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Double Storey Extension Cost

Written by Kane Hughes

Kane Hughes

Writer

I have been an avid DIY'er for the last eight years now. I combine this with content writing experience to deliver quality content readable by all.

5th November, 2025

How we get our data

We gather our data from real quotes given by UK tradespeople to UK homeowners on the MyJobQuote platform.

At a Glance

The average two storey extension costs £60,000 in the UK.
Double storey extensions up to 14 weeks for builders to complete.

In this double storey extension price guide, you'll find the following:

NEW! A double storey extension cost calculator, which gives you a quick and no-hassle way to get an idea of what this type of job will cost you.
A breakdown of what you can expect to be quoted for different types of two storey extensions in 2025 (includes double storey extension cost per m²).
Expert advice about extensions from builders on MyJobQuote.
How to find and hire a local builder to add an extension to your home.

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Extension Cost Calculator

Average Double Storey Extension Cost:

Depending on the complexity of the job, it usually takes: 10 – 12 weeks

£60,000

How Much Does a Double Storey Extension Cost?
Double Storey Extension Prices
What Is the Cost of Double Storey Extension Labour?
Factors That Impact Double Storey Extension Costs
What Is Involved in Building a Double Storey Extension?
What Are the Benefits of a Double-Storey Extension?
Types of Double Storey Extension
Which Direction Should I Extend My House?
Adding or Extending a Bathroom
Adding or Extending a Kitchen
Double Storey Extension Rules and Regulations
Cost of Double Storey Extension Removal
Checklist: Hiring a Double Storey Extension Builder
FAQs
Sources

How Much Does a Double Storey Extension Cost?

Looking into how much a double storey extension costs in the UK?

If you find that your home has become too small, then a double storey extension could be the right solution. The cost of adding a double-storey extension will vary hugely – the size, complexity and location all play a huge part.

A two-storey extension not only gives you more space, but it is more cost-effective than moving house and cheaper per square metre than a single storey extension. If both storeys in an extension are the same size, then a double storey extension will cost around 50% to 75% more than a single storey extension.

The typical cost of building a two-storey extension starts at around £40,000 but easily run as high as £100,000. The increase in cost depends mostly on the size of the extension but will also increase if you are planning to use some of the space as a kitchen or bathroom.

As a starting point, double storey extension costs per square metre are between £1,500 and £2,500. This is for your basic building materials including foundations, walls, roofing, plumbing, electrics and finishing.

Once you've roughly calculated how much a two storey extension costs based on this, you'll need to add between £5,000 and £15,000 for an average-sized fitted kitchen, and a further £1,500 to £7,500 for a standard family bathroom.

The lower price is for a basic specification — the no-frills essentials — and the top-end price is for the highest quality goods and services, with some custom-made pieces such as large windows, bespoke stairs or hardwood floors.

I have a 3 x 4 m conservatory with three full brick walls and a dwarf wall across the front (3m). My house is built on a raft, is it possible to add a raft to the current building and then convert it to a two-storey to match the back of the house?

"It can be done, but you would need an RSJ beam put in and built up from that. You would need a structural engineer to do the calculations for it. I would say to build the new first-floor walls from timber frames to keep the weight down on the raft."

Nu Rooms

Double Storey Extension Prices

The price you pay for your double storey extension will depend on multiple factors. This includes the finish you choose, your location in the UK, and what your extension will consist of.

The illustration below shows the difference in costs based on your extension size and the specification of finish that you choose.

The tables below show some average costs for extensions in the UK, including the average price per m² and what you can expect to pay if you are adding a kitchen or bathroom to your home.

Note: 30m² would be classed as a small extension; 60m² as medium, and 100m²+ as large.

