JJ Developments Loft Conversion

Loft conversion company London
Mansard and dormer loft conversion London



Loft conversion
specialists London

When you need a loft conversion London has no better company than JJD Loft Conversion London. Our years of industry experience, showcased in our portfolio of projects, includes stunning mansard loft conversion work, loft conversion using VELUX® windows, and a range of hip to gable loft conversion London wide. Our prices, our service, our results, that is what makes us the right choice for your loft conversion project, so contact us today.


Small Conversion London

With space at a premium and the need to add more to your home, an attic conversion London homeowners need is often the answer. From a small loft conversion in your London townhouse to a complicated attic conversion, our loft extensions are designed to maximise unused space and create the room you want, whatever you need it for. Contact us today to start making the most of your space with our loft extensions in London.

bed with pillows in converted bedroom by loft conversion company london

Mansard Loft Conversion London

Types of Mansard Loft Conversion London

When you get a mansard loft conversion in London, it is built to the rear of your house and has a horizontal roof with a steep sloping back wall. This kind of loft conversion creates a lot of space shaped like an upside-down pyramid. Windows in a Mansard conversion are usually housed within a box-shaped dormer which projects slightly.

When they get an L-shaped mansard loft conversion, London homeowners get a type of mansard roof with a triangular section at the top. This kind of loft conversion is designed to create more space than a rear Mansard as it adds further room. A Double-Mansard is a popular loft conversion in London, and involves the construction of a front and rear Mansard, which effectively adds an entire storey to your property.

Dormer Loft Conversion London

Loft conversion specialists london

Getting a dormer loft conversion in London is a popular choice, an excellent solution for terraced or semi-detached homes. A dormer loft conversion extends the roof vertically to create more headroom and floor space. Unlike a loft conversion using VELUX® windows, London homes do not require structural changes to their roof.

With these loft conversions on London properties, the work is carried out using external scaffolding, generally having little impact on the house. Different types of loft conversion include dormer, internal and rooflight. Each type will vary depending on the type of home (terraced, detached or semi-detached) and its current roof size and shape. Lofts are converted into homes for several reasons: Provides additional headspace and floor space, Economical, Cost Effective Permission is not always required

Rooflight Loft Conversion London

Pros of Rooflight Loft Conversion London

With the loft conversion using VELUX® windows, London homeowners get a loft conversion where the existing roof space is converted to living space without extending the roof structure. The only visible and discernible external change is the addition of some new roof windows.

As loft conversion specialists in London, we do a lot of loft conversion using VELUX® windows, which are often the most sympathetic option when it comes to external appearance. However, because there is no dormer, they do not provide as much usable internal space as other loft extensions.

Because of their flexibility, loft conversions on London properties are not suitable for all houses but in those instances where such a conversion is possible it can provide interesting attic-style rooms without alterations to the exterior of the building.

Hip to Gable Loft Conversion London

Types of Hip to Gable Loft Conversion London

A lot of our loft extensions involve doing a hip to gable loft conversion in London. When a pitched roof reduces the usable floor area, a hip-to-gable conversion can be an option to explore. This kind of loft conversion in London ensures that people entering the space don’t hit their heads when walking up or down the stairs. When positioning loft stairs, consider the layout of the floor below. The loft stairs are usually positioned directly above the existing main flight for optimal space creation. The two popular options of hip to gable loft conversion london are:

  • Half-hip roof consists of a new gable wall built up to about two-thirds height with a small triangular roof added on top.
  • Baby Gable end wall is formed where the upper slope of a gable is converted into a small gable wall.

years of experience


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How looks the process of loft conversions London?

Free estimate

At JJD Loft Conversion we offer a free estimate to start your loft conversion London project. We will work closely with customers and our loft conversion specialists will ensure that we finalise what you want before delivering a fair quote. For any follow up questions, you can contact our loft extensions team.

Architects and engineers

As a full service loft conversion company London wide, we have a team of architects and structural engineers who will help you achieve the best possible design for you and your property. We know that design is personal, and our loft conversion specialists will help you get your bespoke design.

Permissions and construction

When all permissions are finalised, whether a mansard loft conversion or a dormer lof conversion, our loft conversion London team will allocate a senior team leader who will be on site every day until the project is complete. Our loft conversions team will keep you informed from start to finish.


