Loft conversions - Swoon Architecture - UK leading experts

Loft conversions Adding a loft conversion to your home

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What is a loft conversion and why are they so popular?

Loft conversion is the process of transforming unused loft space into a functional room. You could add another bedroom,  a home office or even a gym – the possibilities are endless.

Loft conversions are very popular in England, they are often unconventional spaces and can have different characteristics from the other rooms in your home.  With the addition of windows you can create a gorgeous light and airy space right at the top of your home.

Loft conversions are one of the least disruptive of all the major home improvements. You don’t even  have to move out of the house as the majority of the work can be done from the exterior of the property. 

Types of loft conversion:

There are a few different types of loft conversion. The costs will vary depending on which conversion you choose.


A Light loft or Velux conversion is a design that uses velux windows.  These are installed into the pitch of the roof, thus allowing much needed light into the space.

Light loft conversions are the most simple and the cheapest type of loft conversions. This can be a good option if the roof height in your loft is already sufficient and you don’t need to extend or alter the structure of the existing loft space and shape in any way.

Essentially what you are doing is adding windows and therefore you shouldn’t need to apply for planning permission.


A dormer loft conversion is where extensions are added to the existing roof and project vertically from the roof slope. Internally a dormer conversion has vertical walls and a horizontal ceiling.

Dormer conversions are very popular – mainly because you don’t usually need planning permission.  However dormer conversions do not always utilise all the space very efficiently. There are a few different types of dormer loft conversion:

  • Flat roof dormer
  • Shed dormer
  • Dog-house dormer
  • L-shaped dormer

Usually , this type of conversion falls within your Permitted Development Rights, therefore you probably won’t need Planning Permission.

The most important question of course is: Is your home suitable for dormer loft conversion and will it satisfy all your needs? Once you have discussed your needs with your architect he will be able to advise you further.

Loft conversions


A hip to gable loft conversion is where the side roof is removed off of the side wall.  This maximises the internal head height.

The space you can achieve with a hip to gable type of loft conversions is much bigger than the space you get with a dormer or roof light type of conversion. However,  this is the most expensive of all the loft conversions as it requires a lot of manual labour and materials. Hip to gable is the most common on semi-detached homes. It’s an ideal solution when a roof has three sloped sides and a small internal space.

Planning permission is usually required as you will be making structural changes to the exterior of your home.


A mansard loft conversion, named after the 17th century French Architect Francois Mansard, is situated at the rear of the property.

This type of loft conversion has a flat roof, with the back wall sloping inwards at an angle.  It does create a much more usable space than any other type of loft conversion but is also the most expensive. 

Almost all mansard loft conversions need planning permission.

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Things to take into consideration when you are thinking about loft conversion:


A loft conversion puts more weight on the foundations of your home.  You must always check that your home can take the weight of a loft conversion.  This is one of the things that is required to be checked by your Building Control Officer.

I would not advise checking the foundations yourself…any mistakes made at this early stage could end up costing you a lot more.


You should ask your structural engineer or architect to calculate precisely how much headroom you will have in your loft when it gets converted. Lot of people get pretty surprised with it.


You should ask your structural engineer or architect to calculate precisely how much headroom you will have in your loft when it gets converted.  It is not always as you would expect.


Natural light is one of the most important things in our loft conversions. It has such a positive effect on us, helps us to concentrate more, according to medical studies it can even help to elevate our mood and also enables the body to produce Vitamin D. There really are so many benefits.

So good natural light is very important.  Always talk to your architect as he/she will have lots of experience.  Think about the aspect of your property,  do you need morning sun or evening light? What’s the differences in natural light  between summer and winter?  Take your time – everything needs to be taken into consideration so you get the very best from your new loft space.


When it comes to heating, insulation and ventilation it is very important that you hire an architect with good experience in this area.  You will also need to make sure your current heating system can cope with the extra room and can warm your whole house.  You may need to upgrade your current heating system.  You could always consider installing renewable energy heaters  – this may increase your initial costs but will significantly reduce your costs in future.

Loft conversions must have sufficient insulation, you do not want all the heat from your home to be lost due to lack of insulation.

Ventilation is not always necessary, but it is generally a good idea. Helping prevent condensation and it can be used to circulate heat to other parts of the house.

Costs of moving versus costs of renovation

Should I stay or should I go now?

This is the dilemma for a lot of people. Depending on the area you live, sometimes it is a better choice to move rather than renovate. You need to work out what your house is worth in its current architectural state and whether or not the cost of the loft conversion will increase the value sufficiently as you don’t want to end up losing money when it comes to selling.  Although it’s not always about money and profit!  If you’re creating your dream forever home then go for it!  Our homes are one of the most important places in our lives.  This is where we make a lot of our memories.

Don’t forget that a good loft conversion has the potential to add 20% value to your home – provided, of course,  it is completed professionally and with good taste. Remember, a badly renovated loft could harm the overall value of your home.

With major works on your house, we advise you to be careful and “Measure twice, cut once.”

Do I need planning permission?

Not all loft conversions require planning permission. Some conversions fall within your permitted development rights. However, you’ll still need to satisfy building regulations.

Accordingly, you will need to obtain planning permission if your plans exceed certain limits and conditions such as extending or modifying the roof space. You will also need to follow stringent building regulations, which are put in place to ensure that construction work is safe.

