A Cavity Drain Membrane system is used on the internal face with the earth retaining structure where it can accept the ingress with water depressurise it and manage it to a safe evacuation point. This is known as type C form with basement waterproofing.

Tanking as some sort of basement waterproofing to brand-new structures has inherent risks. Whether you apply it internally or externally to your structure tanking systems need to be applied 100% defect free to be affective, if water is delivered pressurized against the structure. As dispute and High Court case between several companies Outwing Construction and Thomas Weatherald has set a precedent inside basement waterproofing industry together with UK law. The ruling in the High Court of Justice was that it is not reasonable for some sort of tanking or waterproofing system to become applied 100% defect absolutely free. What this means is that when you design for or apply a basement waterproofing system to your structure which has to be 100% free of defects to figure and it fails you will be liable for the consequences of that failure. By their very nature all tanking systems ought to be 100% defect free to work when tested by water pressurized from the ground.

Most new build basement waterproofing designs that incorporate an external tanking system add a land drain the purpose of which is to help de-water the encompassing ground areas and reduce the level of water which is delivered against the structure. There are often many associated problems with land drains used in basement waterproofing. A land drain should be positioned on the exterior of the structure below the amount of the internal slab in order that it helps to relieve the volume of water fully depth of the maintained soil. Many times the position of the land drain is shown on a drawing or installed above the internal slab level and consequently could only ever end up partially effective.

‘The mode and feasibility of remedial treatment’ can be a buzz phrase in that basement waterproofing industry. It means if you will find there’s problem with the ability to get back to something to identify where and what help and then rectify it. This is a problem with both external tanking and land drains as they are generally buried under tonnes of earth. The size of this land drain is another issue as that can accurately predict the volume of water which could be expected to come to have everytime in the future? Also as stated the tanking system may rely heavily in the land drain and how can anyone guarantee it with defect or blockage when you need it – again the form and feasibility of remedial treatment makes question.

The BS8102: 2009 (British Standard code of practice for protection of below ground structures against water from the ground) recommends a maintainable basement waterproofing system. A buried external tanking system and land drain may not be easily often maintainable.

Building a very good basement structure to form the main resistance against water is a good idea but where there are construction joints should expect that water ingress could occur certain times. Therefore a more reliable version of secondary waterproofing other than the structure itself is some sort of cavity drain membrane process or Type C underground room waterproofing. basement waterproofing chicagoOne of the challenges of numerous homeowners is basement waterproofing.