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A Comprehensive Guide on Buying a Home for an Annexe

Amid the current cost of living crisis, we often hear about the various benefits of building an annexe; they add property value, create additional living space – and residents share the burden of rising bills with the main dwelling. It’s no surprise then that people are increasingly looking to purchase a home solely based on how viable development plans are down-the-line.

However – with so many rules, regulations and differing planning policies flying around; it’s easy to overlook something crucial. Fear not though, with this comprehensive guide from iHus, you’ll understand exactly what to look for when buying a home for an annexe.

1) Budget

As with the purchase of any property, the first thing you’ll be wanting to examine is your available budget; however – when looking for a house to accommodate an annexe, these costs will need to be factored in as well. On average, it’s estimated that it will cost between £68,000 – £140,000 to build a standard-sized annexe in the UK; though this figure will depend on various factors – such as the complexity of your design and the quality of materials used.

During this stage, it’s vital to assess what your annexe will be used for; as this will undoubtedly have an impact on the price of the build. Two-bed garden homes – for example, inevitably have a larger footprint than single occupancy ones; and therefore would incur greater construction costs. While adding an annexe increases your property value down-the-line; building one is a significant investment. As such, it’s essential you factor in these development costs when establishing your budget for a potential property purchase.

2) Location

Location is often a huge determining factor in a new property purchase; however – when it comes to buying a home for an annexe, there are additional things to bear in mind. Regulations differ greatly between Local Planning Authorities (LPAs), so it’s worth researching how stringent they are in your desired area. Groups such as the National Annexe Planning Consultancy (NAPC) – who have dealt with 80% of all LPAs; have a wealth of industry knowledge to advise with.

Certain locations will inevitably face greater hurdles than others. For example – if the home is situated within a Green Belt, Area of Outstanding Natural Beauty (AONB) or Conservation Area; any potential development must protect the heritage value and landscape of its surroundings. While this doesn’t make annexe construction impossible, it does add another layer of complexity to the planning process. Extra attention will need to be paid to the size and design of the build – as these factors face greater scrutiny in protected locations. With many councils restricting the number of developments on a dwelling; those on Green Belt land – in particular, may find gaining a Certificate of Lawfulness the best route to go down.

Planning writing

Listed Buildings face similar issues; but – with careful design and planning, it’s still possible to gain successful planning results. In these cases, our planning experts would provide a ‘Planning and Heritage’ Statement to support your application; and work with Council and Conservation Officers to achieve the desired outcome. Furthermore, areas of archaeological interest – or that are especially prone to flooding; will also likely require additional reports in order to gain successful results.

3) Accessibility

Selecting a location with access to all the shops, services and other amenities you might need; is essential for any property purchase. However, when it comes to buying a home for an annexe, there are often several other factors to consider. For example, those wishing to house an elderly relative; may find a location that has a hospital or in-home care provider close by, more preferable.

In terms of access to the development itself – it’s always best to keep existing arrangements the same; as councils tend to resist anything that can be accessed independently. Eliminating this factor from your planning proposal – and opting for a property that can already accommodate your access needs; is recommended for a simpler process.

Furthermore, it’s worth noting that some councils have parking standards that require a property to have a designated number of off-street parking spaces. This is dependent on the number of bedrooms on the property; and – as an extension to the main dwelling, will include any added through annexe construction. As such, it’s a good idea to check if the LPA in your area has such standards in place before committing to a purchase.

4) Size

As a rule, no annexe should exceed 50% of the property’s residential curtilage; as this would classify as overdevelopment of the plot. Other external buildings – such as garden sheds and summer houses, also factor into this limit; further reducing the potential scale of future developments. As such – when buying a home for an annexe; it’s crucial you ensure there’ll be sufficient room to accommodate it. However most people assume they’d need a large garden to house an annexe, which isn’t always true.

Councils also require that all outbuildings be subservient to the existing dwelling they’re constructed on. As a result, it’s important to consider the height of your proposed build carefully. While not impossible, planning permission is difficult to acquire for multi-storey annexes; due largely to the impact they have on neighbouring properties.

While there’s no set rule determining it, proposed developments should generally be considerate of those in the surrounding area. As such, it’s crucial that any potential annexe construction does not not interfere with a neighbour’s right to privacy – or substantially block their access to light. At iHus, all of our annexe designs are single-storey; meaning they’re less likely to encounter these issues during the planning process.

Listed are LPAs we have previously gained approval in – as well as the average size of constructions in each.

5) Space

When looking for a house suitable for an annexe, there are plenty of considerations to make about the physical space your development will inhabit. For example, opting for a house on flat land could save up to £2,000 in construction costs; as the plot will not need to be levelled before building. You’ll also want to ensure your chosen site isn’t hard up against any boundaries on the property; as it will need sufficient space to be maintained throughout its lifetime.

Furthermore, annexes also need to be sited within residential curtilage – and therefore cannot be situated on any external paddock or farmland. In fact, many LPAs tend to look more favourably upon developments situated as close to the main dwelling as possible; so it’s worth taking this into consideration when planning your build’s location.

