The property required internal cavity drainage membrane (CDM) applying to walls and floor, along with associated drainage & pumping, along with external deck waterproofing to allow for an external patio area that would cover the basement.

The principal challenge to waterproofing a basement with a deck is continuity between waterproofing for the deck above and the system for the basement itself. This has to be carefully designed before the build begins and implemented accurately.

Cavity drainage membrane being installed to external wallsWaterproofing carried out in sequence with the overall buildChanging levels throughoutFlooring membrane applied before screed floringSwimming poolAll areas need to be cleaned before waterproofing works can be carried outChange in levels for swimming poolLarge basement with spa complexAll membranes are taped and sealedPerimeter channel at the wall-floor junctionInternal walls isolated from damp by cavity membranesPerimeter channel under internal walls to allow continuityVertical joints are lapped to allow water to flow via gravityPerimeter channels at the wall-floor junction of all external wallsWaterproofing in the plant room for the swimming pool. Floor membrane already installedSump pits cast into the floorWall membrane and floor membrane meeting at a change in flooring levelsComplex shapes at the change in levelsFlooring membraneFlooring membrane taped and sealedFlooring membrane taped to a damp proof course to prevent rising damp issuesDoorways for external patioCavity drainange membrane to external walls and floorFlushing points installed in perimeter channel to allow maintenanceElectrical cables feeding pumps & alarmsFlushing pointWalls and floor sealed, channeling water to sump pitsMaintenance flushing pointPipes and services installed on top of the wall membraneInternal corners with continuous membranesPerimeter channel following the layout of the basementMembranes following the contours of the pools etcCables feeing pumps & alarmsComplex shapes being waterproofedDeck is cleaned thoroughly prior to waterproofingAll surfaces extensively cleanedA thick, two coat bitumen is laid with a fibreglass mesh between the two coatsThe whole deck surface is covered with laps up the walls and down past the edge to ensure continuityRoof lights have to be included in the bitumen applicationSecond coat of bitumen being laidEvery joint in construction materials is coated to ensure no leaks can occurBitmen is then covered with a slip coat and protective drainage membraneProtective drainage membrane the allows patio finishes to be installed without piercing the bitumen below

Waterproofing Method

The drainage for this property consists of both natural falls on concrete floors, along with perimeter drainage, both internally and externally, all linked to 3 pumping stations containing 2 pumps and an internet-based monitoring system supplied by Hades Sump Monitor.

The external deck was waterproofed using a external barrier system (Type A as per BS 8102). The deck was laid to fall with concrete including integral waterproofing additives, and then layered with a homogeneous bitumen coat with fibreglass reinforcement, covered with drainage layers and slip coats to prevent tears. The deck finishing layers where then applied on top.

For more examples of deck waterproofing projects by Beautiful Basements click here & here

All waterproofing materials supplied by Triton Systems Ltd & Koster Aquatecnic

Categories:
Client: Cotswold Oak
Location: Hertfordshire
Surface Area: 100 square metres
Completed: 2018
Architect: Swimming Pool Design and Management Ltd.
Link: Visit project