Things you need to know about a loft conversion.


Thinking of extending your home’s footprint to create extra space? Then a loft conversion could be the answer.

A conversion can effectively transform an unused part of a property into a functional living space. In this article, we’ve put together a guide to give you all the information you need about loft conversion costs so that when the time comes, you’ll know exactly what to expect and how best to plan for it. 

A guide to a loft conversion

The cost of a loft conversion can sometimes be a mystery, but with the right research and planning, the investment could yield a worthwhile return on your property’s value when extra living space is added. Specific factors such as location, type of extension, design, materials and the reputation of the construction team selected (architect, structural engineer) will influence the budget. 

You must make sure your budget is being spent on the right quality of materials, labour and other things. Make sure all factors have been considered to avoid any troublesome snags further down the line that could dilute the budget and delay the completion date. It’s worthwhile drawing up a contract between you and the contractor before the project commences. It doesn’t need to be written in legal jargon, just specific and clear enough to detail what you will be paying for, i.e., a surveyor, party wall costs, materials, labour, payment stages, scaffolding, Congestion Charge, parking, local planning/building regs dept, skip hire, waste removal, and clearing up the site upon completion..  

Typically, how much can a loft conversion cost?

Well, anywhere between £55,000 to £80,000. Notwithstanding any unique or quirky design features that could increase the cost. The TV programme Grand Designs is an example of how people get enthusiastic about a specific design and drain the budget! Therefore, keep within the budget, be sensible with your design and be prepared for compromise. 

Also, timing is important. When is the best time to start a loft conversion? This a good question, which only long-range weather forecasts can possibly predict. It’s unlikely that a loft conversion will commence during the winter months, but then again, who knows? It depends on the urgency of the project. As you know, bad weather can seriously set back your deadline, so choose your start date wisely.


Factors that can influence cost

The closer you live to central London, the higher the price tag (usually). Contractors based in or near central London are hampered (not totally) when moving in and out of central London due to ULEZ, Congestion Charges, expensive parking and restricted access. It takes careful planning to move materials from the supplier to the site and keep the costs within budget.     

Pricing for a loft conversion can vary dramatically depending on your location. For a London project, you could budget between £60-100k, while well outside the capital, costs tend to range from £50-70k. Below are a few factors that need to be included when calculating the cost.


Some loft styles may not cost the earth. Velux roof windows are an option that could be right for you. A standard loft conversion (no extension) that makes use of once empty space (apart from the cold water storage tank) could be what you require; nothing fancy, just the installation of one or two windows to the roof, allowing natural light into, what once was a dark unused area. Prices can range from £20k – £49k for a standard conversion.

Insulation can dramatically reduce the amount of heat that escapes a property. With the right insulation, more heat will be retained within the property rather than it escaping through the roof. For optimal insulation, it’s worth investing in high-quality materials – such as: 

Rock Wool and Earth Wool at £10/£15.50 per square metre (M2) up to Celotex Board, costing as much as £40/M2. 


One would assume that going to the trouble and cost of converting the loft space, it would be used as a living or recreation space. Therefore, the loft joists would need to be strengthened/stabilised to take the extra weight and prevent sagging. Once this process has been completed, it’s time to choose the flooring material.

There are many different types of flooring materials available, from vinyl, laminates, wood, tiles, Amtico and carpet. The type of flooring will depend on the footfall in that area. A games room, for example, would need hard-wearing flooring like laminate, whereas a bedroom would probably look and feel better if carpeted. Have you allowed flooring in your budget? Measure the loft floor area and then choose the most suitable material for the conditions. See below an average cost per square metre of the different materials. 

Type Average cost per M2
Vinyl / laminates £10 – £35
Wood £20 – £90
Carpet £8 – £60
Tile £20 – £90
A loft conversion may cost as little as £25K or as much as £200K! When considering a complete roof replacement for a semi-detached or detached property, the costs will vary based on the style of the roof.  For example, gable roofs require bespoke services, which range between £7,000 to £15,500. Hip roofs’ are estimated at £8,000 to £17,000. A Mansard type requires up to £45,000. The type of window or glazing you select will affect the cost, much like the roofing material.

Unavoidably, a conversion project of any size will require the use of scaffolding and potentially additional structural support to allow the tradespeople access to the loft area. It will also be needed for the removal of redundant materials from the site, i.e., roof tiles, lagging,  rubble, wood etc. 


To get the ball rolling, engage a surveyor who will turn your loft conversion dream into a working drawing, so you can see what it will look like when completed. The fee can depend on the intricacy and size of the conversion, but as a rough guide, expect to pay approximately 2% of the project cost.

Loft conversion styles with the cost comparison.

With a Velux window/s, you can let in a huge amount of natural light and at the same time be energy efficient. Most of these windows are UV resistant and excellent at keeping the heat in. They are naturally weatherproof, and their airtight seals ensure minimal heat loss.

Prices typically range from £20K to £50K but ultimately depend on how many windows are installed in order to maximise natural light and fresh airflow into your new space! The window can be motorised and have rain sensors as an option. How many times have we left a window open during a thunderstorm? We’ve all done it. A rain sensor will close the window and prevent any water damage.

Transform the potential of your loft space with Dormer Conversions! A flat-roofed extension featuring a window or two offers an opportunity to increase living spaces and create up to four new rooms. Standard dormers range from £31K – £58K, while L-shaped conversions average between £40K – £60K making them the ideal solution for updating any home without breaking the budget. Dormer extensions could be the perfect solution if more headroom is needed. 

You can often maximise your headroom space and unlock a loft’s potential with hip-to-gable extensions! This type of conversion can cost anywhere between £40K -£70K. Take advantage of the unique aesthetic benefits offered by these stylish solutions. 

A Mansard extension is the ideal choice for homeowners looking to transform their property into something special. It involves replacing one side of the roof with a straight wall and adding an entire storey while providing more space than dormers. This kind of renovation requires planning permission but can add significant aesthetic appeal to a property. Cost can vary between £45-75K, depending on the design of your project.

Party Wall Agreement

What about the neighbours? 

They might be affected by your conversion. Don’t overlook the fact that you may need to come to some agreement with them before the project even begins. The Party Wall Act is designed to prevent or resolve any disputes between neighbours concerning boundary walls, party walls or any excavations close to neighbouring properties.

The Party Wall Agreement may add another £1,000 to the cost of your project, which is worth the investment to avoid any conflict with the neighbours; after all, you could be living next to them for many years to come. 

Plan your Loft First!

Starting a loft conversion project can be exciting but daunting at the same time. Therefore ensuring you have engaged the right professionals is important. A structural engineer is essential for calculating the support needed during demolition or extension work. At the same time, an architect will provide comprehensive advice regarding local authority requirements, planning laws etc.  

The project can take lots of time, research and planning to reach the starting point. Well, not really if you engage the Loftconversion team. They will take care of the project’s minutiae, so you don’t have to!


Are you ready to begin your project?

Our Loftconversion team in London have the professional expertise, capability and years of experience you would expect/demand in a professional loft conversion company.

Contact us today and get the ball rolling!

Loft Conversion

Home Extension 


Interior Design 

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