[RE-wrenches] Flashings versus Sealants

[Tom Lane]

Education time , Sikaflex is NOT recommended by the manufacturer to use on asphalt shingle roofs , no polyurethanes are recommended for asphaltic materials and they are not rated above 170 F . Likewise  no silicone sealants should be use as they DO NOT STAY ELASTOMERIC . PLEASE read the product specifications of the materials you are using . They must stay elastomeric from 40 F below zero to 200 F or they are not acceptable . Rubber butyl nitrile like Ruscoe www.ruscoe.com are the only type of sealants that have UV resistance and stay elastomeric and are rated from 40 F below zero to 200 F . Do not argue against the product specifications on the product data sheets . All L feet and flashings should use a sealant , if you think you can use flashings without a sealant -  GOOD LUCK  - you will need it on a rain pouring down a roof with a hard rain blowing up the roof . Your job is only to stop leaks and keep high winds from blowing the PV modules , solar hot water collectors , or pool collectors off the roof . You do not create the solar electric energy or the thermal power . The roofing work is solely to install the product to code and under the PRODUCT SPECIFICATIONS of the roof materials you are using to prevent damage to the roof and the contents below . Stop using urethane sealants and silicone sealants period in harsh environments on this planet where they are not specified by the manufacturer on the product data sheets would be a beginning . Only lead or copper , aluminum , marine grade stainless steel flashings for piping will last for 100 years . Aluminum and copper flashings must be used with the appropriate materials . Metal roofs sometimes require EDPM rubber flashings for pipe penetrations ,BUT , it must be protected from direct UV light to last 100 years . Gator Tom PS : sealants should be under the 
L feet or U channels or flashings on the roof AND over the top of the lag bolts , j or hook bolt , or all thread rod bolts nuts . 


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