How can I seal DensGlass (exterior drywall)?
beichenlaub
| Posted in Energy Efficiency and Durability on
I am using DensGlass on the exterior of my home (urban infill lot with zero clearance). I will be wrapping the exterior with Tyvek. I am thinking of sealing the joints of the DensGlass also. Is this overkill? What should I use to seal the DensGlass?
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I'm sure you are aware DenseGlass is typically a commercially used product. You need to go to GP DenseGlass webpage and download all the documents pertaining warranty and installation when applied as moisture and/or air barrier, and depending on the cladding you are using. Also, it is not a structural sheathing, so you must install bracing according to the IRC.
Charles,
Here is the document you are looking for: Technical Guide: DensGlass sheathing.
Check the section titled "Air- and Water-Resistive Barriers." The guide notes:
"In areas that do not prescribe to current code requirements but still require long-term joint protection, either of the following two methods may be specified in lieu of an air- and water-resistive barrier system: Method 1) Apply minimum 3/8” (9 mm) bead of sealant to joints and trowel to provide a layer approximately 2” (51 mm) wide by 1/16” (2 mm) thick spanning the joint. Use backer rod for openings larger than 1/8” (3 mm). Method 2) Apply glass mesh joint tape to all joints, overlapping at intersections by the width of the tape. Apply approximately 3/8” (9 mm) bead of caulk along the joint. Embed the caulk into the entire surface of the tape with a trowel. Use backer rod for openings larger than 1/8” (3 mm). Follow manufacturer’s installation recommendations for use with DensGlass Sheathing, and design authority specifications. A variety of caulk and polymer-based “fill” materials may be specified, including GE, Dow Corning, Tremco, Sto, Dryvit, BASF and Proseco. Please contact the caulk manufacturer for its recommended caulks over DensGlass Sheathing."