Small Double Storey Extension Cost

Expense	Basic Specification	Average	High Specification
30m² extension*	£40,000	£47,000	£55,000
Cost per M²	£1,333	£1,566	£1,833
Fitted kitchen	£8,000	£10,000	£15,000
Bathroom	£4,500	£7,000	£9,000
Total	£52,500	£64,000	£79,000

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Medium Double Storey Extension Cost

Expense	Basic Specification	Average	High Specification
60m² extension*	£65,000	£70,000	£75,000
Cost per M²	£1,083	£1,167	£1,250
Fitted kitchen	£8,000	£10,000	£15,000
Bathroom	£4,500	£7,000	£9,000
Total	£77,500	£87,000	£99,000

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Large Double Storey Extension Cost

Expense	Basic Specification	Average	High Specification
100m² extension*	£90,000	£95,000	£100,000
Cost per M²	£1,083	£1,167	£1,250
Fitted kitchen	£8,000	£10,000	£15,000
Bathroom	£4,500	£7,000	£9,000
Total	£102,500	£112,000	£124,000

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What Is the Cost of Double Storey Extension Labour?

Now, let's take a look at labour costs and timescales.

You should obtain at least 3 quotes for the building work, and, if possible, view some work previously completed by the contractor. You will usually find that a cheaper contractor is less skilled, although this isn’t always the case.

When budgeting for building costs, below are the rough charges for one day’s labour by the various work types. For a double storey extension you're going to need to hire a variety of tradesmen or a company which specialises in extensions and covers all areas.

You can break your total extension costs into three constituent parts – the cost of labour, materials, and site clearance/tidying – and gauge roughly how long the building project should take.

	Average 30m² extension	Average 60m² extension	Average 100m² extension
Materials	£16,450	£24,500	£33,250
Labour	£28,200	£42,000	£57,000
Site Tidy	£2,350	£3,500	£4,750
Total	£47,000	£70,000	£95,000
Build Time*	8 – 10 weeks	10 – 12 weeks	12 – 14 weeks

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The build time is contingent on the efficiency of labour, weather conditions and scheduling of multiple work types simultaneously. You should also factor in extra time for complex additions and a larger extension size.

What costs do you incur for house extension work?

"Around £850 per square metre for labour only or £1,550 per square metre with all structured materials included."

Jo Build Ltd

If you need to get planning permission, go to an architect, or gain a Party Wall agreement, you will need to add the relevant time on before the building work begins.

Additional Two Storey Extension Costs

When building a double extension, there may be some additional costs that’ll be worth budgeting for just in case you need any. Here are some average additional costs you might come across:

Type of Additional Cost	Average Cost
Underfloor heating cost	£1,500 – £2,500
New boiler cost	£1,500 – £2,000
Architect fees	£800 – £2,500
Surveyor fees	£500 – £2,000
Certificate of lawful development	£100
Party wall agreement	£500 – £1,000
Planning fees	£200

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Factors That Impact Double Storey Extension Costs

To work out a reasonably accurate budget for your extension, there are lots of factors to consider.

You should always round up any potential costs, and add around 10% as a buffer; otherwise, any unexpected costs can blow your budget.

Planning Stage

This includes every aspect which needs consideration prior to the build.

This includes the design of the extension and creation of full plans, any planning permission or site visits/surveys, project management (whether by an architect or building firm), party wall considerations/approval, and attendance by a structural engineer, including any work he or she deems necessary.

You should budget around £13,000 for the complete planning stage.

As a note, hiring an architect isn’t a legal requirement, but they have been fully trained in all aspects of building design including how best to make use of space, ensuring access, adhering to regulations, and managing the project if required.

If you want your project to go as smoothly as possible, an architect is a good use of your money.

What can I do to keep architect costs down when planning an extension?

"It might be a good idea to look for a smaller, newly founded practice driven by expanding their business; their overheads should be more modest than other, more established practices.

Consequently, you might expect a lower fee whilst professionalism and quality are not compromised."

Bogdan Popa

Initial Building Work

This is the stage where you start having contractors on site, and the build begins. By the end of this stage, you will have a basic shell which then needs work on the interior.

Foundations – Whether you go for a deep strip foundation or a trench fill, you are looking at around £6,000 to make sure your extension is going onto a solid structure. Often, the builder will provide a quote based on an average width, depth and load-bearing ability, but this will change once the ground can be fully assessed.

I am planning on some extension work and have not been able to find out how wide the footings for the foundations will need to be. I’ve been told they need to be 1 metre deep, but not how wide?

