LISTED BUILDINGS CASE STUDIES

Property A

A Grade II Listed property in South Wales within a small village on the flood plain of the main river which has suffered from river flooding up to 600mm deep internally on several occasions over last ten years.

Due to the topography the property is protected by the railway line but this is surpassed higher upstream.

• The property was converted into a top-class restaurant and the owners cannot afford to loose the business due to regular flooding.
• Prior to conversion the Property flooded through the doors and up though the drains when the river banks are overtopped upstream and flows down an old lane to flood the area around the restaurant.
• Generally the walls are 600mm thick stone but the service block is just rendered blockwork.
• Many existing openings had been blocked up using concrete blocks with a timber cladding and ventilation ducts for the kitchen had been taken through at low level.
• A detailed Survey revealed that there is a clay layer on average some 750mm below GL.
• EA want to maintain the flood plain therefore a bund or wall around the property was not acceptable and would not meet the cost benefit analysis criteria in any case.
• The Owners live on the site and wanted a system which they could easily deploy themselves.
• The property has limited notice of flood warnings about 2 hrs.
• Flodef ‘s system was chosen after a full cost benefit analysis as the most cost effective and practical solution under the WAG grant system.

The Solution required a Flodef system completely isolating the service block with an impervious membrane down to the clay layer.  The blocked up openings were protected with a one layer membrane system and the ventilation ducts altered to exhaust above the anticipated flood levels. The doorways within the stonework were protected with the Flodef system with demountable posts to accommodate the wider openings of this commercial property. Drains were fitted with appropriate non-return vales and a sump with pumps was fitted in the food store room for good measure. Listed Consent was obtained by Flodef Limited. The installation was completed in two weeks despite the loss of three days due to weather and working in with the clients business.

Client: Carmarthenshire CC & Mr. & Mrs. J. French

Property B

A detached Grade II Listed property in a Historic North Norfolk Village , built in 1750’s and flooded in 1953 to approximately 1.4m internally. The whole are is now more vulnerable due to rising sea levels, climate change and the new policy of managed retreat being adopted by the EA whereby sea defences in the area are not being maintained allowing the wetlands to return.

• Flooding from the sea nearly occurred last winter but fortunately did not come over the sea road which is about 1m above the general level of this and many other properties in the village. 
• Due to the substantial flint walls around it and the clay subsoil the property is likely to flood through the doors, airbricks and up through the WC and WHB connections along the road frontage should the sea overtop what defences will eventually remain when the eco-system has stabilised.
• Given the mass of the structure and the relative short duration of a likely ‘flash flood’ as it may sweep down the main road the client chose to protect using the main boundary walls and property frontage.
• This required some strengthening of the walls and re-pointing as necessary, protection of the garden gate, main door and low windows, insertion of ‘Smart Air Bricks’ to replace the existing, non-return valves on the main drain outfalls and revision and protection of the cellar ventilation shaft along the road frontage.
• The property has limited notice of flood warnings and therefore it was important that the system is always available to be deployed at short notice and it could be completed quickly by one person if necessary. Deployment takes 15-20 minutes
• The client was very pleased with the end result and the novel methods used by Flodef to provide an effective and economic solution to the potential problem and ‘peace of mind’ has been restored.
• Flodef was chosen as the most cost effective and practical solution by the client from a number of solutions considered.

Client – Private