LONDON'S #1 BASEMENT WATERPROOFING EXPERT

Before we tank your basement, we need to determine the correct tanking method, or if you need tanking at all.

We start with one of our qualified surveyors visiting the site to take a series of readings with moisture meters along with a visual inspection of the damp to determine the best method for waterproofing your underground space.

Damp comes in many forms, one of the most common being condensation. If your walls are wet and mouldy but no groundwater is coming through the walls, then your problem is more likely to be poor ventilation – which tanking won’t fix.

If the damp is caused by groundwater seeping through your walls or floor, we have two methods to waterproof your basement: Type A and Type C.

Type A tanking involves applying slurries and membranes over the walls, on top of which we apply fresh paint and plaster. This system will completely waterproof your walls up to eight bars of water pressure.

When we believe the water pressure will exceed what can be safely prevented with a Type A tanking system, we will install Type C.

A Type C tanking system creates a void all the way around your property. Blocked groundwater collects in this void and drains into a gully, where it’s pumped out by a sump pump to join the rest of your wastewater drainage.

Type C tanking systems are more common in areas with very high groundwater levels, such as Fulham, Putney and other Thames-side locations.

While we will always try to provide an accurate quote following our damp survey, sometimes we won’t know which tanking method is appropriate until we strip back the plaster and examine the wall beneath – known as a destructive survey.

There is an extra charge for a destructive survey so we only carry them out as a last resort where meter readings and visual inspection give us inconclusive results.

Whether we use a Type A or a Type C tanking system, we always fully strip away damp materials first, allow the underlying wall to dry out and fill in any cracks that are allowing water inside.

We then apply a four coat system using slurries and membranes from Sika, Delta and Sovereign, three of the world’s leading manufacturers of damp proofing products. Which we use depends on the individual requirements of the site.

Beware quotes that promise a quick fix – tanking needs to be done slowly and carefully with correct drying times between each layer and regular moisture meter readings to ensure the tanking is effective.

Don’t trust cowboys to keep your basement safe, call Environ now for a guaranteed tanking solution

Unfortunately, many of our tanking jobs involved replacing shoddy damp-proofing works installed by cowboy contractors.

For example, certain tanking slurries won’t stick to certain surfaces – a common problem with period masonry. Apply the wrong slurry and, over time, it will simply crumble away from the wall.

We’ve also visited basements where a Type A tanking system was applied when Type C was necessary, causing the water pressure to build up behind the seal until the whole thing was blown off.

Worst of all, many tanking systems are applied without stripping away damp plaster or repairing the wall beneath. Without fail, these shoddy attempts to quickly cover up the problem rather than solve it only lead to more expensive repairs down the line.