Even good-quality concrete will allow water to permeate the surface; hence the need for a product such as Sika’s watertight solution which improves concrete’s resistance to infiltration. Capillary pores provide a pathway for water ingress where there is water on one side of the structure and air on the other. The volume of capillary pores in the concrete matrix is proportional to the water/cement ratio. Understanding and controlling water/cement ratio is the basis of concrete technology and, as well as permeability, how it affects the strength and durability of concrete.
Case study – Birch Place retirement village
Sika Watertight Concrete formed part of the waterproof solution to safeguard a basement car park against the twin perils of damp and water ingress.
Birch Place is a ‘retirement village’ based in Duke’s Ride in Crowthorne, Berkshire. Designed “with the over 70s in mind”, as well as containing modern, luxury apartments, the development comprises a residents’ basement car park. Contractor, Biggins and Gallagher, on behalf of The Hackwood Group, was selected to provide a proven waterproof solution to ensure the facility is free from the threat of water ingress and resulting damage.
Waterproofing work on the basement car park began in August 2017. It required the application of concrete supplied by CEMEX – containing Sika Watertight Concrete as an additive – to provide a durable, watertight finish to the car park’s walls and floors. State-of-the-art Sika admixtures are added to the concrete’s designed mix at the batching plant to prevent water ingress and any potential penetration to the structure.
Sika BentoShield MAX LM provided the basement slab’s initial waterproof layer. Comprising a factory pre-hydrated, needle-punched and PE flexible membrane, the fully-bonded, self-healing product is ideal for basements and other below-ground structures exposed to aggressive ground conditions and stress, or spaces requiring a completely dry internal environment.
The sealing technology of Sika BentoShield MAX LM combines the unique swelling performance of sodium bentonite with high-strength polypropylene geotextiles. It forms a high-strength mechanical bond to freshly-poured concrete to fully-eliminate water tracking.
Ged Gallagher, Managing Director at Biggins and Gallagher, said: “The Sika products were easy to use, and with the support of the Sika team, it enabled us to complete the waterproof basement car park ahead of programme.”
As well as being safe and simple to use, Sika Watertight systems carry a 15-year guarantee backed by the company.
The Birch Place car park’s waterproofing aspect was completed in November 2017 – to the client’s full satisfaction. It meant Sika Watertight Concrete played a major part in providing the residents of the retirement village with a car park that has been furnished with exemplary watertight protection to ensure its stability and performance for many years to come.