Negative waterproofing in concrete curtains

The simple and rigid obstructions characteristic of negative waterproofing don´t consist of solutions, but palliatives: the water, via capillary and/or micro-cracks in the structure, looks for new paths. And not only that: the reinforcement of concrete will be at the mercy of oxidation, which inevitably will imperil the structural stability over time.

The conventional methods of exposure on the outer side of a curtain, by an excavation for corrections and subsequent filling, are usually very expensive and traumatic especially in the case of inhabited buildings. And, the adhesion of a new membrane over the former is always in deficit when the original waterproofing is done with any type of flexible membranes, a fact that in most cases requires a general re- waterproof of the curtain.

In recent years, many chemical industries in the field, worldwide, have studied coherent solutions for this issue. The approach has been the filling of the capillaries in the concrete, in the opposite direction to the flow of water through osmosis. And it works: in some cases more, in other less. So, the procedures described in the preceding paragraph, in most cases, are eliminated.

Rising damp

Arch-tec developed its own technology to eliminate the problem, a system denominated “deep drainage”. But the matter requires a prior analysis in each case, according to each project of architecture, building materials taken, the topography and rainfall. These variables are vital for the design of each system.

The grout of the perimeter walls is the first to suffer damage on both sides, continuing its way to the grout of the interior walls and even internal floors of the building.

Surface drainage systems, with perforated pipes, are not efficient in these cases.

The problem is exacerbated in regions where the water table rises, and even flourishes, in periods of rain.

This technology consists of a mixture of surface drainage with partial waterproofing of the external grout and the deep drainage itself, as canals molded in the same field, with shafts in their bases (relative sections, diameters and depths that can be calculated with the variables mentioned above), and crushed stone filling and appropriate felt.