What a single storey extension involves
A single storey extension extends the ground floor of a house, most often at the rear. The work runs from foundations and drainage through the brick or block shell, roof, windows and doors, to the internal plastering, electrics and finishes. Each stage must be right before the next covers it, which is why sequencing and inspection matter throughout the build.
Rear and kitchen extensions
The most common brief is a rear extension that opens the kitchen into the garden. Removing or altering the rear wall introduces structural work, usually a steel beam designed for the load, and the junction between old and new needs careful detailing to keep the building weather-tight and warm. These are engineering and building-regulation matters, resolved with the appropriate professionals rather than guessed on site.
Planning permission and permitted development
Many single storey rear extensions fall within permitted development rights, subject to limits on depth, height and position, and to the property's history and location. Some homes have those rights removed or sit in protected areas. Always confirm with your local council before committing to a design, because building first and checking later is an expensive mistake.
Building regulations
Separate from planning, building regulations cover the structure, insulation, drainage, electrics and fire safety of the extension. The work is inspected at key stages and certified at the end. Treat the inspections as part of the programme rather than an obstacle, and keep the completion certificate safely with your house documents.
How the work is sequenced
A typical sequence is setting out, excavation, foundations, drainage, the rising walls, roof structure and covering, then windows, doors and the internal first and second fix. Daniel's NVQ carpentry qualifications support the timber stages, and the wider extensions and renovations page explains how building work sits within the business.
Living in the house during the build
Most families stay in the house during a single storey extension. There will be noise, dust and a period where the rear of the house is opened up, so the build is planned to keep the home secure and weathertight at each stage. Agree working hours, access and where materials will sit before the work starts.
Cost factors to understand
Size, ground conditions, structural work, specification and finishes all change the cost of an extension. The house extension cost guide explains those factors so you can compare quotes on a like-for-like basis. A site visit and a clear brief are the only reliable route to a figure for your project.
Frequently asked questions
Do I need planning permission for a single storey extension?
Many fall within permitted development, but limits on size, height and position apply and some properties have restrictions. Confirm with your local council before committing.
Do building regulations apply to a small extension?
Yes. Structure, insulation, drainage, electrics and fire safety are all covered, with inspections at key stages and a completion certificate at the end.
Can we stay in the house during the build?
Usually, yes. The work is sequenced to keep the house secure and weathertight, though expect noise and dust while the rear wall is opened up.
What affects the cost of a single storey extension?
Size, ground conditions, structural alterations, specification and finishes are the main factors. The cost guide explains them in more detail.