Research

Our windows perform extremely well against weather and intruders and insulate against cold and noise, and they last a very long time.

The reasons for this is that we are motivated as a company to provide products that meet this criteria and invest considerable money and energy into doing so. We have got to our current position by looking at:

Timber

We have to use timber that is naturally durable, will allow the coatings to perform well and come from sustainable sources. We have researched windows that have lasted well. Almost all of them have durable hardwood cills with redwood heartwood for everything else. More information.

 

 

Preservation

The only preservative applied to windows in the past was lead based paint. This proved very successful but is unacceptable now. We are making our windows to last well in excess of 50 years and as organic based preservatives are unlikely to remain stable for that period we have researched the use of boron based preservative and the results show that it is the best material currently available and as it is a natural material, less likely to cause environmental damage. See Borax for more information. We are also involved with a joint European project that is looking at high temperature treatment with modified linseed oil. This may result in exciting new methods.

Joint Design

Window joints were traditionally mortice and tenoned. Prior to assembly the end grains and the mortice holes were soaked in lead based primer, assembled and wedged. This method was replaced with glued comb joints which has been a major cause of failure. In 1989 Barnsdale won a substantial DTI Smart Award to look into joint design. We are still researching new methods but have concluded that if a liberal coating of resorcinol formaldehyde is applied to the end grains and the joint long term performance is extremely good.

Glazing

Failure of double glazed units, glazing beads and joints have been a major problem. Our research has centred on reducing the exposed timber beads and reducing the exposure of the units sealant to moisture. Our internally beaded drained and ventilated system has proved to be very satisfactory.

Coatings

If the coating of a window remains intact a well made timber window will last indefinitely. We have carried out extensive work on the overall design of the window to allow the coating to perform well and on the coatings themselves. As a result of this we saturate the assemblies in primer, apply a mid coat and then a top coat of a different colour. As the coating erodes it will finally expose the mid coat which will indicate recoating is required.

Partners in Research

A J Charlton & Sons Ltd

Foreco Dalfsen BV Dalfsen, Holland

SHR Timber Research, Holland

BRE (British Research Establishment) Garston and E ast Kilbride

British Woodworking Federation, London