Costs & Guides

We’ll go over the various costs of building a granny annexe in this article, including supplier costs, additional charges, and tradespeople costs.
If you’re considering building a granny annexe, you’ll find everything you need to know right here!

How Much Does It Cost to Build a Granny Annexe?

Multi-generational households have become more widespread in recent years, either as a result of adult offspring remaining at home longer or as a result of elderly relatives requiring additional care.

One of the most typical options for such families is a prefabricated granny annexe. It can also be one of the most cost-effective choices if you choose the right service or function.

If you’ve reached a point when you’re concerned about the health and well-being of a loved one, you may be presented with the same choice. A granny annexe is a terrific way to keep them close while also allowing them to live independently.

Building a granny annexe might save you money on care homes and the guilt and stress that comes with having an ill or elderly relative live alone.

You are welcome to check in on them on a daily basis and assist them with duties such as cleaning and personal hygiene. You may even invite them over for dinner later in the evening. A safe, comfortable, and unique place is provided by a granny annexe.

If you decide to build an annexe with independent contractors, you’ll need to budget for an architect, as well as the materials and labour required to finish the job.

Many of these charges are bundled together with prefabricated annexes, especially when employing a turnkey service like ours. You can save money, time, and stress by doing so.

A granny annexe is a separate dwelling that includes a bedroom, bathroom, kitchen, and living area. As a result, the project is not cheap. In your budget, make sure to include both construction and furnishings & fittings.

Building a granny annexe costs between £80,000 and £100,000, whereas purchasing a granny annexe kit costs between £29,000 and £51,000.

You could also convert your garage into a granny annexe for £7,500 – £20,000, or a loft conversion for £37,500 – £60,000, or a basement conversion for £100,000 – £160,000.

You’ll also need building regulations, which will add £200 to £500 to your overall cost, as well as utility diversions or works, which would cost £4,500 to £5,000.

Granny Annexe Prices

The table below shows the various costs of adding a granny annexe to your property.

Job	Cost
Cost to build a granny annexe	£80,000 – £100,000
Granny annexe kit	£29,000 – £51,000
Garage conversion	£7,500 – £20,000
Loft conversion	£37,500 – £60,000
Basement conversion	£100,000 – £160,000
Building regulation	£200 – £500
Utility diversion or work	£4,500 – £5,000

What are the Supply Costs to Build a Granny Annexe?

While it’s tempting to save money on labour, the last thing you need is a dangerous and structurally unsafe annexe.

This decision is mostly based on your degree of knowledge and experience; nonetheless, you’ll need to know what you’ll need to build a granny annexe, so we’ve created a section that only contains supply costs and excludes any additional or labour charges.

To begin, you’ll need planning approval to ensure that building a granny annexe in your home or garden is safe and legal. The cost of submitting a planning application varies by location in the United Kingdom.

In England, a full application or outline planning permission for a new single dwelling costs £462. A householder application costs £206 in England.

To begin, you’ll need to ensure that your granny annexe has a stable foundation by purchasing pressure treated timber posts, which range in price from £24 to £136.

Before you buy, you’ll need to know what size you need. A shovel will also be required, which would cost between £7 and £25.

Premixed concrete will also be required, which would cost between £6 and £13 depending on the amount required. To keep the granny annexe warm, you’ll need to purchase insulation. This costs between £19 and £49.

You’ll need to purchase windows, which range in price from £129 to £400 depending on the kind, and a door from £40 to £600.

Plumbing on your property delivers water and removes trash, and it helps to make your house a home. Building a house from the ground up requires a lot of effort and money. In a new home with one main bathroom and one en-suite, plumbing costs between £13,000 and £15,000.

This includes the time and effort required to install additional plumbing throughout the property and connect it to the property’s major utilities (water, drainage, and sewerage) as needed.

A new energy supply connection costs between £1,600 and £2,000 on average. Charges may be much more or lower based on your specific circumstances.

Then you’ll need to acquire everything for inside your house, including décor, furnishings, toilets, showers, and other items that will need to be installed after the granny annexe is built.

The table below shows the various supply prices for constructing a granny annexe on your own.

Supply	Cost
Planning permission	£206 – £462
Pressure-treated wooden posts	£24 – £136
Shovel	£7 – £25
Premixed concrete	£6 – £13
Insulation	£19 – £49
Windows	£129 – £400
Door	£40 – £600
Plumbing	£13,000 – £15,000
Electricity	£1,600 – £2,000

What are the Additional Costs of Building a Granny Annexe?

When it comes to establishing a granny annexe for a family member or friend, there is a lot more to it than you might imagine.

As a result, when having one made, you may discover that there are numerous additional charges. As a result, we’ve produced this section to help you understand what extra expenditures to anticipate when developing your granny annexe.

