Can I grant permission for a loft extension?

I own the freehold of a building, which is split into two flats. A prospective buyer of the first-floor flats wants to know if I will grant permission for him to have a loft extension. Is it simply a matter of saying yes?
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Question: I own a leasehold ground-floor flat plus the freehold of the whole building, which is split into two flats. The owners of the first-floor flat are trying to sell and the prospective buyer wants to know if I will grant permission for him to have a loft extension. Is it simply a matter of saying yes, provided planning permission and building regulations consent are granted? 

Answer: Who owns the roof space? Is it part of your freehold or part of the first-floor flat? Often the roof space is part of the freehold, in which case you must decide whether to grant a supplemental lease of it to the prospective buyer. The size of the first-floor flat would increase if you did so, and the property is likely to go up in value.

You would be entitled to charge a premium for granting a lease of the roof space, and to ask the buyer to pay your associated legal costs and any surveyor's fees. Seek advice from an estate agent or surveyor about how much you could charge.

If the roof space is not included in the freehold but is already included in the lease of the first-floor flat, your prior written consent, as freeholder, would still be needed to turn the space into a loft extension. 

The prospective buyer should provide you with the proposed plans and drawings, details of who would carry out the work, plus confirmation of planning and building regulations consent. The quality of any loft conversion is likely to impact on the value of your flat and your freehold but depending on the wording in the lease, you will not be able to withhold your consent unreasonably.

If you have a question for Fiona McNulty, please email or write to Legal Solutions, Homes & Property, London Evening Standard, 2 Derry Street, W8 5EE. 

We regret that questions cannot be answered individually but we will try to feature them here. Fiona McNulty is a partner in the residential property, farms and estates team at Withy King LLP (

These answers can only be a very brief commentary on the issues raised and should not be relied on as legal advice. No liability is accepted for such reliance. If you have similar issues, you should obtain advice from a solicitor.

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