Owning a listed building entails some special rules that you need to know and follow strictly. Some of these are applied to your windows, as they are also a part of what makes your house significant. Any repair work to be done on your windows may substantially change its heritage, and thus it is advisable to learn some of these regulations on windows, to learn more about how to handle damages and repairs. Here are several rules that are taken from Building Regulations that may apply to your windows.

Repairs to windows

Repairing faulty windows are possible, however, these alterations should first be consulted with a conservation officer or your local planning authority. Repairs are to be done through specific procedures for the different structures of the windows, such as the frame, glass, shutters, and ironmongery. As much as possible, the same materials are used to repair or reinforce these parts. Glass types that are obsolete such as crown glass should be retained as much as possible. These are some of the examples of interventions that can be done when repairing windows.

You might also want to check out: Replacing windows: window replacement steps you may need for your Grade II property

Thermal performance

Windows that are to be renewed, then there are requirements that also need to be met. It should be in compliance with the current U-value, which is the amount of heat that the glass and framework allows to pass. However, some classes of historic buildings may be exempted in making energy efficient windows if it may significantly alter the character and appearance. This is written under Part L of the Building Regulations published by Historic England.

Glazing on windows

Safety glazing on windows may also be in order. Safety glazing is done in order to protect the glass by reducing the risk of it breaking. If the window is placed within a so-called “critical area,” which refers to its proximity to doors and its height above floor level, then safety glazing is necessary. This is written under Part N of the Building Regulations.


The type and extent of ventilation necessary vary according to the use and size of the room. Higher levels of ventilation are needed for rooms like kitchens and bathrooms. However, only trickle ventilation is required by the Building Regulations for a new replacement window if it is also present in the old window to be replaced. This is written under Part F of the Building Regulations.

Fire safety and means of escape

Fire safety regulations are in order especially if they are near other properties and means of escape should be provided as well. Windows between adjacent properties are categorised as an “unprotected area,” depending on the proximity to the boundary of the adjacent building. Openings of windows should have the same potential for escape as the replaced window. However, for traditional windows that have larger openings for escape, if more than necessary, then it could be sized down under certain terms. This is written under Part B of the Building Regulations.

If you are interested in learning more about listed building regulations, you may check out this link. These regulations are in order to ensure that while heritage is preserved, it is up to modern standards in terms of safety and quality. If you would like to own a listed property, these are some of the regulations that you may need to know before signing up!

This article was written on behalf of Boulton & Boyce by Pieter Boyce. Pieter has an intense passion for English Architectural history and has been specialising in the conservation of original wooden windows and doors for decades. His exceptional knowledge of timber windows and doors, both listed or non-listed, is attributed to his hands-on approach to learning all aspects of the complete restoration of original features as well as having personally surveyed thousands of items throughout his long tenure as a head surveyor for one of the largest window and door restoration companies in the UK. He now runs a boutique wooden window and door consultancy and fervently champions the retention of original windows and doors. To learn more of Pieter’s services, visit his website at www.boultonboyce.co.uk.

Book a Call Send an Enquiry Book a Survey