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03/13/2009 <br />Page 2 - <br />you have specified, installed in shingle fashion and incorporating all related fiashings, <br />serves as both the air/water barrier and the drainage matlsystem. Finally a new, non-water <br />tight siding system goes on; this could be siding, stucco, brick or other materials. This <br />siding is the new"Banier" layer that sheds the bulk of the water, but no longer needs to be <br />"perfect" because of the primary drainage system below. <br />Next, I want to discuss what effect the windows have on the existing issues. Currently the <br />windows are tied into the existing Barrier system. Any opening in the barrier including <br />cracks, control joints, caulk joints and windows is a potential point for water to enter the <br />wall. If I was asked to replace the windows without removing the existing stucco I would <br />have to add a drainage system under my windows that would channel any moisture <br />entering the window system to the exterior though a direct path. This system is called a <br />"Subsill" (see attached detail). This would ensure that my new windows are not <br />contributing to any future moisture issues. Drainge weeps in this new window system <br />should never be caulked, as the weeps in the existing windows were caulked shut. Please <br />bear in mind, these new windows, with or without the subsill system, will not help with the <br />existing issues of water entering the wall system at the roof, deck connections, vents, <br />cracks in the stucco, caulk joints, or any other penetrations or openings. Window <br />replacement alone is only a partial fix. Also as moisture problems continue over time, <br />these new windows would also be at risk of damage as deterioration of the walls continues. <br />If on the other hand the project is done as currently specified, the Contractor will install the <br />new windows and new drainage path/system, as a complete system, onto the building (See <br />attached). This would not only deal with water that may enter overtime from around the <br />windows but all other possible points of entry. One suggestion, by others, was to cut the <br />stucco back from around the windows and replace the windows, and a limited area of <br />stucco. By doing this three points should be considered. First, the joint between new and <br />existing stucco is an area that would quite likely become a new point for water to enter the <br />wall. Second, the areas not repaired remain an imperfect barrier system that will continue <br />permit water intrusion and cause future deterioration within the wall system. Third, this <br />does not address the existing moisture that is in the wall causing mold at best, and <br />deterioration of the structural wood framing at worst. <br />The above information is based on my understanding of basic building science, and not <br />part of an Official Pella Recommendation. We would prefer to perform the window work <br />as originally specified, however if you would like to proceed in a different manner, we <br />would be happy to provide a new quote with the addition of the required window sub-sill <br />system. <br />I hope this information is useful and please give me a call if you have any additional <br />questions. Thank you, <br />Dan Headley <br />Pella Commercial <br />Senior Commercial Project Specialist <br />612-501-9169 <br />