large scale A/C a year plus many repairs and am still on the original roll. Make sure you get a roll of the heaviest guage you can find as it does come in several weights and the lighter ones won't work as well.
Materials used as vapor retarders:
- Elastomeric coatings can provide a vapor barrier and water proofing with permeability ratings of .016 perm rating with 10 mils/min. of coating and can be applied on interior or exterior surfaces.
- Aluminum foil, 0.05 US perm (2.9 SI perm).
- Paper-backed aluminum.
- Asphalt or coal tar pitch, typically hot-applied to concrete roof decks along with reinforcement felts.
- Polyethylene plastic sheet, 4 or 6 thou (0.10 or 0.15 mm), 0.03 US perm (1.7 SI perm).
- Advanced Polyethylene vapor retarders that pass the ASTM E 1745 standard tests ≤0.3 US perm (17 SI perm).
- Asphalt-coated kraft paper, often attached to one side of fiberglass batts, 0.40 US perm (22 SI perm).
- Metallized film
- Vapor retarder paints (for the air-tight drywall system, for retrofits where finished walls and ceilings will not be replaced, or for dry basements: can break down over time due to being chemically based).
- Extruded polystyrene or foil-faced foam board insulation.
- Exterior grade plywood, 0.70 US perm (40 SI perm).
- Most sheet type monolithic roofing membranes.
- Glass and metal sheets (such as in doors and windows)
So what do you mean by "vapor barrier"?