Regarding indoor areas with high humidity: Yes often you can, with the proper preparation. Generally high humidity areas raise the concern of increased risk of mold and mildew growth. Dreamscape products are formulated to resist mold and mildew growth, however when used on a wall surface that has continued moisture problems in the wall cavity, the potential of growth increases significantly.
If the moisture is present in the room, such as a pool, shower, sauna, and you want to prevent it from moving into the wall cavity - we suggest using our Type II fabric backed wallcoverings as barrier. Read more on this here.
If you are concerned about moisture behind the wallcovering, or in the wall cavity, it may be best to use a wallcovering product that allows the moisture to move freely ( breathable) - We generally recommend several options for mitigating the potential of mold and mildew growth, such as our PERFect (micro vented material), using a porous material like Terralon, Terralon Regatta or Terralon Smooth, and choosing a wall primer and adhesive system which have antimicrobial additives. These options are covered in a separate article linked below.
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Please read the article above for instructions on how to best prepare for moist environments.
Regarding installing Dreamscape outside: Dreamscape was developed and tested to be used in interior locations. We have never tested it for long term exposure to outdoor conditions. We do not recommend any installation that puts the product in direct contact with the elements - for example direct exposure to rain. There are some architectural scenarios with partial exposure to the outside where we have heard of our product being used successfully, however we reiterate that there exists no long term data to share and therefore an install like this would be working outside the scope of our product warranties. Examples of partial exposure would be a cabana, pool house, or room with 1 open wall. In each of these cases the wallcovering was covered by a ceiling and therefore did not get direct sun or rain. Also these partial exposure cases were in relatively mild climates - no extreme heats or colds.
It is impossible for Dreamscape or any wallcovering company to guarantee results when it comes to mold and mildew. If you have unusual humid conditions in the room, or in the wall cavity, you should consult with a moisture control expert.