Water infiltration is one the main problem in the construction industry. They are generally caused by the deterioration of a surface, which consequently loses its waterproofing ability, or by a failure in the waterproofing capacity of the surface. The consequences of water infiltration may be only “aesthetic”, such as the separation and detachment of the painting, the formation of spots and streaks of moisture, mold and efflorescence, or, in severe cases, it can cause real structural problems, accelerating the degenerative process of building materials.
The design and choice of the best solution for waterproofing a surface, therefore, is a key aspect to ensure the maximum possible duration of the buildings, reducing to a minimum the maintenance required.
A first and important distinction between the different types of waterproofing is the intervention in presence of positive thrust and the ones with negative pressure, or counter-thrust.
Waterproofing with positive thrust
This category includes all interventions in which it is possible to operate on the surface directly in contact with the infiltration. This type of intervention is aimed at preventing the absorption of water by the whole structure. Practical examples of this category are: waterproofing of terraces and balconies, roofs, foundation walls before backfilling, liquid containment tanks, tubs, swimming pools.
Waterproofing with negative pressure
This category includes interventions in which you cannot operate on the surface directly in contact with the infiltration, and is therefore necessary to intervene on the surface on which infiltration occurs, blocking the leakage of water or moisture. Examples of this category are: waterproofing of basements and cellars and waterproofing of walls with the ground.
You should always consider that a positive thrust waterproofing allows to preserve the entire structure by absorption of water and its consequences, while the waterproofing with negative pressure can block the escape of water or moisture, but do not prevent the structure absorbing water.
Positive Pressure Waterproofing
The waterproofing positive momentum involves creating a layer of waterproof material and is applied directly on the surface to be sealed , either flat, sloping or vertical . Regardless of the sealing ability of the material required to create sufficient flow for proper water drainage is essential.
Especially in the case of very large areas of intervention, a key feature is undoubtedly the elasticity of the sealing layer to be achieved. An elastic sealing layer will be able to cope with expansion movements without damage or cracks that inevitably will allow water to leak.
Another very important aspect to consider is the sequel to the sealing layers. Traditional technologies based on the use of bituminous membranes, which have many overlaps and joints due to the difficulty of setting and the great damage from the effects of cooling – heating, have major problems disordering connections and water penetration.
The ease of application of a sealant should be linked to: minimize the possibility of error from the installer and the application should be simple and fast, contributing to the success of the end result.
The sealers of positive pressure should be characterized by the ease of use ( by brush or roller ) and the high elasticity of the layer, due to the high amount of resin compared to the cementitious ones. For each application there are corresponding materials in order to have a better and cheaper solution.
Negative Pressure Waterproofing
Often the water penetration can not be solved by acting directly on the surface on which the filtration takes place, but only from the surface where there are the results in the form of spots and streaks of moisture or water penetration as cellars, basements, elevator , walls and floors etc.
The material to be used for sealing negative pressure must have, apart from the sealing ability, very high adhesion to the substrate. The product for sealing negative pressure should create a continuous and uniform layer of sealing. The high adhesion and the easy implementation (with a roller) to permit the use of multiple solutions of thickness up to 5 mm, depending on the needs of the application.
Waterproofing Joints – Cracks
For the success of the seal must ensure waterproofing of critical points such as vertical and horizontal joints, expansion joints and cracks that there is a possibility of water filtration, and therefore should be treated and sealed with the maximum care and attention.
The seal should be strong, durable and have the possibility of easy filling and resistance to ultraviolet rays and weather conditions, by the use of suitable sealing bars and strips (depending on the needs of the application).