This simple guide from the FMB takes you through the pros and cons of each extension option so you can decide which is right for you.
Loft extension
Building upwards can be the perfect way to add precious extra space to your home. You can either look to convert an existing attic or add a whole new storey to your property.
Pros
- Loft extensions will add lots of value to your home. Housing market research has shown that the value of your house can increase by as much as 20% following a loft extension.
- Being higher up will give you better views from your new room.
- Loft extensions will be flooded with much more natural light than other extensions. Because of the height, positioning and angles of the windows, sky light windows let in much more light than other windows around your house so your new space will feel bright and airy.
Cons
- You may want to consider the ceiling height of the floor below. It could be an issue if your home has very low ceilings because they might have to be lowered still in order to go ahead with the extension.
- Loft extensions are often very warm and can overheat. It’s therefore important to invest in good ventilation.
- Due to structural strengthening works loft can be expensive for what you get in return when compared to an extension
Side extensions
The side return extension is a very common extension for those in terraced or semi-detached houses.
Pros
- Making clever use of the small unused side passage along your home can change a box kitchen into a larger and more sociable room with a kitchen and dining area.
- The smaller scale nature of the job means that side return extensions are more cost-effective. If you are pressed for time and don’t want building work to run on over a long period this could be a good option for you.
- Side return extensions run along the length of the existing room and this means you can make the room feel bright and airy by using skylights.
Cons
- If you are going to be building up to your neighbour’s boundary you will need to get a Party Wall Agreement.
- Removing an external wall will need significant structural work and although less work is required than some extensions, it is still a large building project.
Basement
A basement extension would add a whole new storey to your home and if you need a lot more space, it is a great alternative to moving to a larger property.
Pros
- If you already have a cellar, it might make economic sense to enlarge it and turn it into a habitable basement.
- If your design features windows into a well or courtyard, you can ensure you will have lots of natural light in your basement.
Cons
- A basement extension is the most difficult way to extend. It will be expensive and will be very disruptive for both you and your neighbours.
- You would need to employ specialists in excavation, structural engineering and waterproofing
Single Storey extension
Extending out into your garden will create a large, open plan living space.
Pros
- If you’re planning on living in your home while you extend it, this type of extension will involve the least disruption.
- You could minimise disruption even further by building a self-contained room.
Cons
- You are constricted by the size of your garden. As a general rule, your extension shouldn’t take up more than half of your outdoor space. If you have a small garden, this could limit how large you can build.
- The rooms in the middle of your home will become much darker if you chose to extend backwards.
Multi-height
A multi-height extension involves extending your home back into the garden with a second level on top. Most commonly, they provide a new kitchen diner with an extra bedroom or bathroom on top.
Pros
- Multi-height extensions create the most space in your home, giving twice the space of other types of extension.
Cons
- Planning permission can be difficult to get for multi-height extensions. This is because it will visibly affect the appearance of the house.
- A two story extension may adversely impact the light and privacy of your neighbours.