The design and specification of the conversion was undertaken by basement specialists, Biocraft, who were contracted by Blenheim Estates Contractors Ltd to carry out the conversion as well as timber treatment works throughout the property.
The basement extends over two levels. The lower, smaller area has a vaulted stone ceiling. The larger room has become a modern kitchen/dining room with a stunning view over the Blenheim Estate.
To provide more height in the new kitchen, the Biocraft team first excavated the floor in the larger room and lowered the floor slab. Two new light wells were then created and the new retaining walls clad with stone. A new window was installed to the back of the property and new oak lintels fitted to the existing windows at the front.
To control any future ingress of water Biocraft installed Isola Platon’s BBA approved ‘sealed system’. This involved fitting Platon Multi cavity drain membrane to all basement walls and the vaulted ceiling, whilst Platon P20 membrane, with its deeper stud profile and higher drainage capacity, was laid to the floors. Although there was no evidence of previous water ingress to the basement, to conform to BS8102, a Triton Sump and Aqua Pump was installed in the lower basement to pump water to a drainage point outside if required. Cavity drain membranes work by allowing water to continue to permeate the structure but control it in the created cavity and divert it to a suitable drainage point.
Following installation of the Platon membranes, the Biocraft team screeded the floors, and dry lined and insulated the walls. A flexible 6mm plasterboard was used to line and maintain the profile of the vaulted ceiling. Triton’s epoxy based Trimol 40 was applied as a waterproof barrier on the exposed original stonework in the kitchen.
Biocraft’s Managing Director, Martin Fosbrook said, “We could have used a cementitious tanking system at Bladon Lodge but I believe membranes are more reliable and less prone to defects in installation. I also think they are always a better option for historical or listed buildings as the system is reversible and you can always strip the system out if you need to revert to the original. Membranes don’t change the hydrodynamics of the basement either and therefore don’t change the stress on the building or have an adverse effect on surrounding basements.”
When the property was stripped out, the Biocraft team sprayed all exposed timbers with Tritec 121 Plus and treated embedded timbers with Tribor 20 and Tribor Gel as the timbers were at an elevated moisture content and active woodworm was observed.
Triton is the UK distributor for Isola Platon membranes and also manufactures a complete range of products for structural waterproofing, timber preservation and damp proofing. For more information please visit www.triton-chemicals.com