Dwell Well > Improving > Your Loft Conversion Guide

Your Loft Conversion Guide

Loft conversions are a great way to extend and it is worth noting at the outset that loft conversions are not just restricted to houses. If you have a top floor flat with a roof space above it, you may still be able to have a loft conversion.

In order to carry out a loft conversion, you will need to obtain a number of consents and fulfill a number of statutory obligations.  Let’s take a look at what’s involved.

Will you need planning consent from the Local Authority?

The owners of houses, but not flats, will often have what are known as ‘Permitted Development’ rights.  This means that some types of extensions, including loft conversions, can often be built without having to apply for planning consent.  The rules governing permitted development are quite complex and there are a number of areas where there are no permitted development rights.  Typical examples in London would be a Conservation Area where the Local Authority has issued what are known as ‘Article 4 Directions’.  

Some types of extensions, including loft conversions, can often be built without having to apply for planning consent

If there have been no previous extensions to the roof space it will normally be possible to construct some form of loft extension to a house without having to apply for planning consent.  In the case of terraced houses the volume of the roof space can generally be increased by 40m3 and in the case of semi-detached and detached houses, the volume can be increased by up to 50m3.  

For a very useful document go to the Government's planning portal website. There are also a number of other conditions that also need to be fulfilled, for example, you would not be able to put dormer windows on the front elevation of the house or increase the original height of the roof.  In simple terms, this would mean that if you have a terraced house you could only have a dormer window to the rear elevation and the highest part of the new dormer window would have to be below the height of the top of the original roof. This does not necessarily mean that you could not build a loft conversion that doesn’t comply with the above rules, but you would have to apply for planning consent from the Local Authority and we can advise you on whether your scheme is likely to be approved before you incur too much expense. If you live in a Listed Building you will also need to apply for Listed Building Consent .

Building Regulations Approval.  

Having established that the proposal is viable from the planning point of view you will need to apply for Building Regulations. These are regulations to ensure that buildings or extensions are built to acceptable minimum standards in terms of structural stability, resistance to fire, thermal insulation etc.  You will also need a structural engineer to design the supports to the loft conversion and our structural engineers can also help you with this. Get a quote from a Structural Engineer near you

The Party Wall etc Act 1996

Unless you live in a detached house it is almost certain that you will probably either be altering a party wall or at least building support beams into the Party Wall and this means your loft conversion will be covered by The Party Wall etc Act 1996.  Under this Act, you are required to serve notice on an adjoining owner that will be affected by your proposed works.  Generally, if you are carrying out works that affect a party wall you will usually be responsible for paying the adjoining owners’ reasonable fees in connection with any Party Wall Awards.  Even if you live in a top floor flat you may be able to carry out a loft conversion but you will need to check your lease as the loft above your flat may not necessarily be included in your lease.  You will, in any event, need to obtain the consent of the landlord (usually the freeholder) of the building, as the lease will normally say that the landlord must formally consent to any structural alterations to the building.  Again, and this will probably come as no surprise by now, you would be responsible for paying the landlord’s reasonable legal and professional fees for approving the alterations!


Having established that it is feasible to go ahead with a loft conversion good design is essential to make the space work and add value to your home.

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An Architect or Architectural technologist is the best person to advise you as he should be up-to-date on modern design ideas.

Architects can produce the detailed drawings and make submissions for planning and working with Structural Engineers carry out calculations to ensure the design is safe and meets Building Regulations in order to obtain approvals.

The Build

In order to ensure things go smooth, it is essential to have the works specified. Your Architect should provide full details of what standard of works are required and help with a contract to ensure your money is protected and will be your eyes and ears on site and ensure that the contractor is not cutting any corners.  

For further advice Get a quote from a local Architect

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