Single glazed windows in conversion schemes

So how does that affect our warranty requirements?

Our ‘New Homes’, ‘Social Housing’ and ‘Private Rental Scheme’ policies make reference to the building complying with Building Regulations; therefore we need to ensure that the building is compliant.

Defect Insurance Period: These policies exclude existing elements during the ‘Defect Insurance Period’, so for example; any unaltered window would not be covered. The caveat to this statement is unless ‘major damage’ occurs to an existing element. A typical example of ‘major damage’ would be water ingress through the existing window which would be covered by the policy.

Structural Insurance Period: The building is covered for ‘Major Damage’ which includes cover to the waterproof envelope; therefore it is essential that the fabric can be proven to be waterproof, this would include the windows. This is essentially the main purpose of the ‘Refurbishment Assessment’ by our ‘Refurbishment Surveyor’ to ensure that the existing structure is suitable for warranty.


What information is required?

Existing Windows:

Where existing single glazed windows are retained, the following information will be required in order that our ‘Refurbishment Surveyor’ can consider the single glazed windows as viable for retention:

  • A copy of the Listed Building Consent confirming that the windows cannot be replaced, must be supplied confirming specifically which windows are to be covered by the listing. If the Listed Building Consent is not clear on this matter, written confirmation will be required from the Conservation Officer looking after the scheme.
  • A full condition report confirming that the retained windows are capable of forming a waterproof barrier for a 15 years life expectancy (warranty function requirement). A condition survey should be provided by an independent, competent and appropriately qualified Surveyor or Specialist to confirm a life expectancy of 15 years.
  • In addition to the above, if windows are to be retained and repairs are required, a full repair schedule will be required, for appraisal by the ‘Refurbishment Surveyor’.
  • Ventilation design information relating to the scheme will be required for consideration in order to demonstrate how Part F of the Building Regulations.

Once the above information is received the ‘Refurbishment Surveyor’ will then be in a position to fully consider if the retention of the existing windows will offer ourselves a standard insurance risk.


Other policy requirements

It should be noted that in all our other current warranty policies ie. self-build, completed housing and commercial; these have full exclusions for existing building elements. However, where a particular element is to be upgraded this may mean the existing element would now be in cover where previously it was not.

Risk managing single glazed windows in conversion schemes


This technical update provides guidance on risk managing single glazed windows in conversions schemes.

For a number of years there has been some difficulty in achieving a satisfactory level of performance when dealing with listed buildings or buildings that fall within a conservation area.

Traditionally in such buildings it is the Local Authority Conservation Officer who may have jurisdiction in these buildings and although there are requirements in Building Regulations to upgrade thermal elements, it is accepted that historic buildings and building lying in conservation areas may not need to meet these requirements if the Conservation Officer feels that the upgrading of the building would have a detrimental impact to its historic status.

Download a PDF version of this article

Want to download a version of this article?

Download PDF

Every care was taken to ensure information in this article was correct at the time of writing (November 2020). Guidance provided does not replace the reader’s professional judgement and any construction project should comply with the relevant building regulations or applicable technical standards. For the most up to date LABC Warranty technical guidance please refer to your risk management surveyor and the latest version of the LABC Warranty Technical Manual.

Related Articles

Good practice guide to I-joist installations

Learn about essential good practice for I-joist installations with our comprehensive guide covering a range of installation...
Read More

Roof integrated PV solar panels

Learn about the requirements and considerations for roof integrated PV solar panel systems in this technical update.
Read More

Deflection heads – avoiding accidental loading of non-load bearing internal walls

Learn about preventing accidental loading of non-load bearing internal walls with deflection heads.
Read More