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5 steps to build a beautiful side garage extension

These are the five essential steps you'll need to undergo in order to bring your dream garage extension to life through the side of your home.

8 min read

If you’re looking to take your garage to the next level, then a side extension might be just the ticket. For certain properties, a side extension can help square off your property and make a more intuitive floorplan. For others, this project can be tied in with a conversion, letting you renovate your garage into a more habitable (and valuable) space.

So, what to do if you’ve got the side of your garage going spare? As the UK’s leading home extension platform, we’re experts in growing new spaces! Here are all the stages required for building a beautiful new side garage extension.

Why is a side garage extension right for you?

There are plenty of reasons for considering a side extension for your garage. Some of the most common reasons our consultation team encounters are…

You can turn a one-car garage into a two-car garage

It goes without saying, but an extended garage means you can take a one-car space into two. This is a great option if you’ve been struggling to accommodate all your vehicles in the existing space, or if you live in an area where parking is at a premium. Should car parking spaces be in short supply on your street, then having a bigger garage could lead to a significant boost to the value of your property.

Get extra room for a utility room or workshop

A garage conversion doesn’t have to mean you extend your actual garage. It can be used to open up the neighbouring property, providing a much needed extra room on the ground floor. Even small side extensions can have a big impact. For instance, you won’t need a lot of extra space to accommodate a new utility room, likewise a new workshop or home office.

Build a new room

If your garage has been going spare, you might want to consider converting it into a new room entirely. Whether this is a ground-floor bedroom, bathroom, home gym or even a new cinema room, you’ll find there are plenty of options available - especially when you have the right designer by your side.

How to build your side extension

As a homeowner, your role is going to be less about getting down in the dirt, and more about getting your paperwork in order. This might not be very glamorous but it is vital and will pave the way to getting you on the construction site.

To bring your garage extension to life, here are the key stages you’ll need to consider.

Step 1: Measured survey

If you don’t already have accurate existing drawings of your property, a measured survey will need to be carried out. Most surveyors will stick to the traditional route and opt for hand survey. However, services like Resi are now offering commercial grade laser surveys, which can be completed much faster and with a greater degree of accuracy.

Learn more: What kind of survey do I need for my house extension?

Using the information gathered from your measured survey, your surveyor or designer will map out your home as it stands today. These initial architectural drawings are what’s known as ‘existing drawings’ and form the basis for the design work.

Your designer will assess your existing drawings and pinpoint any issues your project might face. Common considerations tend to be…

  • How much room do you have to play with
  • The potential impact on neighbouring properties
  • Anticipating any privacy issues
  • Consideration of the street scene and any nearby roads
  • How much natural light does the property receives

Should any of the above raise concerns, don’t worry. Your designer will present their solutions to you during your initial conversations.

Step 2: Proposed design

Once the existing drawings of your garage are in hand, it’ll be time to discuss your extension with an architect or experienced designer.
During this stage, you and your designer will set out what you want your garage extension to look like. This includes…

  • Envisioning your future layout
  • Exteriors
  • The amount of glazing you wish to include

These designs are most concerned with the aesthetics of your household, and are used within the planning stage to get approval from your local authority, should this be required.

You’ll make a lot of key decisions while these drawings are prepared, such as setting out your ideal budget, and assessing what is required under planning and the building regulations for a garage extension.

It’s worth noting that because they lack structural details and other technical aspects, your architectural drawings shouldn’t be used for construction purposes. To save on costs, it’s better to wait for planning approval before you invest in more technical calculations.

House extension: plans and drawings

An example of architectural drawings produced in the design stage.

Step 3: Planning

With the drawings prepared during the proposed design, you’ll need to decide which application you need to make: full planning permission or a lawful development certificate.

A lawful development certificate is recommended if your project comes under your permitted development rights. It’s proof to both your local authority and future buyers that your garage extension was legal at the point of construction. Learn more about permitted development rights.

If your project doesn’t come under permitted development rights, you are legally required to obtain planning permission, whereby your local authority will assess your proposed design to see if it can be given the green light.

In both scenarios, your designer can help put together a planning package that includes: your existing drawings, proposed designs, plus the verifying information required by your planning authority. Applications typically take 8-10 weeks to reach a decision.

Step 4: Building regulations

Building regulations are a set of statutory requirements that all buildings must meet in order to create a safe and healthy environment to inhabit. They cover everything from the structure, thermal performance, sound-proofing, drainage, all the way to fire safety - to name just a few!

At Resi, we believe the best way to meet these conditions is to prepare a building regulations package.

The benefits of this package are…

  • Your technicians will provide a detailed set of drawings, ensuring your future space meets all the legal requirements. This protects you both in the eyes of the law and ensures you spot any issues before construction takes place.
  • The level of detail in this package means contractors can provide a better quote during the tendering stage, as well as having a comprehensive plan to work from during construction.

While the drawings prepared during the planning stage were concerned with the future look of your property, the technical drawings produced in this package will go much further in laying out key information. Using the input of specialists, such as structural engineers and surveyors, your team will make sure every little detail of your garage extension is properly mapped out so you can start construction with confidence.

Remember: even if you opt against a building regulations package, you will still need to hire a structural engineer to produce the key calculations needed to keep your extension standing.

Step 5: Find the builders

The benefit of investing in a building regulations package for your garage extension is that it will make life much easier during the tendering process, as potential contractors will have a much better understanding of what your side extension will involve.

We always recommend talking to at least three contractors and getting references from each.

These builders will first offer an initial estimate before they propose a site visit. This estimate is an early indication of a building contractor’s thoughts on the labour and material cost of your project.

To provide this initial estimate, the contractor will make some assumptions about your project. These will include:

  • The state of the existing building
  • The level of finish required
  • Additional works that may/may not be included in the scope

These estimates do not include VAT and large ticket items such as glazing, kitchens, finished flooring, bespoke joinery and sanitaryware.

The benefit of these assumptions is they give you an understanding of where a contractor positions themselves in the market so you can make comparisons at an early stage and select who you’d like to arrange a site visit with.

After viewing your property and learning more about your project, your selected contractors will then be able to provide a full tender for your build, which will include a more detailed breakdown of costs. Then all you’ll need to do is select the builder who you think will be best for the job.

Garage extension new bathroom

An example of a bathroom which could be created through a side garage extension.

Do I need planning permission for side garage extensions?

Side extensions are an attractive option for homeowners because they don’t always need a full planning application - even for garages.

Permitted development rights allow you to extend your garage outside of planning permission, as long as your designs, property, and site fit the guidelines.

Design guidelines

  • Sits to the side (as long as this will not face a highway) of the house (not the front)
  • Uses similar building materials to the existing house
  • Takes up less than 50% of the size of the land around the original house ("original" being the latest of when the property was built or if it was built before 1948, then as it stood on 1st July 1948)
  • Takes up less than 50% of the width of the original house
  • Is less than 4m in height (or less than 3m if within 2m of a property boundary)
  • Has eaves and a ridge that are no taller than the existing house

Properties excluded from permitted development rights

  • Listed buildings
  • Flats or maisonettes
  • Some new developments

It’s worth noting that homes in conservation areas can find their permitted development rights limited, or even suspended, so it’s worth checking with a planning expert about what might be possible.

Looking to extend your garage? Whether with a side extension, rear, or even above, our team can help you understand the potential in your garage with a free consultation. Book yours here or get an understanding of the initial costs with our quick quote tool.

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