"Usually the inner course of block is 100mm then a 100mm cavity then a 100mm outer course plus you need to allow 150mm bearing each side. So in total 600mm. As for being a meter deep, you need to hit good ground, ideally clay!"

Leighs Property Services (NW) Ltd

Framing – There are four main types of framing with their own positives and negatives. Timber framing works out the most expensive as it is custom-built; however, brick and block framing, flat pack/modular, and rapid masonry construction all have their own benefits. Budget around £5,000.

Exterior finishing – Prices can vary wildly under this category. A natural stone finish will cost you around £350 per square metre, as opposed to £40 per square metre for standard cement. An average facing or rendered brick exterior will cost around £3,500 in total.

Roofing – An average roof installation, using standard-sized roofing tiles and standard shaped roof will cost around £4,500. You will need to factor in more for inclusion of chimneys, varying pitches, gables, etc.

Secondary Building Work

At this point, you need to add your access points and any external landscaping (if required) – building work and machinery may have damaged existing green space, and the addition of the extension may have required the removal of an existing patio.

Windows – Standard-sized 'off the shelf' double-glazed windows cost around £600. An average-sized extension may require four windows, which will total £2,400.

Doors – An average-sized composite external door costs around £1,100, including installation. Internal doors, if required, cost from £30 for a basic door, to hundreds for a custom-designed one. On top of this, you will have to factor in the cost of hanging the doors and the fixings.

Landscaping – In most cases, any previously existing patio will have been removed to make way for a rear extension. If you want to have a new patio laid while your extension is being built, you will need to hire a landscape gardener. An average patio will cost around £1,800 for both the materials and labour, but you can calculate the cost for your specific sized patio if you use a basic charge of £100 per m², which should cover both the labour and your materials.

Interior Work

This is the final stage of the build. Your contractors are now looking to wire your extension, complete plumbing work, extend your heating and install your bathroom and kitchen if required.

You will need to have your new walls plastered, and you may then wish to bring in a decorator to add the finishing touches to your new rooms.

Installation of a new kitchen – A small basic specification kitchen and a large high specification kitchen will vary in price by many thousands. However, the average cost of a new kitchen that's medium-sized (with average specifications) is £10,000. This will include all of your appliances, plumbing, electrics, tiling, painting, worktops, cupboards/units, and fittings.

Installation of a new bathroom – As with the installation of a new kitchen, how much you pay for this is significantly dependent on the size and finish. A standard new bathroom costs around £7,000, which will include your bathroom suite, plumbing, heating, electrics, tiling, painting, and installation.

Electrics – Most electricians will charge an average day rate of £230, but the cost will then rise as you decide which fixtures and fittings you want. For instance, a basic single socket costs far less than a double socket with chrome finish and USB ports. The electrician will need to do a basic wire of the extension, and your fuse box may need to be upgraded or replaced. If you have an electric boiler, this too will need to be assessed to see whether it has the capacity to heat the extra rooms or satisfy the additional hot water requirements.

Plastering, painting and decorating – A plasterer will likely quote for the entire job if all rooms need doing, which will be in the region of £700 for a double extension. A painter and decorator will charge around £400 per room. However, how much you pay may drop if multiple rooms need decorating, as the labourer can work on multiple rooms concurrently. You also need to factor in the cost of the paint, so decorating a double extension may end up costing around £1,500.

What Is Involved in Building a Double Storey Extension?

Below is the standard process of a double storey extension build. Ready to get a quote?

You can get multiple free quotes from local extension builders using MyJobQuote, with no obligation to go ahead.

