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Basement Damp Proofing Tanking Specialists in London

If you’re building beneath the ground or converting your basement, coal chute or cellar to into a liveable or useable space, you need tanking – a seal which stops pressurised groundwater seeping through your walls or floors.

Without tanking – or if tanking is done poorly – your basement or underground stores will become damp, leading to structural weakness, property damage and mould.

At Environ Property Services, we provide a high quality tanking service guaranteed to keep your basement bone-dry for 15-25 years.

Need tanking in London? Call now to book your survey and tanking quote

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.

Call Environ now to get in touch with our damp experts

Our friendly team of qualified and experienced damp experts take pride in keeping London’s homes and businesses dry, safe and comfortable.

To book your survey, call us now or request a call back today.

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I wanted to take a minute and thank you all for resolving the damp issue we had. Its so nice to come home and not see or smell the disaster that was there before. Just in time for Christmas which I would have to say you guys saved as we have family coming who had their flights already booked. A massive relief Thank you so much!! Would definitely recommend your team from initial contact to works completed. Great job.
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I chose to use Environ to deal with a damp wall, the whole process from beginning to end has been straightforward, well explained and they've managed to strike a pleasing balance between friendliness and professionalism. Everyone they sent over during the course of the work, as well as their office staff has been, nice helpful and accommodating. I hope not to need to use them again but if I do, I'll do so gladly!
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Came round to have a look at work required and actually realised it was all low level work. Explained and showed what was required. They can back about a week later (or thereabouts) to carry out the work which was done very quickly (about an hour if I recall). Because it took less time than was originally thought have not been charged for the materials so was very happy about that.

Ryan R.


Kristian F.


Jacqueline M.