Document L & FENSA Requirements

FENSA - Legal requirements
A.M.B. Glass and Malvern Windows are a FENSA registered company No.: 25721. Please be aware of the following:

  • If you have not paid Building Control fees, it is a legal requirement that your installer is a FENSA member. If not you may be committing an offence and the re-sale of your house may be at risk.

For more information please visit the FENSA web site or contact us.

Document L of Building Regulations - effective 1st April 2002
Effective 1st April 2002 - all replacement window installations in England & Wales will be subject to BUILDING REGULATIONS. This new regulation in particular affects the minimum levels of insulation that replacement windows must have when fitted in your home. Levels of insulation are measured as U values. The lower the U value, the better the insulation level. In future what we may have in the past have referred to as "normal" double-glazing - i.e. two pieces of glass separated by a spacer bar is very unlikely to conform to building regulations. To get the required level of insulation it's almost certain some sort of LOW E glass (typically Pilkington K in the UK - although there are other brands) will have to be used. It may also be necessary for the sealed double glazed units to be Gas Filled (probably Argon).

  • PVCu or timber replacement windows should not have a U value higher than 2.0 W/m 2K
  • Metal windows (Aluminium) replacement windows should not have a U value higher than 2.2 W/m 2K

Exceptions to new Doc L
Conservatories will not be included when the standard commences provided they are separated from the rest of the building (for example by doors) or they are unheated. Historic buildings are expected to "achieve the best they can". Also when replacing a broken sealed unit, it can be replaced "like for like". The regulations apply to the entire window replacement.

With so many replacement windows being installed its been agreed that the industry could adopt a "self assessment" method for administering the many thousands of window installations occurring weekly that will now be subject to building regulations. Basically this means that it will not always be necessary for a building control officer to inspect each installation or for companies to make separate Building Regulations applications.

The Self-Assessment Scheme is referred to as F.E.N.S.A. - Fenestration Self Assessment Scheme. If your contractor is registered with the FENSA self-certification scheme, that contractor may certify that the work complies with the relevant regulations and you will not need to notify the council.

If the retailer is not a member of a Self-Assessment Scheme or the householder is carrying out the work (DIY?) then they will be required to pay for the building regulations application - check with your local council for costs. The time taken to obtain approval will depend on the local authority concerned.

Its very important that all householders recognise the importance of conforming with these new regulations - its very likely that on any future sale of your property you will need to provide proof that you conformed with Document L.

Possible Future Performance Standards for Part L: October 2003

The Building (Amendment) Regulations, SI 2001/3335 and the publication of the 2002 editions of Approved Documents L1 and L2 convey major improvements in energy performance standards in the Building Regulations. However, as described in the June 2000 consultation paper, these changes were only the first of four stages of proposed improvements in the requirements and associated approved guidance that were expected to be introduced in the period up to around 2008.

However it now appears that The Office of the Deputy Prime Minister (ODPM) (The Government office responsible for Building Regulations) wishes to "speed up" the process of these proposed improvements and it has produced a 25 page document which appears to indicate that the Government wishes to bring England in line with Scotland at a U value of 1.8 - by 2005.