Planning

Party Wall Act (1996) — Take a look at where your extension will be located and research whether you’ll need to consider the Party Wall Act (1996). This sets out a framework to ensure neighbours sharing any wall are given notice of the prospective build and have a formalised method of putting forward any disagreements.
Access, rights of way & insurance — Then consider how deliveries and equipment will be able to reach the work area, any rights of way and whether your current buildings insurance will cover you while the work is done (if not, you can purchase extension insurance).
Planning permission / constraints — Planning permission is a further area to investigate – this will depend on the size and location of your extension, as well as how it fits in with your locale and any implications exerted by the existing building (e.g. if it is a listed building).
Designing the extension — Next, the extension needs designing. Choosing and hiring an architect requires the same amount of research as hiring any other worker, and your architect will then complete all the plans.
Drawing it yourself — If you decide to draw up the design yourself, you may need a draftsperson to help you put your plans into a format suitable for submission to your Local Planning Authority. You may also need a structural engineer to produce information for consideration of a Building Regulations Inspector.
Who will carry out the work — Finally, you will need to consider who will be completing the work. You will need to hire either a main contractor to complete the whole job or subcontractors should you wish to manage the project yourself.
Research your builder — Builders, like any other hired contractor, should be thoroughly researched. You will need to communicate with your builder throughout the project and trust that they will complete the work to the standard you wish.
Can the contractor multi‑trade — It is also worth considering whether your building contractor can do multiple types of work (e.g. plumbing, electrics, brickwork) so it is easier to ensure each piece of work is done at the right time.
Fixed quote & breakdown — If you have researched your project and are able to provide your builder with enough information, they should be able to give you a fixed quote for the work, including a full breakdown of prices.
Building regulations overview — Once you’re happy with your contractors, have your finances in place, and are ready to commence work, the final thing to consider is that of building regulations. These are in place to make sure your property is fire safe, ventilated properly, has appropriate waste/drainage disposal, etc.
Inspections during the build — A Building Inspector from your Local Authority will visit your building site at different stages of the build to check whether there are any problems which may require fixing.

Groundwork

Set out & assess ground — The contractors will attend the site to measure out the foundations, and then a structural engineer will assess the ground and make any recommendations to the builders based on their findings.
Early inspections & clarifications — A Buildings Inspector will visit at this point and make their recommendations, and the architect may also visit to communicate any clarifications to the contractors.
Finalise foundation plans — At this stage, the builders will finalise their plans for the foundations, incorporating the recommendations by the structural engineer and Buildings Inspector and also taking into account any pipes, drainage, etc., which have been unearthed.

Main Build

External structure — Once your foundations have been laid and any drainage issues resolved, the contractors will start work on the external structure. The builders will begin by erecting the external walls and joining the extension to the existing property.
Structure, floors, roof & openings — Then the structural supports, such as beams and columns, will go up, followed by the laying of the ground-floor base and upstairs suspended floor. Finally, the roof will be built, including any dormer windows or chimneys, and the extension’s main windows and any external doors will be installed.
Weatherproof and landscaping — It’s at this stage that the extension is considered waterproof. At this point you may wish to consider landscaping – all heavy machinery, external workmen and scaffolding should now be offsite, so the landscapers can commence their work without risk of damage by the other contractors.
Knock‑through and temporary support — Once your building is watertight, the internal work can begin. The original external wall can now be knocked through into the extension, and a structural engineer will determine what support will be required to reinforce the exposed structure.
Internal frame and joinery — A carpenter/joiner will build the internal frame of the rooms, including door frames and walls. It is at this point that you’ll begin to see the layout and size of your extension, and what each room will look like. Your joiner may, at this stage, also do any custom-building work such as staircases and fitted cupboards.
Electrical and plumbing services — Once this is done, your electrician and plumber can start laying their pipes and wires into the wooden framework. If you are getting a kitchen, bathroom or en-suite installed, the plumber will route your pipework to where you want your sinks, toilets and showers, and your electrician will ask you where you want your light switches, wall sockets and appliances.
Gas engineer (if needed) — If you are having a gas oven or hob, a gas engineer should also attend at this point to install their pipework. After the pipes and wiring have been installed, the plasterer can begin work, and once the plaster is completely dry, the final decorative and installation work can begin.
Joiner returns — A joiner will likely need to return at this point to build door frames, skirting boards, window ledges, and hang internal doors.

