Loft conversion building regulations might seem confusing but these experts break them down

Loft conversions are a hugely popular way to add both space and value to all kinds of properties, offering many benefits over other kinds of extensions. That said, while they often won't require you to get formal planning consent, you will still need to familiarise yourself with loft conversion building regulations if you don't want to run into any issues.

Many homeowners looking into how to plan a loft conversion feel confused by the world of building regulations – and it isn't hard to see why. There is so much terminology to get to grips with and 'Approved Documents' to look into.

Fear not, though, our guide is here to demystify building regulations for loft conversions and ensure that your new addition runs without a hitch from start to finish.

What are the building regulations for a loft conversion?

If you are still a little unsure of what the building regulations are, let us explain. They are basically a set of standards, made up of Approved Documents, each of which relates to a different element of a property, from its structure to how energy efficient it is. They were put in place in order to ensure that homes are both safe to live in as well as comfortable. They are constantly changing and being added to and these days focus very much on energy efficiency. Whether you are building an extension or converting your loft, these regs will apply.

'Anyone contemplating a loft conversion must ensure that they comply with building and planning regulations,' explains MD of Simply Loft Rob Wood. 'Building regulations will cover structural safety, fire safety, insulation and ventilation, and escape routes.'

Rob Wood

Simply Loft are one of London’s leading loft conversion specialists, originally founded by Rob Wood and his wife Helen in 2010, after setting up Simply Extend in 2008.

Which Approved Documents relate to loft conversions?

Although this list isn't exhaustive, in general, the Approved Documents you should familiarise yourself with when developing your loft conversions ideas are:

• Approved Document A: Structural safety
• Approved Document B: Fire safety
• Approved Document L: Energy efficiency
• Approved Document K: Protection from falling
• Approved document P: Electrical safety

Building regs for structural safety

Approved Document A lays out all the standards that must be met in relation to the structural safety of your loft conversion.

When looking at how to create the perfect loft space, it is often discovered that the roof and floor structures need to be modified. In this case, a structural engineer will usually be brought in do do the necessarily calculations to submit to Building Control.

'The drawings and calculations engineers do are submitted to Building Control,' explains architect Graham Ford of Graham Ford Architects. 'Once the design has been approved and correctly installed then Part A of the building regulations can be approved. This sign off is one of the key parts of gaining your completion certificate, along with thermal design, fire design and all other aspects of the building regulations.'

Graham Ford

Graham is the founder of Graham Ford Architects and has over 22 years experience working on residential, academic, sustainable and commercial projects including the London 2012 Olympic Games. He's the author of The Total Environment Masterplan and has lectured at the University of Manchester, Reading and Portsmouth.

How do you satisfy fire safety regulations?

Meeting the fire safety section of the building regulations is hugely important and a large part of this means understanding fire door regulations.

All loft conversions are required to have a protected escape route leading from the loft to the exit on the ground floor. The route should offer protection from fire for at least 30 minutes. Additionally, loft staircases must offer 30 minutes of fire resistance. They will need to be checked to ensure they comply with building regs.

When it comes to the matter of fire doors, most doors used within a loft conversion will need to be fire doors and fire resistant to 20 minutes.

What building regs relate to loft staircases?

Whatever your new staircase ideas leading to your loft conversion look like, they will need to meet the standards set out in Approved Document K.

Stairs should have a minimum headroom of 2m with a pitch no greater than 42°. In addition, they must not be any less than 800mm wide and their handrails should sit 900mm-1000mm above the pitch line.

Finally, the gaps between any spindles in the balustrades must be no larger than 99mm.

Could building regulations mean I can't convert my loft?

One very important section of the building regulations surrounding loft conversions relates to headroom and, in certain cases, where they can't be met, a loft conversion can be very tricky (or expensive).

'There is a minimum requirement of 2.0m at the top stem of the loft stairs (reduced to 1.9m in the centre of the step if it is under a sloping ceiling), and in addition, many homeowners will want to maximise the finished height to give a feeling of spaciousness,' explains Rob Wood.

The good news is that if you don't currently have the headroom in your existing loft space, there are ways of increasing it – although this may push up your loft conversion costs.

'Whatever the reason(s) for increasing the height in the loft, there are potentially two ways that this can be achieved,' picks up Rob Wood. 'In properties that have a very tall ceiling on the level below the loft, it may be possible to lower the ceilings on that level to effectively increase the height in the loft. This can be intrusive on the household and typically means redecorating multiple rooms. It may also mean having to vacate the home for a period during construction.

'A more popular approach is to raise the roof to gain the extra loft height needed,' continues Rob. 'This will almost certainly need planning permission as it usually falls outside of permitted development rights. Detached properties are more likely to be granted consent than semi-detached or terraced properties. If only small increases in height (5-10cm) are needed this can often be achieved with minimal extra work and cost, but if larger gains in height are to be achieved this may require substantial extra works and potentially replacing the whole roof structure.'

How can you ensure your loft conversion meets building regs?

In most cases, homeowners will use either an architect or loft conversion specialist to oversee their project, in which case they should be able to advise on complying with the regs. In many cases, they will also be able to submit your plans to Building Control.

However, if you have decided to project manage your own extension or loft conversion, the job will fall to you. You can either use the local authority building control service or a private registered building control approver.

Inspectors will visit at set stages during the conversion to ensure it complies with the regs before signing it off and issuing a completion certificate.

If your builder is registered with a competent persons scheme, they might be able to self-certify some or all the work.

What kind of application do I need to submit?

There are two ways to approach obtaining building regulations approval: a Building Notice or a Full Plans Application.

A Building Notice is usually sufficient for smaller projects such as a loft conversion or small extension ideas. Either you or your builder will give notice to your local authority building control that you are starting a loft conversion and provide simple details of the work that will be carried out. Once this has been done, you can begin and inspections will be carried out as the project progresses. While this is a simpler and quicker route, it can sometimes mean having to go back and alter certain aspects that the inspector might not be happy with.

A Full Plans Application is best for larger or more complex loft conversions. In this case, full architectural drawings, specifications and other relevant documents will be submitted before any work begins. While more arduous, this approach means everything is pre-approved.

What happens if you don't get building regulations approval?

If you fail to inform Building Control of your plans and plough ahead without, you risk being asked to go back and change work which could be costly and very disruptive. In addition, it could make it almost impossible when it comes to sell your house in the future.

FAQs

What other approvals will be needed to convert a loft?

In addition to building regs approval, there are other approvals that might be required.

Although planning permission for loft conversions is not always needed, don't assume anything. Although in many cases loft conversions fall under Permitted Development, there are cases where it won't apply, such as in Conservation Areas or where you are working on a listed building.

It is also worth noting that some types of loft conversion, such as those which have significantly altered the existing roof construction, will not fall under permitted development. Your architect, builder or loft conversion specialist will be able to advise you here.

If you live in a semi-detached or terraced house and your loft conversion will affect a shared wall you need do comply with the Party Wall Act.

And, finally, if you don't own the freehold of your house, additional permissions will be needed.

Still undecided on the best way to add space to your house? Take a look at our advice on extension vs loft conversion to help you choose.