When the work is complete, we will give you a snagging list. Our loft conversion specialists and your senior team leader will check everything and our quality control team will ensure nothing has been missed, before your decoration starts and the scaffolding is removed, that’s our guarantee.


What are the construction works one by one?

The first step is to erect the scaffolding where necessary and start the heavy construction works like new floor structure and new walls.

Next, we will handle the utilities. Our electricians and plumbers will check the existing installations and adjust new connecttions to the infrastucture

Once the installations are complete, it’s time for roofing works and plastering to cover and close the dirty works. This is a crucial, visible step!

Fitting the carpentry and flooring, painting and decorating required elements and walls. After that we check the quality and fix any existing inaccuracies.

Cleaning of the entire site, removal of the unwanted furniture and construction elements. Dismantling the scaffolding and putting the space into use and the most important – Your satisfaction check!

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FAQ with JJD Loft Conversion London

Do I need planning permission for a dormer roof?

In most cases, adding a loft to your roof can fall under what is called ‘permitted development’. However, it is best to double-check with your local authority whether it requires planning permission. This applies especially if the size of the dormer exceeds permitted development guidelines.

Do I need to follow building regulations?

Yes, all extensions and conversions need to follow building regulations. Your loft build will be visited by an inspector who will check that you are following the correct health and safety procedures and best practice.

Do you have enough headroom for your loft to be converted?

If you plan on converting your loft, ideally you want a minimum of 2.3 meters (7 feet 6 inches) from the existing ceiling joists to the apex of the room. A new floor (about 200 mm or 8 inches) and ceiling (about 100 mm or 4 inches) are installed after removing the old ceiling, and then you have a room height of about 2 meters (6 feet 6 inches). If the closest door is standard size, it will be just under 2 meters tall. If you can’t achieve at least 2 meters worth of headroom when you convert your loft, it will be less comfortable but we will provide you with a convenient solution and you will be satisfied.

Will I need planning permission for my loft conversion?

Loft conversions are now considered permitted development in England, which means that they do not require planning permission. However, this new regulation is subject to certain limits and conditions. If your property is located in a conservation area, then it might be exempt from permitted development rules. However, if this is the case, we will take care of everything for you.

Where will the new stairs be placed?

We have an architect and a designer, so we will be able to show you a design of what your staircase will look like.

Can loft conversions add value to your property?

Yes. Building a loft conversion can add value to your home. When it comes to the added value created by space, the location doesn’t matter. Value however depends on what you’re creating with your extension. Loft conversions tend to add a whole new room—bedroom, study, en-suite—to your home.

Can I save money on my loft conversion?

When you choose JJD we offer complete loft conversion services – from design to completion. This includes planning, building regulations, structure, stairs, velux widows, dormer windows, insulation, plastering, heating, plumbing, bathroom fitting and electrical work. As you do everything with one company, it is more cost-effective, and you don’t waste time dealing with separate contractors.

How can we ensure that building regulations are achieved?

If you carry out a loft conversion under Building Notice, it is not advisable. As a professional loft conversion company, we don’t like to ‘wing it.’ We submit plans to the Local Authority before work commences so they can pre-agree on the technical specifications of the loft conversion and they carry out site inspections while the work is in progress to ensure every detail meets with Building Regulations.

Why choose a professional loft conversion company?

Loft conversions are challenging projects that require specialized knowledge, tools, and materials. The DIY route can be costly, time-consuming, and potentially unsafe. For example, if you don’t know what you’re doing, a loft conversion could cost you thousands to put right rather than save you pounds. If you are thinking about doing the job yourself, we wish you good luck. We are professionals who often take up to six weeks to complete our conversions because we work all day every day Monday through Friday.

I have a hot water tank in the way – will you be able to work around it?

If you want to keep your water tanks in the eaves of your loft, you can choose to pay a local plumber for 1 day’s labour and materials. Alternatively, if you want to avoid the cost and hassle of installing water tanks in your loft, we can arrange for our Gas Safe engineer to install a pressurised boiler such as a ‘combi’.

How long will it take you to convert my loft?

A conversion of a loft to a bedroom typically takes 4-5 weeks and dormer conversions take 6-8 weeks. We can give you a more accurate estimate once we have completed an initial survey.