When you start thinking about installing an attached system, you should evaluate the site conditions for any unusual or specialized conditions, before beginning any roofing, inspect the site conditions that might affect the productivity or present any problems in the duration of the job.
Inspect the building structure to make sure the building structure is capable of carrying the weight of a new roofing system. Verify the adequate slope to drain conditions making sure there is positive drainage. Add new drains where needed to eliminate any ponding, which can lead to membrane damage and possible roof collapse.
Correct all the defects in the deck, replacing any damaged decking or substrate that can lessen the overall roof performance. In order to install a roofing system that will perform properly, the deck or substrate must be clean, dry, sound, and smooth. Prepare for the new roof installation properly, new roofs will have fewer problems and perform longer if the proper preparations are done. Use this guideline, Remove all of the existing roofing materials unless they are to remain and are in good condition, Also, remove wet or damaged insulation to ensure a good roof installation and to avoid interior damage.
Clean the substrate surfaces cleaning these substrates will get rid of any contaminates. If you are leaving the existing roof in place, remove any blisters and ridges to provide a smooth surface. Cut the existing membrane away from the penetrations and perimeters, this will allow the new membrane to expand and contract independently of existing membrane. Inspect the substrate conditions, perform a fastener pull out test and moisture surveys if needed or required to determine substrate conditions.
Confirm equipment support heights, these must be minimum 8″ to allow proper flashing heights. Raise the flashing height as needed, and flashings that are lower than 8″ have increased potential for any moisture intrusion in the roof system from rain and snow.
Wood nailers are usually 2 x 4′ or larger that are used to connect the roof system components to the structure. Install these wood nailers around roof perimeters and penetrations where needed. Some penetrations such as HVAC curbs may not require wood nailers if they already have a structural system. Properly installed wood nailers must be wood, #2 grade or better, nominal 5/4″ x 4″ minimum, are staggered when multiple layers are required for greater stability, they must be able to resist 250lbs. force in any direction and have 3 anchors per length minimum.