Somerset has more eligible agricultural buildings than almost any other county in England. Class Q permitted development rights — introduced in 2014 and significantly expanded in 2024 — allow the conversion of many agricultural buildings to residential use without going through full planning permission. But the rules are complex, Somerset councils apply them differently, and getting it wrong is expensive. Here is everything you need to know in 2026.
What Is Class Q Permitted Development?
Class Q (now technically Part 3, Class Q of the GDPO) allows the change of use of agricultural buildings to residential dwellings (Use Class C3) without requiring a full planning application — subject to prior approval from the local planning authority. Following the 2024 amendments, the limit increased to 10 dwellings or 1,000m² of floor space per holding, making it viable for larger agricultural complexes.
Does My Somerset Barn Qualify for Class Q?
Your barn may qualify if it meets all of the following criteria:
- The building has been in use (or last used) for agriculture for at least 10 years
- The building is structurally capable of conversion without the need to effectively rebuild it
- The holding it sits on is not a new holding created to exploit Class Q rights
- The building is not in a National Park, AONB, or a Site of Special Scientific Interest (though rules differ)
- The proposed floor area does not exceed 1,000m² or 10 dwellings per holding
- The building is not a listed building (listed buildings require listed building consent regardless)
Note:Key Somerset-specific point: Somerset Council and Dorset Council LPA officers take a strict view on the "structural conversion" test. If your barn requires any degree of rebuilding rather than pure conversion, prior approval will typically be refused. You need a structural engineer report confirming the building can be converted in its existing state before submitting.
Class Q Barn Conversion Costs in Somerset 2026
| Item | Typical Cost |
|---|---|
| Prior approval application fee | £120 per dwelling |
| Structural engineer report | £800 – £2,500 |
| Planning consultant (recommended) | £1,500 – £4,000 |
| Conversion works — basic specification | £80,000 – £130,000 per dwelling |
| Conversion works — high specification | £130,000 – £220,000 per dwelling |
| Drainage and services connection | £8,000 – £25,000 |
What Works Are Permitted Under Class Q?
Under Class Q, you are permitted to carry out building operations reasonably necessary to convert the building — including new windows, doors, rooflight installation, insulation, internal walls and mezzanine floors. You cannot extend the external footprint. External materials must be those commonly used in the area.
Why Use Brick Builds for Your Class Q Conversion?
We have completed multiple Class Q barn conversions across Somerset and Dorset and understand the prior approval process in detail. We work with trusted planning consultants and structural engineers who know Somerset LPA requirements, and we carry out the full conversion — from groundworks and structural alterations through to internal finishes — on a fixed-price contract.
Talk to Brick Builds about your Somerset barn conversion — free initial consultation
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