The Finishing Touches

Make it suit the house — When you get to this stage, it’s important to think about how your new living area(s) will connect to your existing property. An 18th-century farmhouse may look odd with a new futuristic-looking chrome kitchen, and an exposed-brick rustic bathroom will not suit a super modern house.
Keep finishes coherent — To ensure your new extension adds value to, and complements, your existing property, the look and feel of your fixtures, fittings, white goods, paintwork, cupboards and flooring should all sit happily alongside the existing décor.
Install kitchens, bathrooms & finishes — Once you’re sure of your internal design items, your kitchen and bathroom white goods and cupboards can start being installed, your tiling, painting and decorating can begin, and specialists will lay down flooring and carpets.
Final features and sign‑off — It’s now that you’ll be adding your light fittings, radiators, curtain rails, and other permanent features. At the end of this stage, the Buildings Inspector will return and check that all the work has been completed in alignment with policy and regulations – they will sign-off the work and provide a completion certificate. The workmen will now all leave, and you can look forward to putting your feet up in your new living space.

What Are the Benefits of a Double-Storey Extension?

Aside from cost and duration, here are the main benefits of a two-storey extension.

Space — Adding an extension is a great way to have a bigger home without moving to a different area, and you also save on estate agent fees, solicitors’ fees and stamp duty.
Purpose — Adding your own extension lets you choose the type and size of rooms to fit your purpose. If you have mobility issues, you can get a downstairs wet room; if you’re having a child, another bedroom will be useful; if you’re starting a home business, you can build an office. If you don’t need extra rooms, use the extension to make existing rooms bigger, for example expand the middle bedroom into a main bedroom with en-suite or turn a compact kitchen into a kitchen diner with a utility area.
Pro‑rata cost — A single storey extension adds space, but it costs pro‑rata less to add an extra level because you are already building foundations and a roof. The additional storey mainly needs the internal walls, external finishing and interior finishing.

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Types of Double Storey Extension

You can choose from various types of double storey extension, depending on where or what you want to extend in your home:

Double Storey Front

This type of two-storey extension is most probably the least common. The reason for this is a front extension has the most impact on the look of a property, and there are stricter building regulations to adhere to.

Double Storey Side Return

This type of extension is built at the side of the property without jeopardising the garden area. This extension can be implemented on detached or semi-detached property.

Double Storey Rear

This extends the rear of a property, usually by extending into garden space. This type of extension is a good choice for semi-detached and detached properties. A terraced that has enough back garden space could also have a rear extension.

Double Storey Wrap Around

This type of extension is a mixture of a side extension and a rear extension. If the main reason for you wanting an extension is extra space, then a wrap around extension can add a lot of space to a property and is the best solution. It’s achievable for both detached and semi-detached properties.

Which Direction Should I Extend My House?

When deciding on what direction you should extend your house, you’ll have to take a few aspects into consideration.

The simplest option is extending to the rear of the house, but you’ll need enough back garden space to do so. If you don’t have enough back garden space, maybe a side extension is right for you instead, especially if the neighbour doesn’t have any overlooking windows.

If you want an eco-friendly extension, working out what direction your garden and house faces can help you make a decision. Try to build an extension facing south if possible; this way, it will be warmer and have more light flooding in through the windows.

What you want the space for is also another factor to consider. If you want to extend the kitchen, where does your current kitchen sit within the house? At the back, to the side? What do you want to extend on the second floor? Add another bedroom? All of this will determine what direction you should extend your house.

Adding or Extending a Bathroom

Many families choose to add a new bathroom, refurbish an existing an existing one, or add an en-suite when building an extension. Some also add a WC to their downstairs, as extra washroom facilities will always add value to a house.

The more bedrooms a house has, the more bathrooms are needed so a potential buyer will likely pass on a 4-bedroom house which only has one bathroom, and no WC or en-suite.

A new bathroom, including the suite and installation, will cost between £4,500 and £9,000.

The new suite on its own (bath, toilet, sink) can be bought for less than £500, but your labour costs, cupboards, tiling, decorating, shower, heated towel rail, bidet etc. are what bump up the price. An alternative to a traditional bathroom is a wet room – this is a great option when you need to wash younger children, bath pets, or if you have mobility issues.

These are more expensive than a standard bathroom as the flooring requires plumbing and fully tiling, but they are a modern alternative to a bathroom and worth considering.

