Overview
The roof area consists of a main flat roof to the building and then a newer extension has been built upon this . The main roof is formed of a concrete deck and is finished with a reinforced bitumen membrane ( RBM ). In several areas this has had an additional covering of a PMMA ( polymethyl-methacrylate ) overlay . A more recent extension has been added that consists of fibre glass cladding with RBM flat roof areas that have been overlaid with PMMA . These roof areas are divided into 2 areas with one covered in plant and mechanical equipment making access very difficult . The areas are reached by individual wall mounted ladders , some of these appear to have rusted bolts .
Higher roof 1 Approximately 4m wide and 28m long the flat roof section is a felt membrane what has been overlaid with a PMMA . This has a few areas of damage but does not appear to have penetrated through to the felt . Several areas of the roof have signs of recent repairs with a liquid polymer on the laps and around the scupper in the upstand . The roof has a preformed glass fibre dormer made up in approximately 1m sections which are overlapped . The overlap is then covered in a mastic / sealant . This has perished or shrunk and no longer effectively seals the gap . The drainage channels on the top of the dormers are blocked in several places and a large amount of water ponds on these areas . Drainage on the flat roof section is provided by a scupper outlet through the upstand at each end of the roof to a hopper with an external goods pipe . Large amounts of debris have blocked the scuppers and this has created large areas of ponding . The windows in the dormer are outwards opening aluminium rooflights , the drainage channels around the frames are full of debris and need clearing , the paint is peeling off the frames leaving the bare metal exposed , some of the windows have not been closed properly from the inside .
© Building Transformation 2022
Recommendations
The debris on the roof should be removed along with the vegetation . The holes in the PMMA should be cleaned and sealed with a suitable PMMA system ( this should be adhesion tested before the repairs are carried out ). The scuppers through the outlet and the hoppers should be cleaned and lined . All the debris should be removed from the dormer roof flat sections and the mastic sealant raked out , the joint cleaned and resealed . All the windows in the dormer should have the drainage channels cleared and then be tested to make sure they close properly . The aluminium frames should be cleaned and repainted . Any cracks in the fibre glass dormer should be filled and sealed .