Problems Associated With Flat Roofs and Roofs Terraces
You will often inherit a flat roof and roof terraces when purchasing a property, as they are a common design feature here in Spain.
Upper terraces are often structurally sound, it is unusual for them to be built as an afterthought. Although I have come across instances where this is the case, where they are separating from the main building. However, flat roof and terraces can still be a cause for concern and costly to put the faults right.
The main problem associated with flat roofs and terraces is water ingress. The main structure of Spanish properties is reinforced concrete. The builder will often skip the very important phase of preparation, which involves sealing the concrete from water penetration, by simply laying the tiles onto the concrete.
Due to the extreme variations in temperature the tiles will expand and contract with the result that the grouting after a few years will start to degrade and water will find it’s way below. The concrete will absorb the water and travel along the beams into the living space below, causing the ceiling plaster to blow, separate and crack.
Invariably, drainage is poorly thought through. The very heavy downpours, experienced here in Spain, will cause damage as the water cannot escape fast enough due to vegetation blocking drains or the water pooling as the runoff is insufficient.
Often, there is no drip ledge on the terrace tiles so the water runs down the walls and is absorbed by the plaster as it cascades down the sides of the property, causing moss to grow on the outer walls, scaring the building. The terracotta bricks, that all Spanish houses are constructed of are extremely porous and so, over the winter months, they will hold the water causing fungus to form on the interior of the properties.
Solutions
Simply tiling over the old tiles will not resolve these issues. The only longterm solution is to remove the old tiles, screed the flat roof or roof terrace and seal the concrete, using a roof membrane. The correct laying of the impermeable membrane is crucial to the longterm life of the terrace or flat roof.
The tiles can then be laid in the safe knowledge that the roof will be impermeable to water ingress.
A thorough understanding of a proper drainage system prior to the laying of the tiles is needed.
Contact us at LT Construction for all of your roof terrace and flat roof concerns and issues, contact the experts at LT Construction.