This project was a large new build waterproof concrete basement with a swimming pool area. The basement with swimming pool had split levels and various linking sections for other areas of the property complex. Beautiful Basements was asked to provide waterproofing design, complete build, and waterproofing installation. The basement contains a swimming pool, gym & library, garage space and several areas for plant & storage.
Stage 1 – Site preparation creating bases and split levels
The site and all the grounds to be stripped and levelled ready for construction. As the first team on site, Beautiful Basements created access, hard standing and levelled the area for the basement.
With the area prepared, the heavy machinery could gain access. The basement excavation took place in three phases. The first was the upper section, the whole footprint was excavated to that level. This first level then had a concrete blinding slab cast on it.
The second phase was to excavate the lower area for the swimming pool to be created. The area within the basement for the swimming pool was then blinded and sides supported to create a safe space for the team to work.
Stage 2 – Constructing the basement
With the excavation complete, the construction of the waterproof concrete basement with swimming pool could begin.
Swimming pool level slab
The swimming pool base slab was set out and shuttered to form the outline. This area will also include plant and storage are for the pool. Within these slabs the steel work for the base was laid down.
To link the lower slab to the walls, starter bars were included. These bars run from the slab, up to where the walls will be cast later. A kicker with an intent for an expanding waterbar was included for the primary waterproofing system. The sumps for the secondary waterproofing system were also installed in the lower level.
Upper level slab
When the lower level slab was cast and all the shuttering stripped off, the upper level started. The lower level slabs had steel starter bars to link the levels. These bars were incorporated into the base steel for the upper levels and the slab shuttered and cast.
Swimming pool level walls
With the lower section bases finished, the walls were shuttered and prepared for steel and concrete. The kicker and all construction joins were treated with a cementitious waterproofing slurry and a expanding waterbar installed. This helps seal the construction joints within the primary waterproofing system. The steel was installed, shutters erected and supported and finally the concrete was poured.
Upper level walls
Finally the upper level walls were constructed. This also included the cementitious waterproofing slurry and expanding waterbar for the waterproofing. The steel was installed, walls shuttered, supported and cast. This created one continuous structural, all linked for strength.
Stage 3 - Waterproofing
The waterproofing regime on this project had to include a dual-protection system to satisfy the requirements of the warranty provider. Beautiful Basements was the designer and installer for both systems.
Type B – Integral protection
All external walls, all concrete slabs (swimming pool and basement floor) were cast with concrete including a waterproof additive. The steel reinforcing within this structure was designed to reduce the cracking to less than 0.3mm, also providing integral protection. All construction and day joints have a crystalising waterproofing slurry and an expanding waterbar applied to them to waterproof natural weak points.
Type C – Drained cavity protection
At the base of all external walls a recessed concrete channel was created within the slab. All walls and the floor were lined with a cavity drainage membrane (CDM). These membranes were linked to sump chambers via the recessed perimeter channels. Within the sump is two pumps and a high-level alarm. This system is designed to catch any water that is not stopped by the primary system and discharge it automatically. Flushing and maintenance points were installed to allow future servicing of the system.
Both waterproofing systems were designed by Structural Surveyors in Structural Waterproofing (CSSW) in accordance with BS8102:2009
All waterproofing materials were supplied by Triton Systems Ltd