UK Manufacturers of Bespoke Timber Windows and Doors

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

Understanding building regulations is crucial 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 timber windows & doors, at nine zero we feel we share equal responsibility in providing customers with adequate information on building regulations for windows.

Below, we have summarised the rules and sections that must be followed, in order to ensure the safety of all our customers.

The Window Regulations

Fire Safety

Since Grenfell Disaster, fire safety has been brought very much into the limelight with people’s safety at risk due to fires. 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 significantly 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. This is dependant on where the window is located and the use of it. For example, windows featured in kitchens and bathrooms (where the rooms may be steamy) should see more ventilation systems. The more the room encounters steam, the more ventilation it requires, which is why ventilation systems are put in place. This can be done in the form of fans, windows and other openings

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:

Timber 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 a key 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.


Building regulations demand properties to have a minimum level of security in place. This applies to doors and windows and the guidelines state they must be able to withstand physical bombardment from a burglar.


Doors and windows must therefore be sufficiently robust, fitted with appropriate hardware and installed by professionals and be capable of providing ample security to the property. All doors and windows at Nine Zero are built using only the best materials to ensure durability and a fantastic ROI

Is Your Property Secure?

Here at Nine Zero we specialise in the design of long lasting, durable and aesthetically pleasing doors and windows. Whether you are renovating your home or are just in need of 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.