Building Regulations For Double Glazed Windows

This article explains the current building regulations for the new installation of upvc, windows and doors in your property.

Building regulations are in place to control the standards for the design, construction, and alterations of buildings within the UK. Building regulations set an appropriate standard for properties that have to be complied to when homes are developed and constructed.

The association is developed by the government in the UK to ensure every building meets strict criteria and a proper standard of building so they are constructed with safety and security in mind.

The installation of replacement glazing has been part of building regulations since 2002, meaning every installer of double glazing and single glazing has to work to specific standards of quality and thermal regulation.

No matter how you have your windows and doors replaced, you should get a certificate to prove the installer who completes the work complied with the current regulations.

You can apply to the council directly who will send out an inspector to assess the work, or you can hire a qualified glazing installer that has been registered with a certified Competent person scheme like FENSA and other glazing industry accreditations.



FENSA is the government authorised scheme that approves competent installers for replacement doors and windows in England and Wales. They check that an installation has been completed to the proper building regulation standards.

This scheme ensures FENSA registered installers work to the relevant building regulations. FENSA-approved installers have their ability to install replacement doors and windows routinely assessed to ensure they can still work to the right standards.

Using FENSA-approved installers gets rid of the stress and hassle of having new glazing installed. FENSA provides their vetted firms and individuals the ability to self-certify their work meets the  building regulations.

You won’t need to contact the local council or worry about receiving permission as the installer is able to provide you with a compliance certificate once the installation is completed.

This is much easier and cheaper as you don’t need to worry about inspections from the local authority, fees, and waiting times.


What are the Building Regulations for Double Glazing?

Building regulations ensure windows comply with strict levels of safety and thermal performance standards. A range of factors relating to the types of double glazing and their installation are assessed to ensure:

  • Fire Safety

There has to be some way to escape in the event of a fire, so the opening must be sized appropriately to provide a means of escape. The height and width of the opening has to be more than 450mm.

Regulations state that the when the means of escape exist in a habitable room on the first floor, or on an inner room of the ground floor, they have to be properly maintained.

If there is no means of escape currently in the property then, while it isn’t a legal requirement to create one, we recommend having one installed in every habitable room upstairs or in inner rooms downstairs.

  • Minimum Thermal Heat Loss

Glazing has to be classed as energy efficient and it must offer protection against thermal heat loss. The minimum energy rating for a newly installed window in the UK is a C grade, and we only use A-rated glazing that comes recommended by the Energy Savings Trust.

Windows must also have a required U-value and installers have to be able to provide calculations to show how they obtained the proper U-value.

  • Safety Double Glazing

This type of glazing is added to glass that has been deemed to be installed in a crucial area. Glazed areas within windows that’s 0.8m below the floor level have to have safety glazing installed.

Glazed areas within windows that are 0.3m or below from the closest door then 1.5m from floor level also require safety glazing. Safety glazing is also required for glazed doors or glazed side panels that are between floor level and 1500mm above.

Windows that are located within 800mm measured from the bottom of the shower or bath is also classed as being in a critical location, meaning they also require safety glazing.

  • Ventilation

There are building regulations in place to determine how much ventilation each window and door is required to offer. If ventilation is necessary to meet building regulations then the window has to provide that and therefore it needs an opening.

Typically, how much of an opening it needs depends on the size and use of the room they are getting installed in. Regulations ensure that, unless it is a historical building, brand new glazing has to be double glazed at a minimum. The windows and glazing industry has had to do a great deal of adapting since 1965 when double glazing started.

This means that single glazed windows no longer meet regulations. Low emissivity glass has to be used on the inner pane and the air gap between panes of glass have to be at least 16mm.


Do you Need Planning Permission to Install New Doors and Windows?

There are some circumstances wherein planning restrictions must be taken into consideration before beginning a major improvement project.

Typically, you shouldn’t have to apply for planning permission when installing new windows and doors, as long as they are similar to the size and appearance of the original ones used when the property was constructed. how you might need planning permission for a conservatory.

If you are residing in a listed property, then you will have to gain listed building consent for major work performed on the property, whether internal or external.

You might also have to get permission if you are living in a conservation area or flat. If you are going to drastically alter the appearance of a property, such as installing a large bay window that requires extra building work installed, then you might have to obtain building control permission before beginning work.

Our surveyor will discuss any potential planning regulations with you, but we generally find that it’s rare to need permission from the authorities to install and/or replace doors and windows.

As FENSA approved installers we offer the highest quality installations that are compliant to all building regulations. Speak to one of our representatives who will be there to discuss any requirements with you and find the ideal windows for your house.


Complete Glazing Birmingham
Unit 130, 180 Sherlock Street
Birmingham, B5 7EH
0121 405 1058
Mon to Fri 8:00am - 6:00pm
Weekends 8:00am - 4:00pm



About Us

Complete Glazing Birmingham is a sister company of Mainstream Windows a local double glazing, orangery and conservatory installation company based in Birmingham servicing Solihull, Knowle, Sutton Coldfield, Bromsgrove, Leamington Spa, Warwick and Evesham.



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