Commonly ‘weber.tec hydrostop’ or ‘Sikafill’ paints are used for recovering, however there is a better material available ‘Sikafloor 400N Elastic’ which is designed to seal the roof terrace, while being more resilient to foot traffic. In the short term, a secondary membrane can be added over the existing tiles in the form of a roof paint, which is best reinforced with a polyester mesh. Sika do however now make a tile red coloured version ‘Sika Sealcolor, rojo teja’. While leak areas are commonly flashed with bitumen backed foil, this too will fail over time and often only serves as a temporary and often unsightly solution. Despite the strong nature of SRC beam roofs, they will actually flex slightly under loading, and hence years of BBQ’s and sunbathing on the terrace will also aggravate the surface and membrane. The roof is also prone to heave above load bearing walls, which can also result in membrane failure. Movement and membrane failure will also commonly occur at parapet wall junctions, chimney stack junctions and level changes. A risk of shorting and even electrocution can occur if electrical installations become wet. ![]() This will normally cause more extensive ingress. Poor laying or bowing of the roof can also create pooling areas. Ceilings will become stained or later risk collapse, the SRC beams will start to decay and rainy days may call for a few strategically placed buckets. ![]() As some tiles start to lose their key, water will be more able to pass across the membrane.ĥ.) Water ingress Once water gets to the failing membrane, it will soon track through to the living space. Point loads such as water tanks can also cause problems. Regular movement will cause fatigue along the movement lines and eventually break though the asphalt.Ĥ.) Surface decay While the membrane tires over the years, foot traffic and weathering will also break down the water resistant surfacing of the tiles and the cracked joints will allow for passage of water directly to the membrane. This causes regular stresses on asphalt the membrane and tile joints above.Ģ.) Surface cracking The tile joints and even the tiles themselves will quickly give in to the movement (sometimes within the first season, or following an exceptionally hot summer or very cold winter) and hairline cracks will appear.ģ.) Membrane cracking Initially the asphalt membrane will be more flexible and hence, more tolerant to some minor movement, but over the years it becomes brittle as compounds evaporate out from the material. ![]() The sequence of failure is normally as follows:ġ.) Thermal movement Extremes between winter and summer, day and night, create expansion and contraction in the concrete beams and slab, (steel beams will be even more prone to movement). While thermal movement is one of the most common causes, the earlier use of less advanced materials helps to accelerate the failure process. Initially this type of roof is normally effective at keeping the rain out for many years, but after 10 years (sometimes earlier) a number of problems can begin to arise.
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