SashPro, Green Issues and Building Regs

About SashPro

Over the 15 years that SashPro has been operational in this specialist field, the rise of concern for practical applications in improving window performance has become regulated under Part L Building Regs. At the same time a keen awareness for preserving historic aesthetics appears equally important. Indeed property is valued higher when original period features are left intact.

Simply having your windows draught proofed can alone achieve great results.  Additionally the use of more traditional methods of insulation such as shutters and secondary glazing can also provide substantial improvements, even to Part L 2010.
We are happy to advise on what may best work for you and your property. Please follow this link to a video produced by English Heritage that uncovers some home truths authoritatively. For although we offer 'high spec' solutions we also adhere to these findings:
http://www.english-heritage.org.uk/your-property/energy-efficiency/sash-windows/

On double glazing your period windows

Many of our customers wish to incorporate slim double glazed units, which have been developed recently into their timber windows. They offer obviously higher levels of thermal performance than single float glass. The main reason for their popularity though is that they fit into the rebate section of an existing traditionally made period window. However the best U value (thermal performance) they can offer is 1.6 at centre of pane. Part L building Regs 2010 requires a 1.6 U value for a given window as a whole, including the sashes and framework. It has been calculated that a double glazed unit therefore would need to provide a 1.1 U value to achieve this which would be at least 15mm in thickness and would require the sash frame to be specially made to encorporate a deeper rebate.

Building Regulations

Within existing housing stock an English Heritage white paper protects existing period sash windows declaring them “historic” and thus exempt from Building Regs but only in cases of refurbishment or part replacement. Renewal windows, even in conservation areas, must comply but can be exempted upon applying to your local building control who might see that continuity of the period look takes precedence over regulations concerning thermal performance. Listed buildings are normally exempt. However English Heritage agree that we should take building regulations in the “spirit in which they were meant”. So making an effort to utilize modern techniques of weather proofing sash windows is encouraged.

Reasonable Solutions

Taking into account the information above the options left open to you are considerable. If you have original sash windows and wish to improve thermal performance you're already half way there. Consider this quote, direct from Building Acts & Regulations Applied: “The frame of the window effects the thermal performance as well as the glazing fitted. The traditional timber frame offers one of the best insulation standards & simple metal frames the worst. The newer PVC-U frames are manufactured to have almost the same thermal resistance of timber.” 
At SashPro we aim to offer you authentic advice and practical solutions to your fenestration needs. Please take a look around our website for service detail we provide. I hope we have clarified matters for you and look forward to hearing from you.

Max St.John-James