Viewing plans

While constructing an annexe in the front garden is technically possible; gaining planning permission in these cases is notoriously difficult. For a far simpler process, it’s best to plan your development in the rear garden from the offset. Not only does this protect views from the street scene; it also strengthens the argument that the building is ancillary to the main property – as it would not be accessible from the roadside.

6) Design

When it comes to designing your garden home, it’s worth bearing in mind that LPAs will want to ensure your development is in keeping with the character of its surrounding area. As such, design and colour of features such as exterior cladding, roof tiles and fenestration should reflect this; and integrate the annexe seamlessly within the garden context in the process.

It’s also worth keeping this in mind when budgeting your build, as certain areas may require more expensive materials to achieve this than others. Our annexe designs have a number of pre-set customisation options available at the same price; thereby making this process simpler, more streamlined – and easier to achieve.

iHus: Annexe Professionals

Here at iHus, we take care of your entire annexe journey for you and have so much to offer you whilst we hold your hand throughout the entire process. Whether that may be in the form of complimentary advice and resources, such as a feasibility study on a plot you’re interested in, or simply advice whilst you’re at the very early stages of research; you can rest assured our team are here to guide and support you throughout. Here’s a brief summary of everything we cover as part of our standard iHus procedure, or as we like to call it, our Signature Move process.

Signature Move

Our unique Signature Move process makes your annexe journey stress free right from the get go. From your first phone call with us, to your virtual consultation and beyond; our expert team offer a breadth of knowledge in annexe living and construction; you’ll know you’re in the safest of hands whilst our professional team take care of each part of your new and exciting journey.

There are 4 key stages to our signature move process. Step 1 entails your initial complimentary virtual consultation, where you meet with our annexe specialist to discuss your entire project. Our expert will get to know you, understand your requirements and shape the most idyllic annexe home for you, taking into consideration both your needs, and aspirations. We’ll also get to know the details of your garden plot, and your budget so that they can plan ahead and provide you with the most sounds advise possible. Once our expert has a thorough understanding of your individual requirements, we will prepare a completely personalised quote and proposal for you to consider.

The next stage involves planning permission, which again, is something that our experts take care of so there’s no need to delve into, what can sometimes be, a very lengthy and complicated world. With iHus, there’s no need to appoint an architect or planning consultant as we take care of your entire Annexe journey, so you don’t have to. 

If you’re looking to buy a house to add an annexe, we offer a feasibility study which takes a look at the plot that you are interested in and provides a detailed assessment on the local area to help gain an understanding in to how likely we are to be able to pass planning for that particular plot, which really helps you to guide your decision of where to buy. And with a current planning success rate of 93%, the odds of us approving your project for you are in your favour. We’re so confident in our service, that we offer a copper-bottomed money back guarantee.

Your assigned customer liaison will be there by your side throughout your entire journey, to answer as many questions as you may have, call to check everything is running as smoothly as you’d like, and to update you on key steps throughout the process. We understand that this is a big decision to make, therefore we also offer a special 12 month* price lock guarantee on your quote. Our world-class project management will look after your project from the moment your your build starts, right through to receiving your keys.

We believe that aftercare is a fundamental part of our service, so we ensure that you are looked after not only throughout the build, but beyond also. Our iHus handyman can be with you on the day you move in to ensure everything is perfect in your new iHus, and a representative will drop by with a move in gift and ensure everything is okay. Not to mention, we offer a 10 year guarantee on our annexes, and complete a snagging visit at around 6 months too.

Talk to our friendly and experienced team today to see how we can help give that space in your garden the new lease of life it deserves.

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Download our iHus annexe brochure

Download our iHus annexe brochure

If you would like to download our annexe brochure, please complete the form below. You can also request for a hard copy to be posted to your home address. Have any further questions, why not request one of our team get in touch?

If you would like to download our annexe brochure, please complete the form below. You can also request for a hard copy to be posted to your home address. Have any further questions, why not request one of our team get in touch?


    Talk to an expert

    Whether you’re looking to build a garden annexe, or just have a quick question, get in touch with us today and one of our friendly team will get back to you.

      Download our iHus annexe brochure

      If you would like to download our annexe brochure please complete the form below. You can also request for a copy to be posted to your home address. Have any further questions, why not request one of our team get in touch?


        Get in touch with iHus

        If you want to speak to one of the team about how Multi-Generational Living can be achieved by building an annexe. Complete the form below.

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            If you would like to view an annexe show home, please complete the form below. Have any further questions, why not request one of our team get in touch?


              Download our Annexe Financial Guide

              If you would like to download our annexe finance guide please complete the form below. Have any further questions, why not request one of our team get in touch?

              Download our iHus annexe brochure

              If you would like to download our annexe brochure please complete the form below. You call also request for a copy to be posted to your home address. Have any further questions, why not request one of our team get in touch?

              Download Your Free Annexe Brochure