Tanking a Cellar

Cellars are damp and can become unstable for storage/ usage and these areas are susceptible and prone to damp issues

The whole area will need to be cleaned and dried out the best possible, if external tanking cannot be achieved then internal tanking is achievable. Damp walls in a cellar are common because the walls are below ground, the walls surrounding the building have earth in them and they can retain a lot of water and this can make its way into the cellar.

A tanking slurry will need to be applied to the walls this will stop the tracking of moisture and sometimes salts and minerals making its way into the basement. The tanking of slurry is a mortar mix and has chemical modifiers, these additives improve the bonding and strength, holding the product together. All surfaces need to be prepared any loose mortar or plaster should be ‘hacked off’. A salt inhibiter is recommended this stops the migration that could affect the waterproofing. Once prepared mix the slurry powder and coat the walls in 2no passes the 2nd 24hours within the first coat application. Once this has cured, we need to apply the liquid coating system. Some of these come as a single component such as Riw, or liquid rubber and other modern coating systems are applied, even mastic asphalt can be applied on smaller projects.

On the cellar floor, this also needs to be tanked, this is coated after the walls have been lined. The same methods are applied and reverse coating the areas are applied with a 75mm to 100mm overlap achieved at all vertical junctions.

Once this has been allowed to cure for at least 24hours, the floor screed tiles etc can be applied. As for the walls a plasterboard or multi-finish plaster should be applied and never paint straight onto the liquid coating.