What is a Dormer Loft Conversion and Why Are They So Popular?




exterior shot of dormer loft conversion - why are dormers so popular in UK

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A dormer loft conversion is a box structure which is built onto a pitched roof. This is the most popular option when converting the loft as it increases the headroom and living area of the loft, is suitable for most houses, and is usually straightforward to build.

As far as construction goes a dormer is relatively simple to build and will probably take a competent builder around five to six weeks from start to finish.

The main reason for including a dormer is to easily increase the available headroom when undertaking a loft conversion. If your property has a pitched roof (which must be 99% of houses in the UK) you should be able to build a dormer.

They are ideal for any property where you are looking to expand the living space because of a growing family or if you want to provide an extra room for a multitude of uses such as an extra bedroom, office, activity room for the kids, or maybe even a home cinema.

In this article we’ll look at why dormers are so popular, how to plan your own dormer loft conversion and, if you need convincing, exactly why you should consider this project above any other type of home extension. But let’s start with the basics.

What is a dormer loft conversion?

A dormer is basically a box with a window which is fitted above the existing stairs. This massively increases the headroom in the loft by making use of the space under the slope of the roof. This in turn of course means there is far more room available in the loft which means it can be converted into anything from a bedroom to a new living room.

Of course, adding windows to the front of the dormer will not only give a great view from the new loft room but will also allow in lots of natural light and, importantly, give extra ventilation into the roof.

A full length flat roofed dormer fitted onto the rear facing slope of the roof can massively increase the available room in the roof which is why there are so many of these types of loft conversions dotted around the UK.

But, because of the sheer size that a dormer can be, it is important to think about a structure’s impact on the exterior of the property and not just the benefits it gives to the actual loft conversion itself.

There have been some monstrously bad loft conversions done, mainly in the 1980s, that had overbearing dormers dominating the front of a property with horrible and tacky ‘gladding”.

A change in the permitted development laws now means that when adding a dormer to a property the structure is put on the rear facing slope of the roof.

And, it has to be said, builders can now make the structural look much more visually appealing by judicious use of materials and blending it in with the current look of the property.

When adding a dormer there are many different types to choose from though the flat roofed style tends to be used more often than the traditional looking gabled type dormer – mainly because it gives more roof space more easily. But let’s look at all the different types of structure that you may wish to consider.

Types of dormer loft conversions

Dormers are so popular because they easily add extra headroom to a roof space that is of insufficient height to include a new room and, importantly, the new loft stairs.

With most modern buildings only having a very shallow pitch to their roof, dormers are necessary to ensure adequate headroom whilst at the same time allowing plenty of natural light into the roof space.

Every loft conversion is different of course, but when it comes to dormers there are two very popular options. The full-width and the box dormer. There are also a couple of quirky alternatives which we’ll discuss below. But firstly, let’s start with the most popular options.

Box dormer

When adding a dormer to a home these are by far the most common of the different dormers that can be seen on skylines right across the UK. Both homeowners and builders prefer them because they are very cost-effective and relatively easy to construct.

Walk down any suburban street in the UK, especially in the bigger cities, and you will see plenty of box dormer conversions. They sit perched on the roof and vary in size (width) depending on what the new living space will be used for and. Of course, on budget.

Full-width dormer

This kind of dormer design or construction, as the name suggests, extends right across the full width of the rear side of the roof. They are extremely roomy but can overwhelm the rest of the property. The easiest full width dormers to construct are on terraced houses from party wall to party wall.

The only difference between a box and full-width dormer is the width. They are built in more or less the same way.

If you’re planning on converting your loft you usually won’t need to look at anything other than a box or full-width dormer. But, for the sake of completeness, let’s complete the list of the different types of dormers.

Cottage or chocolate box dormer

The traditional and for many the acceptable face of dormers! They look far nicer than their bigger and uglier box and full width brothers but, unfortunately, they don’t really add much headroom. More aesthetically pleasing than practical in most cases they are best suited to older properties that already have a large roof space.

If you have a charming cottage that you want to extend this could be an option for you but there is a reason why box dormers are the most popular.

Recessed Dormer

Basically, an inside out construction that is rarely encountered as they add nothing in terms of space or headroom. It is hard to think of any reason why anyone would possibly include this type of structure in their planning.

Gabled Dormer

Used in the majority of cottage dormers a gable dormer design is typically small in size. A hipped dormer is similar but of course has a hipped front slope. The traditional and nicer looking way of adding a dormer in days gone by.

Eyebrow Dormer

Strangely eye-shaped, these kinds of dormers were often used in properties with thatched roofs. They can be incorporated in other properties but their curved shape means eyebrow dormers are difficult to design and install.

From all the above options it is fair to say that when adding a dormer, the majority of those suitable for modern properties will be the flat roofed box shapes though others such as the traditional gabled version do have their place.

The benefits of a dormer loft conversion

There are so many great benefits to having a dormer loft conversion. Let’s look at the main ones.

Increased living space

This is pretty obvious really but nonetheless it bears repeating. The loft is a huge but wasted space.

But put a dormer on the side of the roof and suddenly the loft becomes a large, habitable space which you can utilise as a bedroom, living room, home office, or 101 other things.

