Domestic Property Basement Renovation Part 1 – Drybase Tanking System

The basement was in a state of considerable disrepair and was almost entirely unprotected from the effects of moisture.

There were signs of moisture throughout the basement, caused by a combination of groundwater ingress and a lack of heating and ventilation in the space.

The walls and floor slab lacked any sort of damp protection.

The main consideration for this project was to ensure it provided a safe and habitable environment that complied with BS 8102:2022: ‘Protection of below-ground structures against water ingress’ and provided multiple layers of protection to help keep moisture out. Where that was not possible, groundwater needed to be diverted away from the basement to a suitable discharge point.

This was the first part of a two-phase approach. The team used the Drybase Tanking Range to repair and provide ‘primary resistance’ to the structure. The second phase (to be completed at a later date) will involve installing a Safeguard Cavity Drainage Membrane System to direct residual water to a suitable discharge point.

First, the team ensured the surface was sound and even. Where the substrate was in poor condition, Drybase Universal Mortar was used to repair, make good and left to fully cure before the next stage.

The team used Drybase Universal Mortar to lay internal mortar fillets between the walls and slab. Angled fillets strengthen potentially weak spots while enabling a continuous layer of waterproofing to the basement.

Once the mortar fillets were in place and had cured, the team applied Drybase Crystalline Active Slurry to the floor slab of the basement.

After checking that the Drybase Universal Mortar had set, the team got to work mixing 5 parts slurry to 2 parts tap water with a mechanical mixer. They applied Drybase Crystalline Active Slurry to the channel recess and slab surface with a brush for precision application.

The team opted for Drybase Crystalline Active Slurry for its advanced waterproofing capabilities, such as the ability to withstand both positive and negative water pressure.

Owing to the increased risk of groundwater contact with the concrete floor slab, the team opted for an elasticised slurry to take advantage of enhanced crack-bridging properties and workability.

On the second day, the team mixed Drybase Tanking Slurry with Drybase Elasticiser to form Drybase Elasticised Tanking Slurry.

Once the tanking slurry had been trowelled onto the walls, Drybase Construction Joint Tape was applied to the floor-to-wall joints to ensure a tight and waterproof seal across the entire basement. The team bed the tape into a coating of Drybase Elasticised Tanking Slurry, smoothed off and applied a second Slurry coat.