Our client asked us to supply and install a waterproofing barrier system and provide a third party warranty for the lower ground floor of their new build property.
The waterproofing solution determined is defined in BS 8102: 2022 “Protection of Structures against Water from the Ground” as a “Grade 3” environment where no dampness is permitted and where the internal environment needs to be managed using appropriate environmental controls.
A combined waterproofing system has been proposed by Damptec Systems Ltd:
- Type C: Drained Protection – internal waterproofing
- Type B: Structurally Integral – designed and installed by third party using waterproofed concrete
Type B waterproofing specification will be provided by a third party. This will require use of water bars and waterproofed concrete via use of additives.
When designing a structural waterproofing system for a new build basement it is essential to install a least two forms of waterproofing as combined protection. This is because no single waterproofing system can be considered defect-free and this principle needs to be considered in the design. See excerpt from BS 8102: 2022 below, which upholds this principle.
Damptec Systems Ltd Installation:
Waterproofing Specification:
WATERPROOFING TYPE C:
Internal: Type C (Drained) Protection
Wall Cavity Drain Membranes
Walls: 8mm cavity drain membrane mechanically fixed to all walls (floor to ceiling) in accordance with the manufacturer’s application guidelines
Condensation Strip
Installation of condensation strip to collect any condensation that may arise on the face of the waterproofing membrane.
Drainage
Newton Basedrain laid level and connected to the sump chamber.
Access/Flushing points:
These will be needed at key periodic locations around the perimeter channel system to enable the system to be maintainable in accordance with requirements stipulated in BS 8102 2022 Protection of Structures Against Water From the Ground.
Sump pump station and battery back up
Installation of a Newton Titan-Pro pumping station designed to collect ground water. The pump station has been specifically designed for below ground applications. The chamber is manufactured from HDPE and when installed correctly it is able to withstand hydrostatic forces encountered with high water tables.
Waterproofing the New Concrete Slab
Floor Preparation:
Application of lime inhibitor prior to the installation of the closed cell insulation and 8mm floor membrane. We always treat new concrete. This method will decrease the danger of the new development of salt efflorescence and free lime egress, and raises the resistance of mineral substrates to freezing and thawing.
Closed Cell insulation board:
Installation of Newton Fibran XPS 500-C, a 50mm deep, closed-cell thermal insulation board made from rigid extruded polystyrene foam (XPS).
Floor membrane.
Installation of 8mm eco floor membrane.
All joints where flanged sections are located will be sealed with waterseal tape. Where studded sections meet, waterseal rope will be used.
Where services (pipework etc.) protrude through the system at the time of installation a seal will be created using either waterseal rope or mastic.
