Water tight concrete for commercial building for BBC studios

BBC Studios Cadiff






Location type

BBC Studio


November 2016

The challenge

BBC Cymru Wales has picked Cardiff for its new state-of- the-art headquarters - 150,000ft2 and designed to accommodate 1,200 staff. Having developed another building in an adjacent area in Cardiff Centre, within close vicinity of the River Taff and the high water table, Tarmac were well known to the developers RightAcres. Being aware of the challenge to keep the basement areas and cores dry, they would have to dig sink holes at strategic areas and run pumps 24/7 to extract water until the basement was complete. Keeping the water out to Grade 3 standard BS8102 after they were turned off would be down to construction materials and building expertise. The amount of pile caps provided a challenge on its own due to the complex detailing of membranes – this was converted to TOPPROOF.

Our solution

To create TOPPROOF, Tarmac teamed up with their waterproof partners Sika who have more than 50 years track record of BBA certificate approved waterproof solutions. TOPPROOF waterproof concrete contains two specially formulated admixtures. The first reduces the water/cement ratio, increasing the density of the mix and minimizing the size of the pores. The second fills the remaining pores to ensure a completely watertight finish. This means there is no need for external membranes, reducing cost and labour. Client engagement early on allowed the solution to be specified.

Results and benefits

Over 1,500m3 of TOPPROOF was supplied to the contract and all parties were extremely happy with the results. TOPPROOF is laid in exactly the same way as ordinary concrete so no special skills or equipment are required. However, Tarmac also offered professional, on site support. TOPPROOF is less susceptible to early age and drying shrinkage cracks which are both common problems when external membranes are applied. It is also better for the environment compared to conventional methods of waterproofing.

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Additional info

Complex structures 

TopProof waterproof concrete is available in as a self-compacting concrete to form complex waterproof structures.

Low porosity

TopProof waterproof concrete has a very low porosity for reduced permeability to water and water vapour. 

Time saving

TopProof waterproof concrete can eliminate the need for additional membranes or finishes, simplifying designs, saving time and helping to eliminate site waste.

Water tight concrete for commercial building for BBC studios contact

TOPPROOF case studies