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Building Regulations and Double Glazing

UK building regulations are designed to establish standards that ensure the safety and health of residents.  The regulations apply to new construction as well as changes that are being made to existing construction, and they apply to a variety of home improvement projects, including double glazing.

So, it is important to make sure any changes you want to make to your home comply with the appropriate regulations.


UK building regulations that apply to double glazing

Building inspector with plans

A building inspector will ensure your double glazing meets the regulations

With the average home losing 20 percent of its heat through its windows, the building regulations that apply to windows are designed to improve energy efficiency, while ensuring that replacement windows are just as safe and structurally sound as the original windows.

If you are thinking about installing double glazing in your home, it will need to meet the following standards:



Insulation levels are represented by U values with lower U values indicating higher levels of insulation.  Double glazing with a uPVC or wood frame cannot have a U value greater than 2.0, and windows with metal frames cannot have a U value greater than 2.2.



To help prevent injury, safety glass must be used in areas where people are most likely to get hurt.  This means any double glazing installed within one foot of a door or 2 ft. 7 in. of the floor must use safety glass.  Two main types of safety glass are used in homes today—tempered and laminated.  Tempered glass is four to five times stronger than ordinary glass, and when it does break, it crumbles into dull pieces that won’t cause serious harm.  Laminated glass uses two or more sheets of glass with a layer of plastic or resin in between.  When laminated glass breaks, rather than shattering all over the floor leaving a trail of sharp edges behind, the broken pieces are held in place by the layer of plastic or resin.

If a window cill is less than 800 mm above the floor, preventative measures need to be taken to keep someone from falling out of the window.



There must be adequate structural support above the window or doorframe prior to installing.


Escape Route.

If there is a fire in your home, you must be able to escape through windows in rooms that are not on the ground floor.  You must also be able to escape through windows in rooms on the ground floor if the only other way you can get out of the house is through another room.  Furthermore, if you need a key to open the window, it should be kept near the window to allow for a quick escape.



An adequate combustion air supply must be available for appliances that have an open flue.  If you have appliances like this in your home, you must have a qualified professional verify that the air supply is adequate.  In addition, you must maintain appropriate background ventilation in each room.



If a house was designed to be easily accessible under the Disabled Regulations, it must continue to be accessible after the installation of the double glazing.


Ensuring Compliance with Building Regulations

If you are going to do the work yourself instead of hiring a professional, you must arrange for building regulation approval from a building control body.  There are two types of building control bodies you can use—the local building control authority service or an approved inspector.

Regardless of which one you choose, you must be able to show that you have complied with all of the regulations that apply.  You will also be responsible for any cost associated with the inspection.

An easier and cheaper alternative is to have the work performed by a contractor who is a member of the Fenestration Self Assessment Scheme (FENSA).  FENSA was developed by the Glass and Glazing Federation (GGF), the trade association that represents the industry.

The GGF protects consumers by ensuring windows meet industry standards and the installation complies with all building regulations and planning rules.

Building inspector checking double glazing

All doube glazing must comply with building regulations

Contractors must meet a strict set of requirements before they can become a GGF member, and after they do become a member their work is regularly reviewed to make sure it adheres to the strictest quality standards.

Furthermore, member contractors are required to adhere to a code of conduct and follow industry best practices.  When you choose a contractor who is a member of the GGF, you can be sure that the job will be done right.

Another advantage of using a FENSA contractor to install your double glazing is that they have the authority to self-certify that their work meets all regulations associated with double glazing.

This means the work they do does not have to be inspected by the local authority or an approved inspector.  Since the FENSA contractor is completing the work, they are responsible for reporting it to the local authority within 30 days of completion.

Random inspections of the work performed by FENSA contractors are conducted on a regular basis to ensure compliance with building regulations.  In addition, double glazing installed by a FENSA contractor carries a 5-10 year guarantee on the installation.

FENSA can only be used to certify work on existing residential properties.  If the work you are doing is for new construction or a commercial property, you must contact your local authority to obtain building regulation approval.

Regardless of whether you do the work yourself or hire an approved FENSA contractor, be sure you get a Building Regulation certificate to certify the work is compliant.

If you do the work yourself, the certificate will be issued by the Local Authority Building Control or the approved inspector. If you hire a FENSA contractor, they will issue the certificate.

It is important that you keep a copy of this certificate as you may be asked to provide it to prospective buyers in the event you want to sell your home, to show that your replacement windows meet building regulations.

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