Tuesday 07 November 2017

Casement and Sash Window Replacement: Complying with Building Regulations

When looking to replace your timber windows it is important to check whether the windows will comply with building regulations.

For example, if you are just replacing the moving parts of the window (the sashes), as opposed to the whole window and frame, you won’t need to comply with building regulations. This is due to the work not going back to the brickwork, meaning that it is viewed by government regulations as being repair, rather than replacement work.

If you have replaced the whole sash window or casement window, including the window frame, since the 1st April 2002 you will need to produce a certificate to confirm that the window complies with building regulations when selling the property.

To avoid having to pay for an assessment to be carried out by your local authority on your window, which is not only timely and expensive but also risks the window not meeting regulations, it is important to check whether the company replacing your timber windows is registered with a Competent Persons Scheme (CPS), such as FENSA.


Assuming your property is eligible, once the work has been carried out, and you have made your final payment, you should receive a certificate in the post, confirming that the work complies with building regulations. This certificate will come directly from FENSA, as opposed to the company that carried out the work. However, if you have still not received the certificate after 4 weeks, contact the company that carried out the work and they should be able to help you.

If your building is over 18 metres from the ground, FENSA will not issue a certificate. If you live in a property which is over 18 metres high, you will need to contact your local council to arrange for Local Authority Building Inspectors to certify that the windows or doors comply with building regulations.

If you lose your FENSA certificate, you can request a replacement to be sent to you from FENSA for the cost of £20*. To do this you will need your FENSA certificate ID number, which can be obtained from the company that carried out the work, along with the property’s full address.

Please note that FENSA certificates are not required in listed buildings, as these windows are not required to meet modern regulation standards.

Find out more information on FENSA.

*price correct at the time of writing.

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