Can I convert two flats into one house?

I own both flats in a semi-detached property – the one I live in has a residential mortgage while the other is rented out and has a buy-to-let mortgage. What do I need to consider if I wish to convert the flats into a single property?
Question: I own both the ground-floor flat and upper-floor flat of a semi-detached property, including owning the freehold. The flats were purpose-built and they share a common entrance. I live in the upper flat with a residential mortgage (£100,000 remaining), and I rent out the ground floor which is on a buy-to-let mortgage (£200,000). I would like to investigate turning them into one large single property. Is this possible? What costs and planning issues would I have to consider?
Answer: To convert the two flats into a single dwelling you will need Building Regulations consent and planning permission, and you may also need to serve a Party Wall Act notice as the flats are in a semi-detached property.
See if there are any restrictive covenants in the title that prevent the building being converted into a single dwelling.
You have two mortgages currently, so you would need to refinance to give you a single mortgage over the freehold.
I expect that there are two long leases at the moment on the ground floor and the first floor, and these leasehold interests would need to be extinguished.
Assuming that you still require about £300,000 of mortgage borrowing, the lender will need to be satisfied that the value of the converted property will be adequate security.
Do remember that the building may be worth less as one dwelling. You will incur surveyor’s/architect’s fees for drawing up appropriate plans. Notice to vacate should be served on the tenant and you may incur additional cost if the tenant has security of tenure.

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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 is legal director in the real estate group of Foot Anstey LLP in Exeter (
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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