Tanking

Conversion of Cellars, Vaults and Basements

Many basements will be damp, either due to penetration of moisture, or to condensation. Dampness and associated condensation can result in an environment in which mould and fungal growth can flourish. The conversion and improvement of basement areas makes effective use of a part of the building which might be wasted and unoccupied, and if not adequately waterproofed, may be unfit for human habitation. Conversion of these areas to habitable standards can present difficulties, with the possibility of structural movement, low ceiling heights, absence of natural lighting and poor ventilation. Where a conversion is under consideration, the suitability of the proposed scheme should be discussed with the Local Authority, particularly when the building is listed as being historic or of architectural interest and to ensure compliance with local planning and Building Regulations. Limitations of the original design specification or poor site workmanship may result in leakage problems either shortly after completion or at a subsequent date, which can be many years later due to a rise in ground-water levels, changes to the surrounding sub-soil, or alterations to the structure itself or to adjacent buildings. Almost all below-ground areas are likely to be subjected to water pressure at some period of their life. Even if the ground-water table remains constant, water mains or sewers can burst, resulting in serious water infiltration to unprotected areas below ground.

Investigation and Survey

A preliminary site investigation is essential before submitting any proposal to waterproof a cellar. Knowledge must be obtained of the type of construction, any existing waterproofing treatments and the client's intended use of the basement area. The existing or intended ventilation/heating arrangements must be established. Also the possibility of contamination of the substrate by ground-water, since in the U.K., high levels of chlorides, sulphates and nitrates can occur. Sulphates may also be present in certain types of brick or be impregnated into walls -  for example in coal cellars. To overcome the aggressive effects of these elements, special cements or chemical impregnators may be required. The original construction materials will be examined as far as possible from a visual survey. Floors in domestic basements and cellars are invariably of brick or stone construction and often an existing solid floor will not incorporate a damp-proof membrane. On completion of the survey, a sketch diagram can be produced, indicating the areas to be treated and this will, where appropriate, accompany a detailed, priced specification, scheduling the proposed work.

Although in the majority of situations Sika-1 Waterproofing System has been found to satisfy most requirements, alternative standards of performance for waterproofing may be required and consequently various waterproofing specifications are available, from the company to meet each need.