Item	Lowest cost	Highest specification
Toilet	£47	£405
Sink	£35	£220
Bath	£80	£650
Walk-in bath	£1,900	£2,000
Shower	£40	£680
Shower cubicle & tray	£170	£500
Bidet	£65	£200

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Adding or Extending a Kitchen

A new kitchen, extension to an old one, or a kitchen remodelling is one of the most popular uses of extra downstairs space, with many families now opting to eat in a kitchen diner rather than a traditional dining room.

A new kitchen can cost anywhere between £8,000 and £15,000, and you could go far higher with enough space and requirements.

If you are extending an existing kitchen, it may be worth replacing any old white goods, so they sit well with new ones, as well as being more energy-efficient and streamlined. The cost of white goods varies as with anything, but below is a rough guide:

Item	Lowest cost	Highest specification
Refrigerator	£100	£2,500
Freezer	£110	£1,750
American-style fridge-freezer	£350	£5,500
Dishwasher	£180	£1,500
Hob – gas	£90	£1,100
Hob – induction	£170	£2,600
Hob – ceramic	£100	£850
Hob – solid plate	£80	£1,500
Oven – single gas	£350	£550
Oven – single electric	£120	£2,200
Washing Machine	£180	£1,700
Tumble dryer – condenser	£190	£1,000
Tumble dryer – vented	£180	£850
Washer dryer	£300	£1,800

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Double Storey Extension Rules and Regulations

Planning permission, building regulations and party wall considerations are the three separate processes, which will need thoroughly researching before you commence your project.

Planning Permission for Double Storey Extensions

Under certain criteria, you don’t need to apply for planning permission – this is covered by householder permitted development rights. There are some caveats and limits, so check what applies to your specific property.

The general guidelines are as follows:

If you live in a national park, the Broads, an Area of Outstanding Natural Beauty, a conservation area or World Heritage Site you are not permitted to build an extension of more than one storey.
All extensions (prospective and previously completed) must not comprise more than half the total area of land around the original house, including sheds and outhouses.
The eaves and ridge height must not exceed the height of the existing house, and eaves within two metres of a boundary must not be higher than three metres.
Double or triple storey extensions must not be more than three metres beyond the original rear wall and must be at least seven metres from the rear boundary.
Roof pitch extensions should match that of the existing house where possible.
The extension’s external materials should closely match those of the existing property.
Upper floor/side-facing windows must not be transparent (translucent is ok) and must be non-opening unless the part to open is 1.7 m or more above the floor in that room.
Under permitted development you cannot add a balcony or veranda to a double storey extension. This would require planning permission.

Double storey extension planning application cost: When you apply for planning permission, it will currently cost you £206, paid to your local planning authority when you submit your application.

The house I've bought already has planning permission for a double storey extension. There's a few little changes I'd like to make to the plans. Do I need to get the plans updated and resubmitted before building starts?

"You would generally get away with internal changes or alterations. However, you’d be better off getting planning or seeking clarification for any external changes so as not get into problems with the council.

So seek clarification or planning before building starts as if spotted by an inspector once building commences, you run the risk of having to pull down any alterations not in line with what has already been approved."

LK Landscaping & Renovations

Building Regulations for Double Storey Extensions

You must check if you need approval prior to commencing your build and should not confuse this with planning permission – you may need both. If the person doing the work doesn’t apply for or comply with Building Regulations, they may be prosecuted and fined, and it will also impact the future sale of the property if the extension doesn’t comply.

You will likely need to submit a Full Plans application, although in some cases a Building Notice is acceptable.
Full Plans applications are typically decided within 5 weeks, or up to 2 months for complex schemes, with your consent.
A completion certificate is issued after the final inspection and paperwork, so timing can vary.
An inspector will do on-site visits periodically to view the work, provide guidance and sign-off approval.

Typical costs: Full Plans around £180. Inspection costs £200 – £550.

In general, is it better to consult with a local authority building inspector or an independent one when you're designing and building a big house extension?

"We would recommend independent inspectors, as if the local authority advise incorrectly there is no action that can be taken against them whereas if independent inspectors advise incorrectly you can take action against them."

Goldline Architectural Limited

Party Wall Considerations for Double Storey Extensions

A party wall is a wall on both your and your neighbour’s land that is part of a building, a garden wall standing on both pieces of land, or a wall used to separate two buildings.