More natural light

You can convert your loft and install a single roof light or Velux window. However, if you install a dormer, you will have a greater area of window space and as a consequence far more light will funnel into the new loft room.

Increased property value

Adding a dormer automatically means increasing the living space in your home. This is guaranteed to add value to your property. On average a loft conversion will add around 15% to the value of your home which makes a dormer loft conversion an excellent investment.

If you compare house prices in your area with those with an additional bedroom (compare two-bedroom houses to those with three bedrooms) and you’ll see the difference an extra bedroom can make to the value of a property.

Cost-effectiveness vs moving to a larger home

If you have a growing family the obvious thing to do is look for a larger home with more bedrooms. However, a dormer loft conversion offers you another option.

All things being equal it is cheaper to add a dormer then it is to move to a larger home. It’s not only the purchase price of the new home but also the cost of moving not to mention all the upheaval.

One other thing to consider is that if your house is in the perfect location for schools, shops, and work then you will want to stay put. Adding a loft conversion allows you to do that even when your family grows.

Other benefits

Compared to other types of loft conversion a dormer is a quick and comparatively affordable way to add living space to your home.

Depending on the dormer designs they can look very attractive when viewed from outside.

They not only provide extra headroom from within the loft area but also admit extra natural light. Adding a dormer will allow plenty of scope for personal taste, including the type of window frame, style of window and window decoration.

Planning and preparation

As with any major home improvement project you must grapple with red tape and there are regulations you must follow. Planning permission, the building regs, and the Party Wall Act all have to be considered. But don’t worry, it’s not as daunting as it sounds.

Planning Permission

In most cases, the construction of a roof dormer will not require planning permission providing certain requirements are met.

These requirements are that new loft conversions must not exceed 40 cubic metres in terraced houses or 50 cubic metres in semi or detached properties. Nowadays the dormer must not face the street, so it is usual to find them at the rear of properties.

The new structure also must not increase the height of the roof and any materials used in its construction must be similar in appearance to the rest of the property. And where practical the dormer must be set back at least 20 centimetres from the eaves. This is why you see the flat roof of the dormer sitting slightly below the ridgeline of the roof.

Most UK homeowners WILL NOT require planning permission for a dormer loft conversion.

However, if you live in a property which is listed, or which is in a conservation area, you will have to apply for planning permission before sticking a dormer on your roof. All of which is perfectly understandable.

But even then, so long as planning is granted, the roof dormers will add to the enjoyment and value of the property.

The building regulations

Unlike planning permission, EVERY homeowner must comply with the building regulations when they plan to convert their loft. Again, this isn’t too much to worry about as your builder or project manager will be able to steer you through the process.

Basically, you have to apply for building regulations approval from the local council and their building inspectors will ensure your project satisfies all the different criteria that are outlined in the regulations.

We’ve covered the regs extensively in this article; What are the Loft Conversion Building Regulations? So, feel free to hop across there for a more in-depth read.

The things to remember is that you must have building regulations approval for your dormer and there are no shortcuts. Don’t be tempted to try and swerve around the regulations. The consequences could be severe including having to tear the work down and pay a fine not to mention that your insurance and mortgage agreement would be invalid.

The Party Wall Act

If you’re going to be installing new steel beams in the loft which rest on the party wall it’s only fair you tell the neighbours about it. Put yourself in their place. You’re sitting quietly having breakfast and all of a sudden, a gang of builders start smashing away with sledgehammers and you see an RSJ swing by your window. You wouldn’t be impressed.

You need to have a party wall agreement in place before you begin your project. This will protect in case there are any disputes before, during, or after the construction process. You can learn more by reading this article; XXXXXXXXXXXXXX

Tips on finding a reputable builder

All specialist loft conversion companies will be experts in building dormers. If they aren’t you certainly don’t want to be doing business with them.

Finding a builder is always a nightmare. We’ve all seen Cowboy Builders on TV and we tend to think anyone with a hammer who drives a white van can’t be trusted an inch. Thankfully, there are far more reputable builders than there are cowboys. Here’s a few tips on finding the right builder for you.

1 – Always get at least three quotes.
2 – Ask for proof of insurance.
3 – Make sure the builder is a member of a reputable trade association.
4 – Ask for references – this is hugely important. When you get the testimonials visit the householders and make sure they are genuine.
5 – Ask friends, family, and co-workers if they can recommend anyone. Word of mouth is by far the best pointers you can get.

We’ve covered the topic in more depth elsewhere on the site. Read this article for more help; How to Choose the Best Builder for Your Loft Conversion.

Of all the points above though, number 4 is the most powerful. If builders can’t or won’t provide details of work they have previously done, and don’t have customers prepared to endorse them in person, move on.

Let’s recap

A dormer loft conversion is a great way to add extra living space to your home. They build over the existing stairs and greatly increase the head height and living area of the loft. A good builder will take around six weeks to complete the conversion and a dormer is the most practical and affordable way to add a new habitable space to your property.

Typically, your dormer loft conversion will not require planning permission, though you need to apply for building regulations approval and have a party wall agreement with your neighbour – unless you live in a detached property of course.

All specialist loft conversion companies will be familiar with building dormers and in the majority of cases the build is relatively straightforward. Your dormer will be built on the rear facing side of the roof and its height must not exceed the ridgeline.

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