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Seal of approval for waterproofing

COMPANY PROFILE – Kryton’s concrete waterproofing products are keeping a Belgravia basement dry

When Abbey Pynford took on the construction of an 8 m-deep basement beneath a six-storey Grade ll-listed building, the firm knew it faced some challenges – not least how best to waterproof the space.

The project was complicated by the restricted site conditions owing to the city centre location; having to build through water-saturated sands and gravels into London Clay; and the fact that many water-resistant measures don’t lend themselves to use in basement construction.

Abbey Pynford opted to use Kryton International’s concrete waterproofing products.

“The flexibility and workability of the Kryton product range enabled a number of construction techniques to be employed which best suited the ground conditions and engineering requirements foreach element of the proiect,” says Abbey Pynford divisional manager Lewis O’C0nn0r.

One of the challenges was building the basement with underpinning retaining walls spanning 7.5 m vertically in permanent condition.

“These were constructed through water-bearing gravel and into London Clay using the PynWall underpinning technique and without any water ingress to the completed structure,” MrO‘Connorsays.

The basement was constructed using Kryton‘s Krystol internal Membrane concrete waterproofing admixture and Krystol Waterstop System, which creates a two—layer joint protection system.

“The Kryton products facilitated a very high degree of construction quality assurance, not possible with other products in the same circumstances,” Mr O’Connor says.

Another consideration for Abbey Pynford was BS8iO2, which calls for designers to consider defects occurring in a system and subsequent repairs. Waterproofing the joints was one such consideration.

The Kryton system creates two layers of protection for the joints, with the second layer constructed from inside the completed
structural shell of the basement. This increases quality management as the environment is controlled to be relatively clean and dry. The joints can be inspected pre- and post-grouting and any defects fixed.

“The combination of these factors permitted the development of the basement design and construction process in line with BS8iO2 that may otherwise not have been possible,” Mr O’Conn0r says.

Source: Construction News