BuildWise guides
Home renovation guides for UK homeowners
Straight answers on the decisions that shape an extension, renovation or conversion — from planning permission and budgets to appointing professionals and signing off the work.
Budget & costs
Extension cost calculator: how to work out your build cost per square metre
There is no single cost per square metre for an extension, but there is a reliable way to calculate your own number. This guide gives you the method, the current UK ranges and the…
How much does a house extension cost, and how do you set a realistic budget?
Most UK homeowners start with a number in their head and no idea whether it is realistic. This guide gives you the cost ranges the industry actually works to, then shows you how t…
Completion & defects
Construction
How long does a house extension or renovation take, start to finish?
People ask how long the building work takes. The build is usually the shorter half. From first idea to finished room, most extension projects in the UK run 9-18 months, and the pa…
What to expect while living through building work
Most homeowners stay put through an extension. It is possible, and it saves rent, but it works far better when the ground rules were agreed before the first delivery arrived. DECI…
Contractor selection
How to compare builders' quotes beyond the headline price
Three quotes for the same extension can differ by £30,000, and the cheapest is often the most expensive by completion. The gap is rarely profit. It is scope, assumptions and provi…
How to get quotes for a small job, and compare them fairly
A small job — a new basin, a few doors hung, one room repainted — does not need a full tender. It does need the same clarity you would give a big project, in a fraction of the wor…
Finding professionals
General advice
Party wall
How to serve a party wall notice, and what it costs
If your work is notifiable under the Party Wall etc. Act 1996, you must tell your neighbours in writing before you start. This is the procedural guide: what to serve, when, what h…
When do you need a party wall agreement, and how do you get one?
If you are digging foundations near a neighbour's property, cutting into a shared wall, or building right up to the boundary, the Party Wall etc. Act 1996 probably applies. It is…
Planning
Do I need planning permission for my extension or renovation?
Plenty of home projects in England and Wales are built without a planning application, under permitted development rights. Plenty of others are refused because the owner assumed t…
Do you need planning permission for a garden room or outbuilding?
Garden rooms, garden offices and studios are usually built under permitted development as "incidental" outbuildings. The rules are generous, and the two mistakes that cost people…
Do you need planning permission for a loft conversion?
Most loft conversions in England and Wales are built under permitted development rather than a planning application. But "most" is not "all", and the two things people forget — bu…
Products & finishes
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