You will need to review the Party Wall Act if you are doing work to an existing party wall, building on or at the boundary of two properties, or are excavating near to or below the foundation level of neighbouring buildings.

If your neighbour doesn’t agree with the proposed work, you and your neighbour must appoint a surveyor together or separately. The surveyors will then agree on a party wall award stating the work, when and how it will be carried out, and who will pay for each part and how much, including the surveyor’s fees.

Typical surveyor rates: £90 – £450 per hour depending on where you live.

Cost of Double Storey Extension Removal

If you have a dilapidated double storey extension attached to your home, you may need it removed. Firstly, you’ll need to hire labourers to demolish the extension. How much this will cost will depend on what size the extension is and how long it takes to demolish.

On average, demolishing a standard-sized double storey extension will cost at least £2,500.

The cost of removing rubble and waste can cost the same, or even more than the demolition itself. You can hire skips (£250 per week, on average) or hire a grab truck to come and collect the waste for around £150-£200. Some demolition companies will offer to take the waste and include it in their overall charge.

Checklist: Hiring a Double Storey Extension Builder

A double storey extension is a huge job! Before you hire someone, there are some things you should consider. Below is a checklist for you to follow when you're searching for double storey extension builder.

Check for any relevant qualifications that you’d expect from that trade.
Ask whether they have liability insurance. Liability insurance would protect you if anything were to go wrong while the work is happening.
Discuss their previous experience. Ask if they have ever completed a job similar to what you’re requesting. Ask if they have any proof or a portfolio of their work.
Do they offer any guarantees? So, if any problems arise in the future, you’ll be covered by a guarantee, and won’t have to fork out even more money.
Enquire if they have knowledge of the planning permission and building regulations regarding double storey extensions.

FAQs

Can I Build a Double Storey Extension Myself?

In short, no, you’ll definitely need to hire relevant tradespeople for certain tasks during the double storey extension build, for example any electrical jobs will need to be signed off by a professional electrician, especially when keeping in-line with building regulations, and this will go for any gas, plumbing, and structural work too. But you can complete some jobs DIY, like painting and decorating, if you don’t mind not having a professional finish, and by doing odd jobs DIY, you can save some money or spend it elsewhere.

How Can I Reduce the Cost of Building My Double Storey Extension?

Keep the design simple to save on specialist or skilled workers, build time, materials and architect time, while staying in keeping with your property. Manage the project yourself and do pre and post build work such as site preparation, sourcing materials and clean up. Speak to your contractors first so your preparation does not complicate or hinder their work.

How Do I Choose the Right Contractors?

Get quotes from several labourers and note how you are dealt with as this shows professionalism and gives you a sense of cost. Check reviews on their MyJobQuote profile and ask to see a portfolio of previous work. A decent and reliable company will answer queries and do a site visit before providing a quote.

Is a Single, Double or Three-Storey Extension Best?

It depends on your circumstances, and a double storey adds space upstairs and downstairs, but a single storey can extend up to 4 metres while a double storey can only extend up to 3 m. Although the final cost of a double storey is larger than a single storey, the average cost goes down so doing both storeys together can work out cheaper. A third storey or loft conversion can add further space while the double storey is built and can reduce extra call out charges and hire.

Will Building a Double Storey Extension Cause Me Any Problems?

With detailed plans, an experienced project manager and competent labourers, issues should be minor, though ground conditions, weather and materials can still cause problems that teams can work around. Problems often come from cutting corners or changing your mind mid build, and extension insurance may help so check your policy. Talk to neighbours early about noise, disruption, access and deliveries and keep them informed.

Should I Move Out While Extending?

If builders need access to most rooms, moving out for a few months helps sanity and timescales, and some companies will not work in an occupied house. A caravan in the garden is a popular option, while a hotel or short term let is quieter and more comfortable but more expensive. Always factor in temporary accommodation cost.

Will My Extension Raise My House’s Future Sale Price?

There is no fixed answer, and the value of your house will almost certainly increase as more living space is a draw to buyers. The sale price also depends on neighbourhood appeal and local values. A £300,000 target will not hold if similar homes nearby sell for £200,000.