Do you have any advice when a customer insists on using vinyl wallpaper over drywall as an interior finish?
One detail has the building framed with 2 x 6 wall studs and 1/2″ cdx sheathing which is covered with a roll-on membrane. Stud space is filled with R-19 unfaced fiberglass batts. Exterior cladding is brick veneer, with 1″ air space between sheathing and back of brick. Ventilation of air gap is provided by installing rectangular vents at head joints in masonry, one every 24″ at bottom of wall, another row at top of wall. Use of mortar net is called for at vents to prevent mortar droppings from plugging vents and weeps.
Another detail subtitutes Zip brand OSB roof sheathing, for 1/2″ cdx and roll-on membrane.
I would appreciate thoughts on which detail would be preferred , and any other comments. We are located in South Central Kansas. I have tried, with no sucess, to discourage use of vinyl wallpaper.
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Try "I'll agree to vinyl wallpaper only if you sign a release of warranty for the wall assembly".
...or you could try, "You can use all the vinyl wallpaper you want, as long as it it not used on the exterior walls".
What the others said. You should also make them sign a document agreeing that vinyl wallpaper can only be used if the house is never air conditioned.
Or I suppose you could build an interior ventilated rainscreen with two layers of drywall separated by an air space, with a ventilation channel open at the bottom and open at the top. Then vinyl wallpaper could be used.
Some vinyl wallcovering is available with microperforations for some vapor permeability. You should try to use that at the exterior walls.
Also, your roll-on membrane may be available in a vapor-permeable formula. If it is, you should probably use the vapor permeable type. I'm not sure which way the vapor drive would be in your region, but avoiding a "vapor sandwich" always seems like good advice.
It's rather astounding that the only apparent concern on a green building site about the use of vinyl wallpaper is its lack of permeability. The following is what we should all be concerned about.
Environmental Impacts of Polyvinyl Chloride (PVC) Building Materials
A briefing paper for the Healthy Building Network
by Joe Thornton, Columbia University’s Earth Institute and Department of Biological Sciences, Ph.D., M.A., and M.Phil. degrees in Biological Sciences from Columbia University
Global vinyl production now totals over 30 million tons per year, the majority of which is directed to building applications, furnishings, and electronics. The manufacture, use, and disposal of PVC poses substantial and unique environmental and human health hazards.
PVC production is the largest use of chlorine gas in the world
Hazardous by-products are formed throughout the PVC lifecycle:
By-products of PVC production are highly persistent, bioaccumulative, and cause:
• disruption of the endocrine system
• reproductive impairment
• impaired child development and birth defects
• neurotoxicity (damage to the brain or its function)
• immune system suppression.
Dioxins are formed during numerous stages of the vinyl lifecycle
There is no known safe dose of dioxin and is the most potent synthetic carcinogen ever tested.
Phthalates: Vinyl is the only major building product in which phthalate plasticizers are used extensively – more than 5 million tons of phthalates every year. They leach out of the plastic over time into air, water, or other substances with which vinyl comes in contact. Phthalates have been found to damage the reproductive system and are known carcinogens.
Lead and other heavy metal stabilizers: Highly toxic metal stabilizers are added to vinyl for construction and other extended-life applications, including lead, cadmium, and organotins, which are released through out the vinyl product lifecycle, including from interior vinyl building products.
Flexible PVC harms indoor air quality: Flexible vinyl products appear to contribute to the health hazards of poor indoor air by releasing phthalates and facilitating the growth of hazardous molds. PVC phthalate exposure may be linked to asthma and other pulmonary conditions.
Vinyl wall covering encourages toxic mold growth: Vinyl has been cited as the interior building material most likely to facilitate the growth of these molds.
Chlorine production consumes enormous amounts of energy: Chlorine production is one of the world’s most energy-intensive industrial processes, consuming an estimated 47 billion kilowatt hours per year - equivalent to the annual total output of eight medium-sized nuclear power plants.
Chlorine production causes mercury pollution: In about a third of world chlorine production, very large quantities of mercury are released into the environment.
PVC is extremely difficult to recycle: Very little PVC is recycled, and this situation is unlikely to change in the foreseeable future.
PVC is one of the most environmentally hazardous consumer materials ever produced: Vinyl has caused considerable occupational disease and contamination of local environments.
PVC is the antithesis of a green building material.