proper overhang of capping mateials, and.flashing at all penetrations, terminations and transitions, integrated with the WRB and water directed out of the system,.Other checkpoints for effective water management include: When a system of this type is used, some building codes permit the use of a single WRB. (5 mm) and a maximum drainage gap of ¾ in. These systems have a minimum drainage gap of 3/ 16 in. The outer layer of WRB is intended to keep the scratch coat from contacting the inner layer of WRB and may be of a different material than the inner WRB.ĭrainage Wall Systems: Drainage wall systems also are a very effective means of keeping water from penetrating to the interior and diverting it to the exterior. The WRB should be installed in accordance with the manufacturer’s recommendations and be integrated with all flashing accessories, adjacent WRBs, doors, windows, penetrations, and cladding transitions. (406 mm) past the corner in both directions. Inside and outside corners must be overlapped a minimum of 16 in. The vertical joints of the WRB must be lapped a minimum of 6 in. The upper layer of the WRB should lap the top of the lower layer by a minimum of 2 in. Starting from the bottom of the wall, the inner layer of WRB should be installed, along with flashings, to create a drainage plane. The standard also requires that the two separate layers be installed in shingle fashion. 3) requires two separate layers of water-resistive barrier (WRB) to be installed over wood sheathing in exterior applications. Do not bond manufactured stone masonry veneer to clay masonry surfaces.ĪSTM C1780, Standard Practice for Installation Methods for Adhered Manufactured Stone Masonry Veneer, (ref. If a bondable surface cannot be achieved, attach lath and a scratch coat before installing manufactured stone veneer. Typically, cleaning may be done with power washing and/or mechanical methods (i.e. An ICRI CSP equal to or greater than 2 is usually acceptable. 5) discusses Concrete Surface Profile (CSP), a standardized method to measure concrete surface roughness. They must have a rough texture to ensure a mortar bond. Manufactured stone veneer can be directly applied to surfaces of concrete and concrete masonry if they are free of dirt, waterproofing, paint, form oil, or any other substance that could inhibit the mortar bond. 11) limits the deflection of wall systems to L/240 for brittle finishes. Also note that the International Building Code (ref. Additionally, the wood framing should be relatively dry at the time of installation, as drying of the wet substrate causes shrinkage which could lead to cracking of the finish. This will allow water entry and degradation of the substrate, the veneer and the framing. Without the gap, wood swelling will cause the adhered masonry veneer finish to crack, compromising the water resistance of the finish. (3 mm) gap between the sheets on all sides to accommodate wood sheathing expansion when it gets wet. 1), when wood structural panel sheathing (plywood or oriented strand board – OSB) is used as the substrate material, it must have a ⅛ in. Substrate PreparationĪccording to The Engineered Wood Association’s (APA) Installation of Stucco Exterior Over Wood Structural Panel Wall Sheathing (ref.
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