Yes, but you will need to obtain planning permission. Converting a detached garage into a self-contained living space, such as annexe, studio flat, or retail unit, represents a material change of use, particularly if it will function independently from the main house. This is because the garage would no longer be used in connection with the main dwelling and would effectively become a separate residential unit.

To qualify as permitted development some household building work projects – notably extending a house – must not exceed limits to the volume being added.  

In England, the volume allowance mostly applies to loft conversions. You can read more on the Planning Portal. 

Use the volume calculator to find out the volume of several loft conversion and extension types.

If your proposal for planning permission or building regulations approval is solely for extensions or alterations to a disabled person’s house to improve access, safety or comfort then you are exempt from paying a planning or building control fee. Additionally, if you are providing means of access for disabled persons to public buildings you are exempt from any fee.

Note that for building regulations approval, you will only be exempt when applying to a local authority building control body.

Changing a standard garage door to an electric garage door will not normally require planning permission. Instead, they are covered by permitted development rights.

Permission may be required if your property is listed, you live in a conservation area or there will be a visual impact on the appearance of the house as viewed from the street. If you are unsure, it is advised that you contact your local planning authority.

Work to install an electric garage door must comply with Part P of the building regulations. This can be done by using an electrician who is registered with the competent person scheme.

‍Visit the website for registered electrical competent persons.

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Inefficient windows and doors can significantly contribute to heat loss. Replacing single glazed windows by installing double glazing can cut heat loss through windows considerably. Double glazing works by trapping air between two panes of glass creating an insulating barrier that reduces heat loss, noise and condensation.  

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If you can't replace all the windows, why not choose the rooms that cost you the most to heat? Other options to reduce heat loss through windows include sealing gaps or using thermal blinds.

You don’t usually need planning permission for repairs, maintenance and minor improvements or replacing windows and doors that are of a similar appearance.

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Building regulations apply to replacement glazing, in terms of thermal performance, air supply, ventilation, safety and means of escape.

Read about planning and building rules for doors and windows

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