To check if you need planning permission, you will need the help of an architect or builder. Here is a list of limits and conditions that allow you to NOT need planning permission:

  • A volume allowance of 40 cubic meters additional roof space for terraced houses.
  • A volume allowance of 50 cubic meters additional roof space for detached and semi-detached houses.
  • No extension beyond the plane of the existing roof slope of the principal elevation that fronts the highway.
  • Materials must be similar in appearance to the existing house.
  • No extension to be higher than the highest part of the roof.
  • No verandas, balconies or raised platforms.
  • Side-facing windows to be obscure-glazed; any opening to be 1.7m above the floor.
  • Roof extensions not to be permitted development in designated areas (national parks and the Broads, Areas of Outstanding Natural Beauty, conservation areas and World Heritage Sites).
  • Roof extensions, apart from hip to gable ones, to be set back, as far as practicable, at least 20cm from the original eaves.
  • The roof enlargement cannot overhang the outer face of the wall of the original house.

These terms apply to homes, not to flats and maisonettes, converted homes or homes created through permitted development rights to change purpose, other non-dwelling buildings.

Think again about hiring an architect or builder.

Planning permission is just one of the things you need to think about when getting your loft converted. You should think twice about hiring an architect or builder who will confirm that you meet all of these requirements.
As for the duration of the process, your local planning authority is required to make a decision on your planning application as soon as possible. It does not take more than 8 weeks to decide on an immediate planning application, 13 weeks for a particularly large or complex application, and 16 weeks if an environmental impact assessment is required.

Building Regulations Approval

Whether or not you need to seek approval for loft conversion planning, building regulations approval is required to convert a loft into a liveable space. You will still need to follow the relevant building regulations listed on the Government website and seek approval of the building regulations through the planning portal.

Building regulations are extremely important because they ensure safety. They make sure that any loft remodelling is structurally strong and stable, that the stairs are properly positioned and that it is safe to escape during emergencies.

The type of building regulations depends on the type of conversion you are planning. If you want to turn your loft into a storage space, you may need to seek approval for building regulation. However, if you want to convert your loft into a living space then you will certainly need to seek approval for building regulation.

Of course, this isn’t the complete list – there are plenty more things to be taken into consideration when planning your conversion. When it comes to other permissions, you will need Party Wall Agreement. It’s an agreement between you and your neighbour that aims to ensure that work is done fair and won’t endanger your neighbour’s property.

Also, if you think you have special species, bats for example, living in your loft, you’ll need to have a bat survey. Bats are a protected species. If your loft is home to a roost of them, you may need to obtain a mitigation license to carry out the work.

Fire Safety

According to Building Regulations you’ll have to provide a minimum of fire safety.

Escape Routes

You’ll have to provide a safe route from your loft to the outside. Staircase must provide 30 minutes protection so they will need plastering or plaster boarding.

New Doors

Doors in your loft must be fire rated in the escape route. So, all doors in your loft and   escape route must be changed to fire rated doors. Your obligation according to building regulations is to provide a safe escape route from the lost and through to the outside.

Smoke alarms

You must have smoke alarms on every storey of your house. Alarms must be linked, meaning that if one of alarms triggered, all of them sound.

Also, battery backup must be provided for all alarms in the house.


Existing 1st floor ceilings will need to achieve 30 minutes fire resistance.


Many councils will now accept a small sprinkler system as an alternative to the protection requirements.

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Can I convert my loft?

Good question!!  Is my loft convertible?  The crucial measurement you need to take is from the highest point, directly under the roof ridge, vertically down to the top of the joists below. This should be done with a metal tape measure (ensuring the measurement is kept straight) 

For a conversion to be practical you need at least 2.2 metres.

If the height is less than 2.2m you have two solutions, to raise the roof or to lower the ceiling in the room below.  Of course, this will increase the cost of your conversion.

Roof pitch. Measure the angle of the roof, the higher the pitch angle, the higher the central head height is likely to be.

Footprint. Ideally your loft’s internal walls should measure a minimum of 5.5 metres from one side to another – inclusive of the chimney and 7.5 metres from the front to the back.  However do not be disheartened if your loft space doesn’t quite measure up – always discuss with an architect – they will have lots of ideas to help.

We always advise you to contact a good architect or builder before you start with a loft conversion. They will have lots of advice, ideas and even solutions to make your loft space the best it can be.

How much does loft conversion add to your value?

A loft conversion, if done professionally could add up to 20% value to your property.

Who I should hire?

Architectural practices can focus very strongly on their ability to create good designs and on what sets them apart. However, in doing so, they often completely ignore potential structural issues and complications that could arise due to an impractical built form or shape. They completely depend on the structural engineers to figure it out while in reality it can be incredibly challenging to actually build some of those forms. It can either get extremely expensive or sometimes it’s just not possible to make an odd built form that is also structurally stable.

Our team has an architect, structural engineer and designer, communication among them is a key to our success.

Can I do it by myself?

You could do It by yourself if it is a simple loft conversion. However, it’s advisable to hire an architect or structural engineer who will be able to take care of everything. 

Loft Conversion Costs

Why not use our simple and easy to use cost calculator – this will give you an approximate price for your project. 

Of course, every loft conversion is different so bear this is mind when doing your calculations.  Of course, you can have a free consultation with our team who will be happy to explain everything in detail and get your project started.