L-Shaped Dormer: Designing L Shaped Dormer Loft Conversion the Right Way

Adding an L shaped dormer loft conversion is one of the best ways to increasing the space and value of your property, whether you wish to extend the house for your growing family or to create some extra income.

L-Shaped loft conversions are a sensible and often inexpensive way to add that extra space along with value to your property. With successful layout arrangement and beautiful design, your loft could be transformed into a comfortable living space to capture space and light!

Depending on the size of your house, dormer loft conversions can usually increase your existing home by 20-50m2. Every bit of space under that pitched roof has the potential to be utilised.

This article takes you step-by-step through the process of designing and building your L-Shaped Loft Conversion that will add space, comfort and value to your house. 

You’ll view examples of great loft conversion projects designed by Urbanist Architecture and an explanation of why they work so well. You’ll learn essential loft interior design tips and tricks. You’ll also learn how to hire an architect, secure planning permission and stay in control of your dormer loft conversion project.

Let’s jump right in…

Why design and build an L Shaped Loft Conversion?

Often, whether you get a loft conversion or not was a simple decision about giving you more space at home. It may be that your family had grown in size, you needed more space to work from home or that you wanted to add value to your property to make it more attractive to a greater number of potential buyers. Sometimes moving to a bigger property just isn’t an option and this is where a good quality loft conversion really comes into its own.

Let’s face it: moving house is an expensive exercise and one of the most stressful experiences you can go through. It can be a serious hit to your bank balance and not just in terms of the cost of the property itself; fees and supplements, removals and stamp duty, not to mention the cost of refurbishment can mean that costs quickly spiral far beyond what you would like. Throw in the rising cost of house buying and the need for substantial deposits and that loft conversion is looking like an even better option!

An architect designed loft conversion can add a terrific amount of value to your property as well as maximising space in your home. If you do it right, with care and thought, your loft conversion can be a superb investment as well as a project to remember for you and for your family.

News flash: A quality loft conversion can add four time the value of a brand new kitchen, bedroom or even bathroom to your property. If you ask the experts, they will tell you that a well designed loft conversion is often top of their buyers’ wish lists and something that they look for in saleable properties.

Whilst there is some initial outlay to get the project off the ground and completed to a high standard; the long term investment and value added will far outweigh this initial expense and that’s not to mention the extra space that the whole family will benefit from. And when you are ready to up sticks and move on, you’re virtually guaranteed to sell at a higher price than you paid and bank yourself some tidy profit.

What is L Shaped Dormer Loft Conversion?

Simply put, an L-shaped dormer conversion is where two dormer builds are constructed in a way that they join together. Usually one dormer will be built on the rear roof and the other on the main roof which gives it the unmistakable, instantly recognisable L-shape. 

The shape itself means that L-shaped dormers are only suitable for certain types of property, mainly either Edwardian or Victorian properties where there has been an addition to the original house at the rear, known as two storey outrigger. This type of build is a great way to get some more space out of a property like this especially if you own a mid-terrace property.

How to design a Loft that’s bright, airy and welcoming?

Here’s the most important part: Loft conversions have to be treated as more than just a box on a roof. They are to be the successful addition to your property that you want them to be. They have to be light an airy and the good news is that this is easily achieved as you have so much roof space to deal with and therefore the potential for masses of natural light.

You can channel so much light without the need for wide out skylight space; a small aperture on the roof can give you the same quality and depth of light as a far larger opening (like a window) on the side of a property. In terms of natural light, the world is your oyster when it comes to loft conversions as they can be absolutely flooded with light.

With so much natural light at your disposal, your loft space with L shaped dormer loft conversion will appear so much bigger and more spacious than it actually is.

How much does a Loft Conversion cost?

Unsurprisingly the cost varies depending on the scale and complexity of the work.

A basic room in the loft: This is the cheapest type of conversion and will typically be somewhere in the region of £20,000. With this type of renovation you can expect the floor to be reinforced, two skylights, a staircase for access, full electrics, fire safety measures and insulation.

Insertion of Dormer Windows:  You get all of the above with something like this plus the addition of dormer windows. These increase floor space, add height and give you more natural light. They help with staircase access too. You won’t get anything cheaper than £25,000 and if it’s a dormer conversion with a double bedroom and en suite you’ll be looking at anywhere from £30,000 to £35,000.

L-Shaped Dormer Loft Extension: This is the most expensive type of loft conversion as it requires the most technical structural work; the roof needs to be removed and then rebuilt. You will need an architect and you may need planning permission depending on the limitations of permitted development rights, so factor in these costs and time constraints. The best L shaped dormer loft conversion price you’ll get for a job like this is £40,000 but realistically you will be looking at nearer £50,000.

Do I need Planning Permission for L Shaped Dormer Loft Conversion?

You may probably already know that recent changes have been made within planning which allows most single dwelling house owners to convert their loft into habitable rooms without planning permission. You only need to make a Certificate of Lawfulness application for which your architect will need to prepare your loft planning drawings and your application form.

What is Permitted Development Rights?

