A Marshalls Civils & Drainage box culvert



Box culverts by Marshalls Civils & Drainage help speed up an attenuation tank build.

Work is drawing to a close on the construction of three industrial units where a partly bespoke attenuation tank was supplied in super-quick time by Marshalls Civils and Drainage.

The units totaling 29,950ft2 are being built by Castlehouse Construction for client Carnworth Estates next to the Pheasant Fields Lane retail park in Skelton-in-Cleveland, Teesside, and will be occupied by tenants MKM Building Supplies, Howdens Joinery and Toolstation.

The £7 million main contract began in February and features the use of Marshalls’ MC2010 STKA culverts – 32 precast concrete box culverts laid in a double run to create the sub-surface attenuation tank for storage and management of rainwater and surface water run-off from the three units.

Located near the development’s main entrance, the underground tank comprises 20 standard culverts which were delivered immediately ex-stock, and 12 bespoke units manufactured to order. Both have a design life of 120 years and give excellent mechanical and hydraulic performance as the smooth finish allows water to flow through.

Marshalls began manufacturing the bespoke units for delivery on a just-in-time basis as Castlehouse dug the excavation and cast the base slab to start installing the standard culverts. The bespoke units included four end-wall culverts with custom-designed access holes and connections as well as another eight units manufactured with special penetrations to connect the two parallel runs and collect water flowing in from gullies.

The scheme has been delivered to a very tight schedule and construction of the attenuation tank was on the critical path. This meant that any delay in its delivery and completion would affect the overall construction programme.

Marshalls was selected to supply the precast units for the attenuation tank on two main criteria – quality and availability, but from receiving the order to delivery of the first units, the manufacturer had a tight lead-in time of less than 10 weeks.

However, Marshalls’ ability to supply standard units from existing stock was a key factor in keeping construction of the attenuation system on schedule.

Marshall’s Business Development Manager (Special Projects) Billy Fairhurst said: “Being able to use a stock product allowed us to speed up the programme.”

Castlehouse Construction Project Manager Dave Crozier praised the quality of the Marshalls product as well as the support provided by the company during the installation phase.

“Marshalls kept us fully up-to-date with the manufacture of the specials and provided helpful advice to make the installation easier for us. It only took seven days to install all the units, backfilling the excavation as we went. It took us only two weeks to finish the entire job,” he said.

The project included the construction of a car park for approximately 70 vehicles, plus soft and hard landscaping.