Dormer loft conversions are a great way to make your home more spacious, but they can be expensive. This guide will take you through the entire process of planning and building a dormer loft conversion from start to finish. We’ll also go over the breakdown of the dormer loft conversion cost by looking at various factors that can affect your final price tag along the way.
By the end of this article you’ll know exactly what steps to take if you’re considering turning an attic into extra living space!
How much does a dormer loft conversion cost?
The cost of a dormer loft conversion is between £30,000 and £60,000, depending on the size of the conversion, the finish quality, the size of the property, the installation area, and the ease of access.
It’s important to ensure that your conversion is successful and completed to a high standard, and that requires several smaller fees. A master bedroom with an ensuite is likely to cost between £35,000 and £45,000.
Dormer Loft Conversion Costs
Small dormer loft conversions typically cost £2,000 to £7,000, while mid-range dormers would be priced from £10,000 to £30,000.
The cost of a loft conversion can range from £40,000 to £60,000 depending on the installation type and other customisations (roof type, en-suite conversion, etc.), with other factors also affecting the price.
The additional time and materials required for the tradesmen to complete these additions can cause a change in price.
Supply costs
The bullet list below outlines the dormer loft conversion cost for various supply items which will help you understand how the overall quote is calculated.
Loft Conversion Windows
| SIZE (CM) | AVERAGE COST |
| 50 x 50 | £150-£200 |
| 100 x 100 | £200-£250 |
| 120 x 120 | £250-£300 |
Loft Conversion Flooring
| TYPE | AVERAGE COST PER M2 |
| Vinyl | £7-£20 |
| Wood | £10-£70 |
| Carpet | £4-£40 |
| Tile | £10-£60 |
Loft Conversion Insulation
| TYPE | AVERAGE COST PER M2 |
| Sheet | £15-£25 |
| Loose-Fil | £5-£15 |
| Blanket | £12-£27 |
Loft Conversion Stairs
| TYPE | AVERAGE COST PER M |
| Basic | £1,000-£1,200 |
| Custom | £3,000-£10,000 |
| Spiral | £1,000-£1,500 |
| Alternating Treads | £350-£750 |
| Fixed ladder with Bannister | £150-£400 |
General Building Materials
| MATERIAL | AVERAGE COST |
| Electrics | £300-£600 |
| Structural beams, joists and masonry | £1,500-£4,000 |
| Bathroom | £4,500-£6,000 |
| Decorating materials | £800-£1,600 |
| Built-in Storage | £1,500-£10,000 |
Labour cost for Dormer Loft Conversion
There will usually be 2-3 people on-site during any large-scale project.
The timescale may be varied in order to accommodate all the tradespeople, and it may also be affected by the weather.
| TRADESMAN | AVERAGE COST PER HOUR |
| Builder | £20-£35 |
| Tiler | £20-£40 |
| Plumber | £35-£45 |
| Electrician | £50-£120 |
| Plasterer | £30-£50 |
| Decorator | £20-£50 |
Cost Factors of a Dormer Loft Conversion
The cost of a dormer loft conversion depends on broadly two factors, including:
- The size of the loft and materials used. A larger dormer loft conversion will cost more to build than a smaller one. For example, if you want your new bedroom to have an en-suite bathroom, you’ll be looking at an even greater expense.
- Location of building. If you live in a central area where land rates are higher than other parts of the country (especially for commercial properties), this will also affect your dormer loft conversion costs as quoted by builders or renovators.
Process involved in a dormer loft conversion
After the initial survey and design meeting, you’ll have a clearer idea of what work is involved in your loft conversion and what it will cost.
The works are usually carried out over six or seven weeks, depending on the size of your property, including:
Week 1
The roofing contractors will assemble the scaffolding before the roof is opened. Materials will be collected on-site for this job.
Week 2
The structure of the roof might require additional supports if the structure is being altered. Windows will be installed if a roof light conversion is being performed. A dormer will be built if a dormer conversion is being performed.
Week 3
Any external work such as painting walls will be finished off including the tiles replacements and finishing.
Week 4
Fixing windows into place if required by local authority building control regulations prior to installing wooden frames for dormer floor levels (minimum size 600mm x 800mm).
The glazing must be approved by an independent surveyor at this stage as well as fireproofed between floor levels with insulation boards etc., fitted if required by local planning department requirements before erecting any further internal wall partitions or partitions within existing rooms.
Week 5
Installing staircase into new bedroom area; installing bathroom facilities; fitting taps, showers etc.; plumbing in new lighting fixtures throughout.
Week 6
Any unfinished jobs will be completed during this week. If your contractor is responsible for the decoration, that will occur this week. The scaffolding will be removed during this week as well.
The given timetable outlines the perfect scenario, showing the minimum time required for each stage and assuming no delays.
