The terrace is the building element where the layer sequence is most frequently confused. In the widely used inverted build-up, the layers from bottom to top are: the sloped structural slab, the waterproofing, a polyethylene sheet as the separation layer, the thermal insulation, a heat-treated geotextile felt (at least 300 g/m²) and, on top, a sloped protection screed with joints. A conventional (warm) build-up, with the insulation below the waterproofing, is also a valid system — but only when designed with a vapour control layer. Problems start when the two systems are mixed.
The second critical issue is falls. Falls should preferably be formed below the waterproofing, in the structural slab. Water must be able to reach the drain; the direction and gradient of the fall must be correct. The drain is set in epoxy grout mortar and the waterproofing layer is joined continuously to the drain flange. If this junction is wrong, the terrace will leak regardless of how well the rest of it is done.
The building is visited in person. Neither diagnosis nor solution is discussed before this step is complete.
Findings, cause and required work are put in writing: which product, which thickness, in which sequence, with which detail.
What is to be applied to which surface, how many square metres, which materials and the cost of each item are made clearly visible.
Where required, the consultant is present on site; critical details are checked before they are covered and non-conformances are reported in writing.
When the request form is completed with location and scope, the enquiry arrives with the context needed to give a direct response.
