May 9, 2014
By Stephen Wright, Managing Director of George Barnsdale
This week is the National Custom & Self Build Week (3rd – 11th May), so I thought that I’d put pen to paper to highlight some key considerations which should be explored when specifying timber windows.
You’ve already made the important decision that timber is the material for your home but with so many products available, it can be difficult to choose.
Hopefully, this consideration list will help. It’s by no means an exhaustive list, but hopefully will provide some food for thought…
1.0 Tried & Tested
Many manufacturers claim that their products are of superior quality, but do they have test data to validate their claims? At George Barnsdale we continuously push the boundaries of product quality and performance and we have extensive test data from third party, UKAS approved test houses to validate our claims. To date, our main product testing has been focussed upon:
- Thermal performance – all of our products have relevant U-Values in accordance with BS EN ISO 10077 and BFRC Certification;
- Weather Tightness – we have carried out extensive air and water testing to ensure our products comply with BS 6375 Part 1, Weather tightness of windows and external doors;
- Operating forces – to ensure our products comply with BS 6375 Part 2, Operation and strength of windows, we have carried out a test that looks at the forces required to open a window and also repetitively tests the process of opening the window;
- Acoustic performance – there are a number of acoustic standards and we have a wide range of test data to the following; BS EN ISO 140-3:1995, BS 2750: Part 3 and BS EN ISO 717-1:1997.
If you have planning restrictions placed upon your build and require us to carry out additional testing, we are happy to work in partnership with you to do this
2.0 Complying with Conservation & Heritage
If you are planning a new build in a conservation area, you’ll find that there are specific planning requirements concerning windows and doors. In most cases, it is asked that the windows and doors should seek to be sympathetic in appearance to neighbouring properties so that the visual impact of the build is minimised.
At George Barnsdale we have developed a Historic Range to specifically meet the stringent planning requirements common for conservation areas, without compromising on performance. This range has been developed in close consultation with conservation officers, building control officers and architects.
3.0 Validation of Guarantees
The majority of manufacturers offer guarantees but before you make your purchasing decision, it’s worthwhile to research if there any ‘conditions’ attached to these guarantees.
Incorrect installation is often a factor for invalidity. To avoid incorrect installation on self-build projects, George Barnsdale will supply the project manager with a copy of the installation manual. If the manual is followed there won’t be an issue with incorrect installation.
Paint guarantees can also a contentious issue. On all products, George Barnsdale awards a 10 year paint guarantee which covers the following:
- Embrittlement, flaking or cracking of the coating system;
- Damage resulting from fungal growth within the coating system;
- Significant yellowing of the coating;
- Premature erosion of the coating film leading to exposed undercoat.
4.0 Site Installation
At what stage in the project are you planning to take delivery of the windows and subsequent installation? I know that it may seem obvious but if the windows are delivered too early, have you a secure place to store them away from the elements as the guarantees are only valid at the point of installation. We have had a few instances in the past where the project has fell behind but the delivery date of the windows hasn’t. We are happy to hold the windows in storage at our factory as long as we have advance notice. Once the windows are installed it is crucial that no wet works are carried out around them.
The timber used has been carefully dried to an accurate moisture content. Too wet and the coating will not work properly and the product will shrink, too dry and it will expand. Our factory has full humidity control to ensure the products are delivered exactly as they should be. Poor storage on site or excessive moisture on the inside caused by wet works may reduce long term performance.