If you have ever tried to maintain a handful of water you will know that it is a very difficult thing to do as even the smallest crack in your grip will allow the water to seep through. If you ran over to your nearest tap and turn the knob to the furthest point, you can imagine that maintaining the handful of water would be near impossible. This concept is almost exactly the same through all solid structures in that water will escape through the smallest holes and the higher the pressure of the water, the more water will leave. However, this implies that the water will always be moving out of its container when in actual fact, it obviously can leak into structures (as many of you will remember the shocking images of floods higher than cars in places such as Devon and Cornwall in the early months of 2014).
Water can be contained in a wide variety of places for a wide range of uses; sewage pipes contain fast moving water and swimming pools often contain still moving water. For whatever reason that a water is stored, water loss or water ingress into is a common problem for many structures. Although you wouldn’t expect it, there are a range of different forces which can lead to the formation of cracks, these include stress movement, settlement, vibration and frequently poor initial construction.
Leak stopping chemical groups are put into place using a single and twin component with a mechanically operated or hand operated injection pump; these resins can be used to control all rates of water flows. Depending on the surface which the leak has occurred, there are three different materials which have been developed for this process:
1. Epoxy resin is particularly useful in wider cracks that have formed in soffits and walls. This resin is extremely advantageous as a structural repair can be produced.
2. Polyurethane resins are useful for injection of wet cracks in slabs, soffits and walls – provided that the cracks are larger than 0.2mm in width. Upon contact with water, this resin begins to foam and produces a resilient, flexible seal. Since these reins are available in a range of viscosities, polyurethane resins can be used to fight low- and high-volume leakage with equal success.
3. Water-based acrylic resin is most effective when it is used for the injection of extremely fine cracks. This resin has a low viscosity and is therefore able to attain a high degree of penetration. Water-based acrylic resin is suitable for injection of wet cracks in slabs, soffits and walls if the crack is less than 0.3mm in width. This resin mixes with any water that is present in the cracks and incorporates this water in the cured product of flexible gel.