Building Regulations for Windows – What Are They and How to Comply

Understanding building regulations is essential to ensure that you are not breaking any rules regarding building and safety regulations. These rules must be adhered to, especially if you are a landlord, live in a rented property or are letting a property.

Window regulations also fall under building regulations and cover everything from thermal efficiency and air supply to safety, escape access and ventilation. As a provider of bespoke sash windows in London, we feel we share equal responsibility in providing customers with information on building regulations for windows.

Below, we have detailed the rules and sections that must be adhered to, in order to ensure the safety of both you and your tenants.

The Window Regulations

Fire Safety

There are two aspects to be considered, escape routes and unprotected areas:

Unprotected areas – in the case of external doors and windows, it’s likely they will have to be fire resistant; what this means is that the doors must swing shut (self-closing) and windows must be fixed to ensure the spread of fire is greatly reduced.

Escape routes – with all building regulations for windows, you must ensure that fire escape windows have an unobstructed opening of at least 0.33m² and with a minimum dimension of 450mm in height or width. If your property features single side opening windows, then they must have a minimum frame width of 610mm. If you have a two-pane side opening window, it must have a minimum width of 595mm.

Safety glazing

If any glass is in a critical area, it should be glazed to ensure the spread of any potential fires are reduced. As mentioned above, an unobstructed openable area (such as a window) should have at least 0.33 square metres and a 450mm high/wide opening.


There are ventilation rules that must be adhered to regarding windows. Depending on the use of the window and where it’s located, ventilation rules will differ. For example, windows featured in kitchens and bathrooms (where the rooms may be steamy) should see greater ventilation systems put in place. This can be done in the form of fans, windows and other openings. Put simply, the more a room encounters steam, the more ventilation it requires.

Protection from Falling, Impact and Collision

As the name suggests, this window regulation takes into account the safety measures in place to prevent falling, impact and collision. With regards to windows, you must ensure that areas fall below 880mm from FFL. What this means is that the windows (that essentially act as a barrier from inside your home to outside your home) are capable of withstanding the forces of impact based on the British Standard BS6180.

Energy Efficiency

If you are considering a door or window replacement, be aware that all replacement windows and doors must now meet the same requirements as new windows and doors. We have detailed what requirements need to be met below:

UPVC Windows – U value = 1.6 W/m2.K and WER Band C
Doors – U value = 1.8 W/m2.K

Note that the U values are calculated for the whole unit (both glazing and frame).

Access to buildings

This regulation is aimed more at doors, but is still an important factor to address. Access to building regulations ensure the property has clear access in and out of the property. Doors must include an opening of at least 775mm and a step of no more than 15mm. It’s important to know the dimensions of your door to ensure that you are compliant to the access regulations. Ultimately, this regulation is to ensure that people who suffer from disabilities have easy and accessible access to the building.


Simply put, this is a slightly newer addition to the list but remains very important. It came into effect on October 1st 2015 and demands properties have a minimum level of security in place. This applies to doors and windows and the regulations state they must be able to withstand physical bombardement from a burglar.

Doors and windows must therefore be installed by professionals and be capable of providing ample security to the property. All doors and windows at Sash Windows London Ltd are built using only the best materials to ensure durability and a fantastic ROI.

For the full breakdown, you can access the Approved Documents section.

Is Your Property Secure?

Our team at Sash Windows London Ltd specialise in the design, creation and installation of long-lasting, durable and aesthetically-stunning doors and windows across London. Whether you are renovating your home and searching for beautiful bi-fold doors or sash windows, or you require new windows and doors due to physical damage or wear and tear, we can help.

Explore our wide range of windows and doors by viewing our product range on our navigation menu. All windows and doors are designed bespoke, so you can rest assured that we have the right windows and doors for your property. After you have purchased your windows or doors, you will be given several guarantees to ensure protection and longevity over your products.

Get in touch with our team today to make your home secure.