Picote UK Ltd were thrilled to receive the UKSTT Award for Small Renovation on October 1st 2025. The winning project was an interesting one in the South of England, in beautiful Beaulieu. A sensitive location combined with a challenging engineering problem made the success of this project very satisfying!
An urgent pipe repair was needed. Two pipes which run parallel to each other under the Beaulieu River were severely corroded and had tidal ingress issues. The chambers were over 4m in depth on either side of the river with narrow access on the downstream side.
Various methods of repair were considered. All were deemed to be unacceptable due to the risk of contamination to the river and difficulty in drying the pipe out.
Traditional Sliplining requires access pits, large winching or pushing equipment and expensive pipe welding equipment. Picote Solutions UK Ltd have previously carried out Flexi-Sliplining projects, including in tidal situations, so presented this option. After discussing the works with Southern Water and Cappagh Browne Utilities Ltd the consensus was to use the Flexi-Sliplining method. 
The small worksite footprint, low disruption and high quality finish of the final product were important factors.
The works involved installing two full length Flexi-Sliplining pipes into two DN225 cast iron pipes underneath the river. The total length was 160m. The original pipes had multiple infiltration locations, were badly corroded and were in a fragile condition along most of their length.
The Method
The host pipe was inspected and various dollies pulled through to determine the most suitable size of pipe for installation. The largest dolly was DN160. It was determined that the 140 mm (OD) and 123 mm (ID) would be best.
Pipes were supplied in 6 metre lengths and 30 sections were welded on the riverside grass. Both lengths were welded on day one, with each weld taking approximately 10 minutes. In total the welding took around 9 hours, including set up, cutting, cleaning and welding. One key benefit of the system is that pipe can be pulled through a “live” pipe; water can flow through the pipe as it is pulled in, so the tidal nature of the location and the fact that the pipes were suffering from infiltration did not affect the work.
The local donkeys were curious but were not affected. Rollers were placed at various locations to aid the process of pulling the pipe.
The pulling head was secured into the start of the pipe and the winch rope attached. The pipe was guided over the frame and through the pipe guide in the base of the chamber. A small battery-powered capstan winch pulled the pipe into place at a rate of approx. 8m per minute!
Once the front of the pipe reached the downstream chamber, the pipe was allowed to rest for 20 minutes allowing any tension to naturally reduce.
The second downstream section was installed in the same manner as the first with no issues. Both pipes were secured into the existing chambers using a patch liner. The project was completed within 2 days.
The Picote Flexi-Sliplining solution provides a stand-alone pipe SN4 or SN8 – a new pipe for 50 years.
– HPWJ tested to 180 bar by WRc (In accordance with WIS 4-35-01 2008 appendix B)
This particular repair would not have otherwise been possible without very expensive excavations, if at all.