New Kitchen

If you want a tiny kitchen put in your granny annexe, you’ll have to pay extra because the compact home already has a kitchen. But how much does it set you back?

The size of the area and the materials you choose impact the cost of a kitchen remodel. A basic kitchen with only the most essential kitchen components costs between £4,000 and £10,000, with average kitchen prices ranging from £5,000 to £12,000.

Your granny annexe will only require a modest to medium-sized kitchen. Kitchens with seven or fewer components range in price from £4,000 to £15,000.

The average medium-sized kitchen has ten items and costs between £6,000 and £17,000.

Kitchen installation expenses include the cost of flooring. If you want a new kitchen floor, expert installation of kitchen tiles would cost between £60 and £75 per square metre.

You might wish to hire a professional painter and decorator to finish the walls in your kitchen.

This might entail painting your kitchen walls, which can cost anywhere from £300 to £500 depending on the size of the area.

For more information, please see our cost of a new kitchen guide.

New Bathroom

In your granny annexe, you’ll need to install a new bathroom. A basic grade bathroom might cost anything between £1500 and £2000 to install.

A bathroom of average quality will cost between £3,000 and £6,000, whereas an extraordinary bathroom will cost between £7,000 and £15,000.

A simple bathroom installation might cost anywhere from £1,000 to £3,000. A medium-sized bathroom is expected to cost between £3,000 and £6,000.

You’ll also need to purchase everything for the bathroom, which means a new toilet will cost between £100 and £200 and a shower would cost between £40 and £500.

A new shower screen will cost between £50 and £150, a new bath between £100 and £400, a new sink between £50 and £200, and new bathroom taps between £40 and £100.

For further information, please see our guide on the costs of a new bathroom.

Painting and Decorating

After your granny annexe is constructed, you might consider painting and decorating it to give it a homey feel.

You should consider how much interior painting will cost for various services while remodelling. For example, painting a room can cost anything from £180 for a small bedroom to £600 for a huge living room.

Other fixtures, such as skirting boards, which cost between £180 and £350, and window painting, which costs between £400 and £1,500, should be factored into the painting and decorating budget.

Wallpapering can cost anything from £180 for a small room to £600 to strip and hang, while internal cladding can cost anywhere from £1500 to £2500.

Because most tradespeople charge by the hour, understanding how long a job will take to determine the final price is also critical.

It should only take a day to paint a small one-bedroom granny annexe; however, if you need any wallpaper or paint removed, you’ll need to add another day.

Floor Installation

In most cases, the cost of flooring installation ranges from £400 to £1,000. The cost of installing new flooring, on the other hand, is dependent on the type of flooring and the size of the room.

Carpet is a form of textile carpeting that is often composed of wool, nylon, or polyester and costs between £90 and £900 on average. Laminate flooring is a modern synthetic floor that mimics more expensive flooring materials such as wood and stone. The cost of installing laminate flooring normally ranges from £170 to £800.

Many solid wood species, such as white oak, maple, beech, red cedar, and others, are used to make hardwood flooring. Timber flooring installation costs range from £550 to £1,750. Vinyl is similar to laminate flooring, except it is totally constructed of synthetic materials including fibreglass, PVC vinyl, and plasticiser.

Vinyl flooring installation costs typically range from £90 to £450. Installation of tiling costs between £400 and £1,380, karndean flooring costs between £600 and £2,400, and parquet flooring costs between £200 and £2,500.

Plastering

Because plastering a home takes time, the majority of the costs are labour. Plastering a room might cost anywhere from £300 and £900.

Plastering two average-sized rooms will cost between £400 and £600, with little patch repairs costing between £100 and £200.

The size of the area to be plastered, the condition of the area, and whether or not plasterboards are required are all factors that might influence how long a plastering job takes.

You must also consider whether only skimming is necessary, any trash removal jobs that may be necessary, and your location in the United Kingdom. Plastering a house, on the other hand, can take anywhere from 3 to 4 days.

New Radiator

Installing a single panel radiator should cost between £110 and £210, a double panel radiator should cost between £140 and £240, a horizontal radiator should cost between £260 and £470, a vertical radiator should cost £280-£440, a column radiator should cost £290-£470, and a heated towel radiator should cost between £130 and £230.

A new radiator installation will cost between £30 and £70 per hour, with a day fee of roughly £240 to £320. However, your location in the United Kingdom will have a significant impact.

Minimum Fee

Workers may choose minimum pay in a variety of circumstances. On the one hand, this might be a one-time cost that is applied to your entire payment. In some cases, though, it may be utilised to extend a current charge.

Consider the situation where you are paid on a daily basis. You would be charged for two days of labour in this example, whether the job took one day and three hours or one day and seven hours.