Permitted development rights basically gives you permission to make certain changes to a building without the requirement for planning consent. It is approved by the Parliament itself rather than the Local Planning Authority (usually your Council).

But first a warning: This is generally applicable for the building projects located outside of conservation areas and only which intend to propose minor changes. However, in some circumstances local planning authorities can suspend permitted development rights in their boroughs by issuing Article 4 Directions and this is happening more and more. Make no mistake about it…

The simple truth is Article 4 Directions do not stop development. Rather, under these directions, you must pursue Planning Permission for adding a loft extension. 

What changes are permitted?

Your loft extension is subject to certain limits such as an additional 40 cubic metres for terraced houses and semi detached house, and 50 cubic metres for detached houses. Keeping to a conservative and modest design is compulsory, as altering the characteristic of the original roof will not be classified as permitted development. An example will be adding a balcony with a balustrade, projecting from the building, or using contrasting colours to the original house.

Alterations to the roof space with additional room falls under Class B of Permitted Development Rights. The drawings your architect will be submitting for your Certificate of Lawfulness application should indicate that the design of your loft conversion meets the limits and conditions of permitted development rights. Failure to do so means that your application will not be accepted.

Your loft conversion is permitted by Class B subject to the following conditions:

• the materials used in any exterior work must be of a similar appearance to those used in the construction of the exterior of the existing dwellinghouse;
• the enlargement must be constructed so that other than in the case of a hip-to-gable enlargement or an enlargement which joins the original roof to the roof of a rear or side extension the eaves of the original roof are maintained or reinstated; and the edge of the enlargement closest to the eaves of the original roof is, so far as practicable, not less than 0.2 metres from the eaves, measured along the roof slope from the outside edge of the eaves; and other than in the case of an enlargement which joins the original roof to the roof of a rear or side extension, no part of the enlargement extends beyond the outside face of any external wall of the original dwellinghouse;
• any window inserted on a wall or roof slope forming a side elevation of the dwellinghouse must be obscure-glazed, and non-opening unless the parts of the window which can be opened are more than 1.7 metres above the floor of the room in which the window is installed.

You will require Planning Permission if:

• any part of the dwellinghouse would, as a result of the works, exceed the height of the highest part of the existing roof;
• any part of the dwellinghouse would, as a result of the works, extend beyond the plane of any existing roof slope which forms the principal elevation of the dwellinghouse and fronts a highway;
• the cubic content of the resulting roof space would exceed the cubic content of the original roof space by more than 40 cubic metres in the case of a terrace house or 50 cubic metres in any other case;
• it would consist of or include the construction or provision of a verandah, balcony or raised platform, or the installation, alteration or replacement of a chimney, flue or soil and vent pipe.

What is Certificate of Lawfulness?

A certificate of lawfulness is a legal document rather than a planning permission. Many homeowners in London and in the UK took the advantage of permitted development rights through making Certificate of Lawfulness application. They have converted their lofts into bedrooms and you can join them too!

So who will help me complete the Legal Requirements?

Here’s all you have to do: Seek for professional help from an architect who has proven track record in securing consents for loft conversions. Any contravention of the limitations on or conditions belonging to permitted development rights constitutes a breach of planning control against which planning enforcement action may be taken.

And remember: Your council may issue you an enforcement notice which can lead to prosecution with a maximum fine of £20,000. And if your council achieves a successful conviction for failure to comply with an enforcement notice, they can apply for a Confiscation Order to recover the financial benefit obtained through unauthorised development.

Do I need Building Regulations approval for L Shaped Dormer Loft Conversion?

You will also require Building Regulations approval to convert a loft or attic into a habitable space so make sure your architect and structural engineer prepare the necessary building regulations plans, and structural specifications and structural calculations.

Let’s not forget… Doing it on your own or skipping this step and heading straight to construction is certainly not advised as this could mean pocket-burning fines!

How to choose an architect for Designing and Building my L-Shaped Loft Conversion?

So what’s the secret of hiring the best architecture firm?

As with any job, the first thing you need to look for is a track record in delivering similar projects; you want to choose an architect that has experience and knows what they doing. Ask to see portfolios of previous work and quiz them on what they feel the challenges might be on your project.

You aren’t going to be best friends, but you do need to get on with your architect, so chemistry and sharing the same vision is crucially important too.

Good quality communication is also vital. Understand from the outset how your architect will communicate with you to keep you up to date on progress and enable you to make the right decisions. You need to get an idea of whether your architect is a good listener.

How do I pursue L-shaped dormer extension without the hassle?

In order to avoid any loss of cash, hassle and headaches, contact an architect who specialises in loft conversion projects to achieve the most out of your property. Your architect and structural engineer will not only prepare drawings, design your loft conversion and obtain the necessary approvals for you but also will assist you find a competent builder and then manage the project for you.

I’m sure designing and building your loft extension is a top priority for you so if you have any questions or would like to have a more in-depth conversation, just let me know by sending me an e-mail now.

Let’s start a new project together

We have helped more than 700 satisfied clients to achieve remarkably successful projects through creative design and planning strategies. We look forward to doing the same for you.