Home Extensions – Here’s What You Need to Know Before You Start

If you have never even thought about building a house extension before then you probably have a lot of questions. From the logistics to the legalities and even the budget, there’s certainly a lot for you to take on, so it pays to know where you stand before you move forward.

Meeting Building Regulations

It doesn’t matter whether your home extension can be built without needing planning permission because you still need to meet building regulations. The building regulations in your area will basically ensure that your building is structurally sound and that it is energy efficient too. It will also look into your ventilation, damp proofing and various other key aspects that will make your site safe. If you are adding a loft conversion, structural alteration, the removal of a load-bearing all or even the installation of a new heating appliance, then this will need to meet the appropriate regulations.

Will a Home Extension Add Value?

If you want your home extension to make any kind of economic sense, then you need to make sure that the value comes to more than the cost of the project. This can be difficult to assess, but if you want to help yourself here, then you can easily look up similar local properties to see how much they cost. It’s also important that you keep the ceiling price in mind too, and that you are able to adjust your plans accordingly.

How Big Should your Extension Be?

When planning a house extension, you may think that bigger is always better. This is not the case at all, and there are plenty of ways for you to create space without adding on more square feet. Clever design is crucial here because it might be that you can get the result you’re looking for with way less work. Of course, if you are aiming to match your house extension in with your existing property then it helps to source similar materials. This can be a tough job, but if you really put the work in then there’s no reason why you can’t make everything look perfect.

Choose the Right Designer

When it comes to your house extension, there are plenty of people who you can hire to help. These include architects, specialist designers and even architectural technicians too. If you want to help yourself here, then it’s a good idea to ask for recommendations from your family, friends and neighbours too. If you know that someone else has a project that is similar to what you are looking for, then don’t be afraid to ask them who did it. This is one of the best ways for you to get what you want, and it can make a huge difference to your build.

Extending Near a Sewer

If your home extension is going to be built over a sewer area, then there is a high chance that you need to contact the water board before you begin the work. The location of sewers are always carefully considered, so if you have a shared sewer that’s within 3m of your extension then you may need to get a document, known as a Build over Agreement. This usually comes from your local water authority. Work like this can be tricky and costly too, especially if the company need to put a new manhole in or even if they need to move any piping.

Extending above a Single Storey

It may seem appealing to extend over a garage, but structures like this are often unable to support the load. There are solutions that you can implement to try and help yourself here, such as underpinning a shallow foundation or even bypassing it with a steel frame that is bedded with new concrete pad footings.

Planning Services

Extending a kitchen may seem like an easy task, but it isn’t at all. You need to confirm the position of the cooker, white goods, units and more before your work even begins. This will help you to plan your ventilation, plumbing and even electrics too.  If you are planning on undertaking a lot of the work yourself then you can easily find building products at trade prices if you’re registered.

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Adding a house extension will put more pressure on your existing hot water system. You may even find that your current system is unable to cope too, and this is the last thing that you need. It’s advised that you work out how much heating your new extension will require so that you can factor-in your boiler output. This includes the reheat time, the size of the radiators and even the water cylinder too.

Access Restrictions

If you live in a terraced home that has somewhat restricted access, then this may limit some of the options that you have for your extension. For example, you might need to use your neighbour’s land for storage or you might have to conduct work during unsociable hours. In some instances, certain construction methods might not be available either, so it’s important that you keep this in mind too.

Living on Site

It’s 100% possible for you to live on-site when you are getting your home extended, but will you be able to live with the dust and mess? On top of this, you may end up slowing down the builder’s progress as they will have to work around your life. If you don’t feel as though you will be able to live with all of the disruption, then it may be worth looking into a short-term rental or even staying with some family or friends.

Connecting Old and New

Think about it, how well is the additional space going to sit alongside the original property? Sure, there are no hard and fast rules here, but you need to make the decision as to whether you want your new extension to compliment, or contrast with your main property.

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Conservation Areas

Each local authority have their own rules when it comes to conservation areas. Generally, the basis of this policy is to try and stop the area from losing character. In other words, if you are thinking about a house extension then it helps to contact your conservation officer. They can then help you to know if there is anything that you need to be aware of, or even if there is anything you need to take into account when planning your build.

Site Insurance

When you carry out any kind of extension, you need to make sure that you have site insurance. Sure, your builder may have some degree of insurance and this is great, but you do still need to make sure that you check their documentation too. It may be that the cover they have isn’t enough to make you feel comfortable during the build, or that they don’t cover fire, storm or flood damage.


Your glazing choice may ultimately have an impact on how your home is seen and how visible you are to passers-by. One solution would be for you to invest in some boundary treatments. Window treatments are also an option, as they can give you privacy without spoiling your view.

Contingency Budget

A healthy contingency budget will help you to cover any additional or even unexpected costs. When planning your budget, it is always a good idea to have a contingency cost of around 20%. That way, if something happens when your build is happening or if you need to hire some additional contractors to help you with the work you are doing then you can do this without you having to worry about a thing.

Protecting Trees

Some trees are protected. Sure, your extension may not require planning permission, but if you are near to protected tress then you won’t be able to alter or even prune them without getting prior permission. This can cause you real problems and you may even find that it impacts your build too. This is the last thing that you need, so take your time and make sure that you look into this properly before you go ahead and make your decision. It’s also a good idea to consult your local authority as they might be able to help you find out if there is anything that you can do to know this information in advance, so you can change or at least plan your build around it.

Of course, if you need to know anything else about your home extension then it is always a good idea for you to talk to a professional. When you do, they can then advise you on just about anything you need, and they can also assist you with planning out any aspect of your construction. When you do hire someone, it helps to do your due diligence and it’s also a good idea to look up reviews too. This will help you to make the best choice and it will also help you to hire someone who is experienced in the type of extension you are constructing.