Location

Because the cost of hiring a builder differs by region, where you live has a significant financial impact. The southeast, particularly London, has greater labour rates than the rest of the UK, whereas Scotland, Northern Ireland, and the north of England have the opposite situation.

Duration

The longer it takes on-site due to labour expenditures, the more you will pay. If labour is taxed per day, whether the work takes two days and three hours or two days and six hours, you will be charged three days of labour.

The labour cost will not be impacted by the passage of time if a fixed price is agreed upon ahead of time.

Tradesmen Costs for Building a Granny Annexe

You’ll almost probably need the services of a builder for construction projects and structural work (or builders).

We’ll go over the labour costs for building a granny annexe without any supplies or other fees so you can see how much money you’ll save by doing it yourself.

For a tradesperson to build a granny annexe, you should budget between £150 and £280 every day.

The amount you pay will be determined by the individual’s experience, the project’s complexity, and your geographic location. In London and the Southeast, for example, builder day rates are higher.

Self-employed people can expect to get paid around £25 per hour.

Working as a self-employed individual versus working for a construction company differs in that self-employed individuals typically charge a cheaper hourly rate because they are not responsible for the administrative and overhead costs of a larger corporation. This, however, will depend on your previous experience and where you are in the United Kingdom.

As with other experts, we normally recommend receiving at least three quotes from different builders in your area. You should shop around to make sure you’re getting a fair and competitive deal on the job.

For the water and sewage work, you’ll also need to engage a plumber. It depends on the size, complexity, and/or difficulty of the plumbing project.

Sinks, toilets, and other plumbing components that are difficult to reach or that must be disassembled and reassembled later will take longer, resulting in higher costs.

Plumbers often charge between £20 and £40 per hour. The total cost, however, will vary depending on the job’s scope.

The lights and plug sockets in your granny annexe will require the services of an electrician. In most cases, you may expect to pay between £280 and £450 for this service.

However, for other jobs, we’ve had quotes as low as £150 per day. Expect to pay roughly £75 per hour for an electrician in London. The cost of an electrician in the south of England will be slightly more than in the rest of the UK.

How Long Does It Take to Build a Granny Annexe?

Granny annexes are gradually gaining popularity as a viable alternative to today’s affordable housing issues. They’re perfect for downsizing and freeing up equity, as well as retirement planning and elderly care (granny flats).

Here, we’ll go through how long it takes to build a granny annexe so you know when your project will be finished and your family or friend will be able to move in.

The decision to build an annexe is undoubtedly the most difficult because it typically involves many or many members of your family to collaborate on how it will work.

With financial considerations like as inheritance tax, council tax, operating costs, transfer fees, and more, the process is not one to undertake lightly. On average, it takes two months to decide what you want.

When you’ve decided on a company to build your annexe with, you’ll usually have to pay a deposit or a planning fee before proceeding to the next stage, which is the important Planning Permission stage. This takes roughly ten weeks on average.

The stages below will lay the groundwork for your annexe’s foundations and essential service connections. This process normally takes 1-2 weeks, depending on where your services are located, the amount of ground preparation required, and the overall size of your annexe.

From the erection of the frames, windows & doors, roof & cladding outside to the installation of the bathroom & kitchen, flooring, plumbing, electrics, painting and décor inside, the average on-site build takes 7-14 weeks, depending on the size and specification of the annexe.

The time it takes to create a granny annexe is broken down in the table below.

Process	Duration
Decision making	Two months
Planning permission	Ten weeks
The foundation and services stage	1 – 2 weeks
Average build	7 – 14 weeks

Types of Granny Annexe

If you’re trying to decide which form of granny annexe to get, we’ll go over the different types of granny annexes and their benefits and drawbacks.

As a result, if you’re undecided about which granny annexe to get, maybe this section of the post can assist you.

Traditional Granny Annexe

A traditional Granny Annexe is a structure that separates a portion of the main house from the rest. This component of the house will have a self-contained living area with a kitchen and bathroom.

They may have separate entrances or share the main door, but they are virtually always attached to the structure and on the ground floor.

Large properties with extra room or gardens that can support the extended structure are ideal candidates.

Pros
+ The apartment is on the ground floor.
+ Your home is connected.
Cons
– There isn’t much room.

Granny Flats

A granny flat is a spin-off of the traditional granny Annexe. In heavily populated city areas, one level of the building may be dedicated to becoming a self-contained flat rather than an expansion attached to the residence.

It takes up one level of a family home, as is usual in cities like London where space is restricted. Because there isn’t much room for an expansion, this option is great for families that want to stay in their current house.

