Fortifiber has created Fortifiber® Water Tight A1 Window Install for Drainable WRB, a window installation technique specifically for drainable housewrap.
The very channels that make drainable housewrap so effective at directing water away from a structure also pose an incredible challenge when installing windows with the A1 method. In an A1 install, the housewrap is applied before the windows are installed. When using this method with drainable wrap, flashing the windows to achieve a water-tight seal is very difficult.
Those interested in the details can find the installation guide at www.fortifiber.com/pdf/install_guides/IG_weathersmart_drainable.pdf.