The size of an extension that can be built without planning permission varies depending on the location of the property and the type of extension being built. However, in most circumstances, you can build a single-story rear extension that does not exceed 50% of the total area of land around the "original house". There are also dimension and material restrictions to consider.

For example, single-story rear extensions cannot exceed 4 metres in height and must not extend beyond 3 metres from the original house for terraced or semi-detached houses, and 4 metres for detached houses. A different route that might be considered is going through a ‘prior approval’ application for a larger home extension. This works slightly differently but is generally less risky than a full planning application if the proposals have limited impact on your neighbours. The maximum depth for a single-story rear extension is 6 metres for terraced or semi-detached houses, and 8 metres for detached houses, unless your property has had its permitted development rights removed. In all cases, the exterior materials you use must match the look of the rest of the house. There may be some flexibility as most local authorities understand that exact products (roof tiles, bricks etc) are sometimes discontinued but you will be required to match materials as best as you possibly can.

We always advise our clients to seek a Certificate of Lawful Development which affirms that your proposals qualify as permitted development. This is a simple and cheap application that shouldn’t be refused (so long as it meets all conditions) and ensures peace of mind for you and any potential mortgage lenders, solicitors or buyers when needing to prove the extension is legitimate. It's important to note that the regulations can vary depending on the local authority’s area designations or where there are previous planning conditions on the property that might restrict or remove your permitted development rights. The most frequent reasons we see for permitted development rights being removed is if your property is in a conservation area, if it’s a part of a particularly new-build estate or if it’s already been substantially added to already. Always get in touch with us or seek alternative professional advice before paying for design work or applications to understand your circumstances fully.

If the front faces a road, then no, you cannot carry out a meaningful front extension under permitted development rules. In cases where your house sits on a corner plot where the side wall faces the road, this cannot be extended under permitted development either. You’d instead have to apply for full planning permission which may not necessarily be a bad thing. Because of the fairly restrictive rules around permitted development, creativity and sometimes functionality of your spaces can become stifled. Even if you can get something built using permitted development, it’s always worth inquiring about the pros and cons of instead submitting a full application which may be able to get you a much better extension.

However, you are typically able to construct a front porch on your home under permitted development. This can face a road, so long as the external ground floor footprint is no larger than three square metres, no part of the porch would be taller than three metres above ground level, and no part would be within two metres of any boundary or the highway. This enables the construction of small internal porches, open canopies and the extension or alteration of existing porches.

Not exactly. If you require planning permission, the local authority will normally consult your neighbours as part of the process which can become important if you submit a larger home extension as mentioned above. If your neighbours object, the authority will determine the impact of your proposals within planning policy terms and decide if it is acceptable or not. This does not remove the need for other duties which involve letting your neighbours know about the proposals (such as signing Party Wall Agreements). We always recommend being completely transparent and upfront with your neighbours at the earliest stage possible. We can help a lot with this, visiting and talking through the proposals with them alongside any drawings or visualisations that might help them understand your intentions.

In addition to providing more living space, a modern house extension can offer several other benefits to homeowners. By bettering your thermal envelope with fully-insulated walls and improving air tightness, our extension builds can help reduce energy bills. During cooler months, the thermal capabilities of our extensions allow them to absorb sunlight while keeping the draughts out, which results in a more comfortable living space.

We also ensure high-quality windows and doors are included in our extension designs which provide additional energy efficiency benefits due to their advanced manufacturing. By reducing your carbon footprint and enhancing the appearance of your home, our modern house extensions are an excellent investment for any homeowner.