Pros
+ Feels more like home.
+ Have some independence.
Cons
– Expensive

Ancillary Building

An off-site or on-site construction of this style of annexe is possible. The idea is to build a semi-permanent or permanent mobile home in your yard.

The auxiliary structure should be connected to the main house’s utilities. There are various instances of outhouses that have been modified for elderly use.

This type can also be constructed from an outhouse that is no longer in use. If your outhouse isn’t being used, it could be converted into a granny annexe. Even the most basic surroundings can be turned attractively, and even the most modest constructions have potential.

Pros
+ Can build in your garden.
+ Connected to main house utilities.
Cons
– Expensive to build.

Prefabricated Annexe

You can also buy a prefabricated granny annexe. There are a variety of options available, and some companies even let you construct your own annexe.

A prefabricated annexe is delivered to the job site with all of the essential fixtures and fittings. The average cost of a prefabricated granny annexe is between £40,000 and £40,500.

Pros
+ Can design it by yourself.
+ Create exactly what you need.
Cons
– A company is best to build this type.

Benefits of Building a Granny Annexe

If you’re undecided about creating a granny annexe, this section of the article can help you decide.

More Time with Your Loved One

Finding time to visit or take an elderly parent out might be challenging with already hectic schedules. When they’re closer, it’s a lot easier to spend time with them, whether it’s for supper or just chatting in the garden.

Sensible for Financial Reasons

Your loved one is unlikely to be eligible for council-funded care if they have more than £23,000 £24,000 in savings. Downsizing to an annexe in or adjacent to a child’s house, for example, could be a reasonable option in these situations.

The money from the sale of an existing property can be used to pay for the care of a loved one. It also makes additional caregiving chores considerably easier for families, eliminating the demand for professional caregivers.

More Independence

Moving your loved one into a care facility is significantly more difficult than making their living arrangements feel like home and giving them a greater sense of independence.

Security

Living in a granny annexe in the back garden with family members in the main house may make your relatives feel safer, while the annexe allows them to maintain some freedom.

Our clients appreciate knowing that their family is close by in the event of an emergency. Our clients are also more relaxed because they are in a familiar environment for a longer period of time, giving them more stability and peace of mind.

Property Value

A granny annexe will almost certainly increase the value of your home. Although it’s tough to put a precise number on the increase, your local real estate agent is the best person to consult.

How Much Does It Cost to Remove a Granny Annexe?

If you have a granny annexe and wish to get rid of it to make room for storage, you should first figure out how much it will cost to remove it. We’ll go through the various costs of removing a granny annexe from your property here.

The cost will be determined by the materials used to create the granny annexe, as well as any extenuating conditions, such as the usage of banned or hazardous materials. The sort of base it sits on, as well as the complexity of removing it, will influence it.

If you deconstruct it yourself, the expense of removing deep-seated and/or dangerous things could range from a few hundred pounds to several thousand pounds.

A granny annexe removal costs around £200 on average. Expect to pay an extra £200 to £1,350 on top of the removal price if asbestos must be removed.

You should also consider whether you’ll need to hire a skip for the removal. A 2-yard skip will typically cost between £70 and £100, while a 4-yard skip will cost between £100 and £160, and a 6-yard skip will cost between £120 and £190.

A 8-yard dumpster will cost between £150 and £370, a 10-yard skip would cost between £180 and £410, and a 12-yard skip will cost between £220 and £450.

A 14-yard skip will set you back £230-£460, a 16-yard skip will set you back £240-£480, an 18-yard skip will set you back £280-£500, and a roll-on roll-off skip will set you back £300-£500.

As a result, the size of the granny annexe being removed will be determined by the total cost of the removal.

FAQs

Q: What is the maximum size of a granny annexe?
A: If you’re considering building a granny annexe in your backyard, there are a few simple tests you can perform to ensure you have adequate space and that your project complies with LPA and other granny annexe rules.

Although LPA criteria differ by region, one factor they will consider when granting planning permission for your annexe is the size of the proposed annexe in relation to your existing home and the land or garden it surrounds.

Q: Does a granny annexe require planning permission?
A: A granny annexe is a form of outbuilding that is described as being unrelated to the property’s core use. This means that granny annexe developments will not require planning permission.

Q: What are the drawbacks of constructing a granny annexe?
A: While a granny annexe can allow greater independence than a care facility, moving into a child’s yard can be demoralising for a parent, and it may not be appropriate for them.

Q: Does a granny annexe add value to your home?
A: In most cases, a granny annexe will greatly raise the value of your home.

Whether used as additional living space, an office, a home gym, or a vacation rental area, granny annexes provide multi-functional living spaces that can increase the value of a home.

Q: Is a granny annexe subject to council tax?
A: Granny annexes are normally exempt from Council Tax, or are subject to a reduced rate if they are.