CLT: Pre-fabrication Sequences

The interface where the window system meets the CLT panel is important as it can be a common source for water leakage if not designed and constructed appropriately.

Appropriate detailing to provide continuous protection against water and air leakage requires that the WRB is flashed into the rough opening and a continuous air and water seal (typically a backer rod and sealant joint) is provided around the window perimeter.

Best practice in some markets may dictate a metal back dam angle at the rough opening sill to form a sill pan. This angle may also serve as the structural attachment point for the window sill to avoid fastener penetrations down through the rough opening sill.

11 SINGLE PANEL PRESTRIP 1web

11 SINGLE PANEL PRESTRIP 2web

Step 1

Pre-applied strip of WrapShield SA or RevealShield SA wraps onto the underside of the panel for its full depth to cover all wood end-grain and minimum 9 inches (229 mm) onto the face of the panel.

Step 2

WrapShield SA or RevealShield SA sill piece applied directly to the CLT panel and installed into the rought opening to the depth of the air and water seal for the window system.

03A WINDOW RO TREATMENT 2web 03A WINDOW RO TREATMENT 4web

Step 3

1. Jamb pieces applied directly to the CLT panel and installed into the rough opening to the depth of the air and water seal for the window system. Maintain minimum 3” (76 mm) material laps.

2. Head piece applied directly to the CLT panel and installed into the rough opening to the depth of the planned primary air and water seal for the window system.

Step 4

1. Prepare the rough opening with Vapro-SS Flashing applied to the sill membrane per Step 5 and 6.

2. VaproLiqui-Flash or VaproBond at the jamb and head conditions per step 7.

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Step 5

Vapro-SS Flashing at sill 1” (25 mm) down onto the face of the wall. Vapro-SS Flashing to extend up the back dam angle. Fold end tabs minimum 3” (76 mm) up jamb and notch around the back dam angle.

Step 6

Vapro-SS Flashing at sill-to-jamb corners into the rough opening to the depth of theair and water seal for the window system and 1”(25 mm) onto the face. Corner pieces extend upjambs a minimum of 6” (152 mm) and are notchedtight around back dam angle.

Step 7

VaproLiqui-Flash or VaproBond ½” (13mm) tooled fillet bead at seams, including back dam angle to jamb interface. VaproLiqui-Flash at head and jambs, minimum 1” (25 mm) onto face, 3” (76 mm) onto the Vapro-SS Flashing corners, and 1” (25 mm) directly onto the CLT inside the rough opening. 

 

VaproShield Membranes Offer Solutions

VaproShield’s sheet membranes are highly vapor permeable, simultaneously managing bulk water while allowing for some drying of underlying materials.

WoodMetalDiagram

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CLT Design Guide

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Wall Details

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Roof Details

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Prefabrication