The subcontractor performing the refurbishment, Elmgrove Develepoments LTD, have been proposed using a cavity drain membrane with a sump pump system a type C: drained protection following BS8102:2009.
The membrane system installation was lengthy due to the groundwork carried out by Elmgrove Developments LTD; the foundations had to be dug up and poured with concrete because the previous company did not do their job reliably. The contractor also had to pour a new sub-concrete base. Together with the contractor, we decided to install the pump tanks and all the wiring before pouring the new sub-concrete base. Draining the water collected in the tank from behind the membrane was a challenge due to the length of 16 meters that the water had to travel to the nearest drainage point.
The next step was installing the cavity drain membrane system; here, we used three different types of membranes to waterproof the basement; PLATON P8, PLATON P20, and PLATON plaster mesh from Triton Systems. In places where cabinets and other kitchen furniture were to be hung, we used the PLATON P8 membrane, which was installed using a hollow Brick Seal plug that enabled the installation of the partition wall on the membrane, giving a solid fixing for all the units. We installed the PLATON P20 membrane on the subfloor, the subcontractor then insulated the floor with 100mm Kingspan, and the new screed was poured. Any other walls had PLATON plaster mesh installed which then was finished with a dot&dabbed moisture resistant plasterboard.
The sump pumps we used in this project have battery backups. If the primary pump fails, the second pump will automatically turn on. In tanks with pumps, we also used a system of three alarms; this system allows us to react quickly in the event of a failure of one of the pumps, thanks to which it allows us to prevent any flooding of the basement.