Vapor-Retarding Membranes for Back-Up Walls Sacramento CA

Applying a rubberized asphalt membrane over the surface of the concrete masonry would make a more effective vapor-retarding membrane than would an application of an asphaltic paint in Sacramento.

Ul Chimney
(916) 429-6650
372 Florin Rd 297
Elk Grove, CA
 
Elk Grove Granite
(916) 714-7887
9914 Kent St
Elk Grove, CA
 
Ovels Masonry
(916) 879-0515
8576 Ferncrest Way
Elk Grove, CA
 
Conner Plastering
(916) 786-4729
497 Diamond Bar Ln
Roseville, CA
 
Arletis Plastering
(916) 870-8094
9443 Marius Way
Roseville, CA
 
Asims Tile Stone
(916) 714-4855
9090 Union Park Way
Elk Grove, CA
 
Sac Plaster and Design Inc
(916) 685-7379
9370 Winding River Way
Elk Grove, CA
 
Nor Cal Masonry
(916) 781-2777
1316 Church St
Roseville, CA
 
Coating Specialties Co
(916) 773-7799
2200 Misty Hollow Dr
Roseville, CA
 
Curtis & Curtis Tile Co
(916) 771-2200
721 Arabesque Cir
Roseville, CA
 

Vapor-Retarding Membranes for Back-Up Walls

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Source: MASONRY CONSTRUCTION MAGAZINE
Publication date: November 1, 1999

I have heard people recommending asphalt coatings for the exterior face of the concrete masonry back-up wall in cavity wall construction to act as a vapor-retarding membrane. This is particularly true with an exterior wythe of glazed brick. If the intent is to create a vapor-retarding membrane on the surface of the block, wouldn't it be better to use an impervious sheet membrane, such as rubberized asphalt? The surface of the concrete masonry is typically very rough, and an asphalt coating would typically contain pinholes.

Applying a rubberized asphalt membrane over the surface of the concrete masonry would make a more effective vapor-retarding membrane than would an application of an asphaltic paint. However, before applying any coating, you must ask yourself whether this is the proper place for a vapor-retarding membrane. A vapor-retarding membrane should be on the warm side of the insulation. Therefore, over a large portion of the United States, the heating season dictates that the vapor barrier be on the interior side of the insulation. For insulated cavity walls, this would be the exterior surface of the concrete masonry backup wythe. However, when insulation is not placed in the cavity, it would typically be either within the cells of the masonry backup or on the interior surface of the concrete masonry.

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