Listed below are permitted developments, presented in summary form.
This is a brief overview: Please contact us for advice if you are looking for Loft conversions in Wimbledon across London.

Outbuilding Design & Planning


Rear loft extensions are considered permitted development providing they conform to the following:

  • The additional roof volume created should not exceed 40m3 for attached houses and 50m3 for detached & semi-detached houses (the original house).
  • The additional roof construction must NOT exceed the existing height of the roof or the original house.
  • Any window on the side elevation must NOT be opening below 1.7m from the finished floor level and have obscured glazing.
  • The additional roof construction must be set back at least 200mm from the face of the external wall, distance measured along the roof plane.
  • Balconies, Verandas or raised platforms are NOT permitted


Front loft extensions are NOT permitted development.


Side loft extensions are NOT permitted development.


Permitted development rights are NOT available on designated land, such as Conservation Areas, World Heritage Sites, National Parks, Areas of Outstanding Natural Beauty and National Parks
Works on lofts may affect bats, should evidence of bats exist a specialist survey will be required.

Expert Loft Conversions by GBS Architectural London

You may have seen numerous loft conversions in London and wondered whether the property's new build or period could accommodate a loft conversion. When you bought your home, it might have seemed like the perfect size, but life can quickly change with the addition of children, and you may find yourself wondering if adding a room at the top of the house could prevent you from outgrowing your home.

Indeed, there are numerous benefits associated with getting a loft conversion.

  • A loft conversion creates extra space without extending your home's overall footprint.
  • A well-designed loft conversion can add value to your property.
  • A loft conversion is the most cost-effective way of gaining new space than outbuilding conversions or adding a new basement.

Despite the many benefits, there are essential factors to consider before embarking upon a loft conversion project. So, we have put together this helpful guide to answer your key questions.

New Build Loft Conversions

Due to the construction methods used for newly built homes compared to older properties, adding a loft conversion can be more challenging. This is why you want to work with an architectural designer like GBS Architectural to guide you through the process. Steel is likely required to convert your loft to ensure the roof remains adequately supported.

Once you have decided to convert your loft, you want to make the most of the room you create. At GBS Architectural, we ensure that every design avenue is pursued in our role as loft conversion specialists. When you work with us, you can be assured that your design will be anything but dull. We consider your space requirements, taste and the functionality you have been dreaming of.

Functional Design

Whilst many think a loft conversion adds a bedroom, the space you create can be used for whatever you desire. Living rooms, games rooms, libraries and galleries can all be designed in your unused loft, adding another dimension to your home.

We work carefully on every design to ensure a loft extension is visually appealing and functional. Built-in storage, space for an en suite, and adding dormers all ensure you can use the area within your loft to its full potential.


Although you may not be trying to add value to your home, adding room is likely to affect what your house is worth. Our architectural designers can offer advice on how estate agents or prospective buyers might view your plans.


Do you need an architect for a loft conversion?

It's advisable to employ the services of an architect to ensure the success of your loft conversion project.

What is the minimum height for a loft conversion?

You'll need a minimum of 2.2m of usable space for a loft conversion.

Do loft conversions need planning permission?

Loft conversions don't always require planning permission. However, there are specific parameters your design will need to adhere to, which is why a specialist Architectural service is often recommended.

Will the foundations of my property support a loft conversion?

Adding extra weight to your home by converting your loft can put additional stress on the foundations, so it's advisable to get an expert's advice to ensure your property can support a loft conversion before embarking on the project.

How long will it take to convert my loft?

Loft conversions typically take 6 to 10 weeks to complete, depending on the complexity of the design and whether or not structural reinforcements are required.

Don't find your question answered here:

To speak to a member of our loft conversion specialist team, call GBS Architectural today for a no-obligation chat on 020 3384 9464.

This is not an exhaustive list and you should always seek advice before the commencement of any works.