Wadhurst Place, East Sussex

Phi Group are very proud to have been contracted by Newcourt Residential to carry out the design, supply and installation of several retaining structures at their incredible development in Wadhurst, East Sussex called Wadhurst Place. An exclusive development of luxury homes on a difficult sloping site, required the leading retaining wall specialist in the UK to assist with various solutions to retaining requirements on site. We have currently constructed five retaining walls on site, with more to come in the next phases. Our colleagues at Keller have also constructed a substantial King Post wall on site, so a great project for us both. 

The first wall constructed was relatively small Permacrib timber crib retaining wall to a car parking area at the top of the site that was 60.0m long with a maximum retained height of 3.0m. Planting bags were installed together with fencing to the top of the Permacrib wall. As a result of developing a good working relationship with Newcourt on this initial contract, we then turned our attention to the rest of the site, where the site topography and challenging soil conditions made things much more interesting!

The second wall constructed was again a Permacrib timber crib retaining wall, that butted into the King Post wall installed by our colleagues from Keller. This Permacrib wall was larger with a length of 75.0m and a maximum retained height of close to 5.0m.

The third and fourth walls constructed are the largest on site so far, and presented quite an engineering challenge for both Phi and Newcourt. The terraced walls support two plots above with a road below. Levels were being raised on site so our first thought was to use our Textomur reinforced soil system, utilising the site won clay material to the rear. However, as the characteristics for this material were not good, lime stabilisation would be required to make it useable. The geogrid reinforcement would also require excavation to take place at the base of the structure. The site conditions largely comprise of poor quality Aluvium overlying the Wadhurst CLAY formation. There was evidence of historic slips, and care had to be taken not to increase the risk of slope failure by further loading the slope with our new retaining structures. Between Phi Group, Newcourt and their geotechnical engineers GCG, a system of counterfort drains were designed and installed to mitigate this risk. Close communication was required as our retaining wall foundations also interacted with these features.

The flexibility of our approach and the range of solutions we can offer, meant that we were looking at the project as a whole and not just trying to make it suit a particular product. We are solutions led, not product led in our approach. Combining this with the fact that we provide the complete design, supply & installation service in house, meant that Newcourt Residential could have confidence that Phi Group had looked at the project with an end goal of providing an engineered, long term, cost effective solution.

The solution we arrived at, from a geotechnical, cost and aesthetic perspective, was our Andacrib concrete crib retaining wall system. We incorporated planting bags within the Andacrib at 2 no. per square metre face area, so vegetation will be able to establish, and in time hide the structure from view. The Andacrib system is a robust solution with 120 year design life, so will provide maintenance free retention for years to come. The two tiered walls retain over 14.0m in height and have a length of over 200.0m. The face area for both walls is close to 1,000 square metres. I am sure you will agree it is an impressive structure.

The fifth wall was a Permacrib timber crib wall 65.0m long and 4.3m maximum retained height. The timber fits in very well with the wooded surroundings at the lower end of the site. With a 60 year design life, it is a BBA certified solution that looks great and is also more importantly cost effective.

We are hopefully working with Newcourt Residential on the coming phases of this fantastic development, and continuing our excellent working relationship. 


Where we've done it

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