Types of Dormer Loft Conversion
When it comes to dormer loft conversions, there are a number of factors that will determine the type of conversion you need. These include:
- The type of house (terraced, semi-detached or detached)
- The existing roof shape
If you have an existing terraced or semi-detached property with a flat roof then you should be able to carry out a simple dormer extension conversion with little disruption and minimal costs involved. A similar situation applies if your house has an already flat roof but it is pitched in such a way that creating enough space for your new bedroom is not possible without removing some original walls or floors.
Flat Dormer Roof
A loft is a great place for a bedroom, office or playroom. If your home has an attic space that’s too small, you can convert it into a flat dormer roof. This provides a fairly simple way to expand the usable space in the loft for little cost and effort.
If you have a single-sided dormer (see diagram), removing some or all of the existing roofing will make it possible to create an entirely new room with windows on three sides that overlooks your garden below.
Adding insulation between joists and skirting boards will increase comfort levels during winter months and reduce noise levels at night when you need peace and quiet after work
Gable-Fronted Dormer
Are you thinking of converting your attic into a more useful space? If so, then a gable-fronted loft conversion would be a good choice.
A dormer loft is designed for people who want to make their attic bigger, but don’t want to lose any headroom. Dormer lofts are great for sleeping or relaxing in; they can also be used as home offices or playrooms.
Hipped Roof Dormer
If you have a hipped roof, and want that same open loft space feel, the easiest way is to convert your dormer into a skylight.
This is an aesthetically pleasing look that will give you plenty of natural light and improve air circulation in the room.
The only issue with this is that it doesn’t create much headroom – so if you’re planning on using this as an extra bedroom or office area, it may not work for you!
L-Shaped Dormer
The L-shaped dormer is an extension that consists of two dormers that are connected at right angles to each other. This type of loft conversion helps maximize the space within your home, as it can be used to create multiple rooms.
The dormer can be positioned at either the front or back end of your property, depending on whether you want more natural light in a particular area or want more privacy for your new room.
Dormer Loft Conversions DIY
A loft conversion can be one of the most exciting and achievable DIY projects, provided that the job is fairly simple and the loft will mainly be used for storage rather than as a full living area.
It is imperative to hire a professional for a high-quality and safe loft conversion if you want a dormer or want to add extra windows.
However, there are several tasks that you can do yourself to save money on hiring contractors and to really make the project your own. The first step is fitting the flooring, assuming you have all the relevant permissions and paperwork in place.
If you already have decent wooden floor beams, this step is fairly simple since all you need to do is fill the spaces between the beams with insulation, then lay floorboards across them.
After the studs are positioned, the walls are covered with plasterboard and held in place with nails or screws.
It’s a bit more difficult to plasterboard angled loft walls. Once the plasterboard has been tacked in place, you should seek out a plasterer for a professional finish.
It is best to leave any extra finishing or installation work to a professional, who will be able to complete the conversion to a high standard.
However, if you choose to go ahead with your own dormer loft conversion plan, it will be beneficial to have a contractor verify that it is doable.
Planning permission and building regulations
In England, the fee for getting planning permission when converting a house is £172.
Building regulations may also be required to ensure that your conversion adheres to existing local regulations. The cost for this will depend on the project’s size and complexity and typically ranges from £400 to £800.
You will require a surveyor and a legal professional to create a Party Wall Agreement if you share a wall with a neighbour. In this, you will get permission from the owners of surrounding properties to go ahead with construction on the walls that you share.
Surveyors’ fees can range from £150 to £200 per hour, and a party wall award (included with a surveyor) can cost upwards of £1,000.
Architectural plans for a conversion can range from a simple set of plans for £400 to a more detailed set for up to £1,500.
Allocating all of those permissions and mapping out all of your plans can take weeks, depending on how extensively you are hiring workers. You must consider the pre-planning in your conversion timeline.
Dormer loft conversions are allowed by law, but you do need to make sure that the work is done properly. In order for your conversion to be approved, it will have to be compliant with building regulations and planning permission.
It’s important that you get the correct guidance from an experienced architect or builder before starting work on your dormer loft conversion as this will ensure that you don’t end up paying for unnecessary costs later on in the process.
There are three main permissions which govern dormer loft conversions: Planning permission, building regulations and building control.
What to look for in a good builder
When choosing a builder, you should look for someone who is experienced in loft conversions. They can help you to understand the process and how long it will take, as well as give advice on how many people will be needed for the job.
You should also choose a builder with a good reputation. You’ll want someone you can trust, so make sure to check reviews from past clients before making any decisions.
Good communication is also essential when working with builders. They will need to communicate all aspects of your project clearly and effectively, as well as respond promptly whenever there are changes or issues that need addressing.
The ability to manage expectations is another important skill for builders; they must be able to accurately predict costs and work schedules so that both parties are aware of what’s going on at all times throughout construction work.
To sum up, it’s important to consider all the costs involved in converting a dormer loft. However, if you have the right contractor and follow their instructions carefully, then there should be no problems with your conversion.
Get in touch with our professional roofers at Premier Roofing Solutions if you need help with any loft conversion projects.
