Forum Topic

Cellar tanking - recommendation please!

We have water seeping through ... tanking specialist recommendations appreciated!

Emma Elizabeth ● 2130d4 Comments

Is this happening for a reason? Our cellar has been flooded in the past, once when the cover over the stream that runs into the Thames at SOTG railway bridge got stuck open and high tide flooded up, and once as there was a burst water main nearby.

Vivienne Cox ● 2130d

thanks - we have had all external pipes surveyed and had some repair work done - but water still appears after heavy rain - various people have said the tanking has failed and the water table is causing water to seep in

Emma Elizabeth ● 2130d

Some years ago we used a company called Proten based in north London to sort out an existing basement flat that was suffering from water penetration, but there are several basement companies in west London who will do the same kind of work. Rather than patching up the wall covering, the modern way was to install wall and floor membranes that don't try to hold any water back, but allow it to work its way down into sump pumps recessed into the floor which pump it away. All very dramatic when they were doing it, but it seemed to work and made the place habitable again, though this was a residential home and not a storage cellar, which might respond to a simpler approach.

Peter Evans ● 2130d

Has a surveyor had a look?If after heavy rain then unlikely to be water table, as that stays 'fairly' constant.If a 'leak' fairly shortly after rain, then it may be that water is finding its way in from the top - which means external repairs like french drains and flashing, if from 'below' then could be a breach of tanking.2 approachesTry and keep it out - so a waterproof render is used internally and hopes to keep the water out (this is vulnerable to cracking/movement).Or (like another poster stated) you accept that there is going to be water, use an egg crate layer to catch it and move it to a sump pump, and put a 'dry' layer on top of that.Slightly more involved and you lose the wall thickness of the system (25-50mm)But neither of them will solve surface water coming in if that is what it is after a heavy rainfall (and rainfall is getting heavier - not necessarily more of it, but in a shorter period of time).So a surveyor used to water would be a good bet. Talk to them and then ideally call them in shortly after a heavy rain - water is really hard to trace as it tracks through different structures in different ways!

James Holmes-Siedle ● 2129d