Age and type of house

What should you ask about a purpose-built mansion block as against a house chopped into flats?

Ask which it is, because the risks differ. A purpose-built block was designed as flats, with common stairs and, often, a flat roof or a parapet. A converted house may have a stair cut through floors that were not a block, with thinner fire separation and a roof still built as a house. A home survey of one flat does not measure the fire performance of either.

Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.

What is the fuller explanation?

The lease and GOV.UK’s Right to Manage tests care about the building: purpose-built or not can matter in the small-conversion residence exception. The survey cares about what it can see: the flat, the stair it walked, the outside of the roof. It does not count the floor area for an RTM claim. Service charges exist in both kinds of building. The survey does not audit them.

Converted houses more often have odd sound paths and stacked bathrooms that were not in the original plan. Purpose-built blocks more often have long parapet gutters. Do not use one paragraph for both. A survey fee does not buy an upgraded stair. Ask the solicitor what the lease says you must contribute.

What should you ask your surveyor?

Are you treating this as purpose-built or as a conversion?
Which common parts did you walk, and which roofs did you not enter?
What are you leaving to the lease?

What are the typical next steps?

Tell your solicitor which sort of building the survey thinks it is, and ask them to check.
Do not assume fire doors were tested.
Read the roof comment against the kind of roof this building actually has.

Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.

Also asked about this

Does a lift mean it is purpose-built?

Often, not always. A lift is a machine. It is not a history of the walls. The survey has not serviced it.

Is a house of four flats a mansion block?

No. Use the plainer description. The RTM guide treats small conversions differently from purpose-built blocks.