Warranty for converting a house into an HMO
Turning a family house into ensuite rooms or bedsits? Structural cover for the building, optional cover for the ensuites, kitchens and fit-out - arranged before you start on site.
- Instant response
- Insurer quotes usually within one working day of your proposal
- UK FCA Regulated Broker
- Structural and non-structural cover
- We fill in the proposal form with you
The short answer
A house to HMO conversion can usually be covered by a structural warranty for the building, and by non-structural cover for the ensuites, kitchens and fit-out from providers that offer it. The provider looks at the existing house, the structural changes and the services running through it, and the HMO is usually certificated as one property.
The best time to arrange it is before work starts on site.
Typical works
What a provider wants to see on an HMO conversion
Every conversion is different, but these are the works that come up most often when a family house becomes an HMO, and what a warranty provider usually wants to see for each.
| Typical work | What the provider usually wants to see |
|---|---|
| New partitions to make extra rooms | Existing and proposed floor plans showing the new room layout |
| Load bearing walls taken out and steel beams put in | A structural engineer's drawings and calculations, and how the loads now reach the ground |
| A loft room or dormer for extra bedrooms | Drawings and calculations for the new floor and roof structure |
| A rear or side extension | Foundation design, and sometimes ground conditions, for the new part |
| Ensuites in every room | The drainage and ventilation routes, especially where soil pipes and ducts pass through floors and walls |
| Fire separation and escape routes | The fire strategy agreed with building control, as it affects floors, doors and walls |
| The existing house | Its age and construction, and on many projects a condition survey |
What providers check
Why HMO conversions get a closer look
An HMO conversion asks a lot of an ordinary house. Several people living independently under one roof means more bathrooms, more cooking, more water and more wear than the house was built for, and the changes are often bigger than they look from the street.
- Structural changes - walls removed, beams added, rooms added in the roof - put the old structure to work in new ways.
- Services through the structure - soil pipes, waste runs and extract ducts cut through joists and walls for every ensuite.
- Water - more showers mean more chances of a leak, so waterproofing and drainage matter.
- Fire separation - new fire doors, ceilings and stopping affect the floors and walls.
None of that rules a project out. It means the provider wants to see the drawings and the engineer's work, and its surveyor will look at those areas when inspecting.
The existing house
How the existing house is assessed
The provider's surveyor inspects the new work as it goes in, but nobody from the provider saw the original house being built. So the provider looks at the existing structure separately - its age, how it is built and its condition. On many projects it asks for a condition survey by a surveyor or engineer.
A survey that finds problems does not usually rule out cover. The provider may ask for repairs or strengthening before it includes an element, ask for more investigation, or exclude part of the old structure from the cover. We set out what it proposes before you commit.
One certificate for the building
An HMO kept and let as one property is usually covered as one property, with one certificate for the building rather than one for each room. If the house is being split into self-contained flats for sale instead, each flat is normally certificated on its own - our sister brand Conversion Warranties handles flat splits and the existing structure of conversions in more depth.
Register before you start
A warranty is simplest to arrange when the project is registered before work begins on site. The provider can see the existing house before it is opened up, its surveyor can inspect the new work at the key stages, and more providers will consider the project. A conversion already under way can sometimes still be covered, but the provider needs more evidence of the work done and the price is usually higher - see finished HMOs and refinancing.
Adding cover for the ensuites and fit-out
A structural warranty covers the building, not the ensuites, kitchens and fit-out that make up most of the spend on an HMO conversion. Some providers offer non-structural cover for that work as well. See non-structural HMO cover.
Documents to have ready
- Existing and proposed floor plans, and elevations or photos of the front and back
- Structural engineer's drawings and calculations for beams, lofts and extensions
- A condition survey of the existing house, if you have one
- The number of lettable rooms, the cost of the works and the rebuild cost of the finished property
- Who is doing the work, their experience, and your building control route
Planning permission and HMO licensing are separate from the warranty - they are for your planning consultant and the local council. We do not give planning or licensing advice.
HMO conversion warranty questions
What does a warranty provider look at on an HMO conversion?
The existing house, the structural changes such as removed walls, steel beams, loft rooms and extensions, the drainage and ventilation for the ensuites, fire separation, and who is doing the work.
Is the existing house covered as well as the new work?
Usually to some extent, but it depends on the provider and on its assessment of the old structure. Some elements may be excluded or need work to bring them up to standard first.
Is an HMO covered as one property or room by room?
An HMO kept and let as one property is usually covered as one property, with one certificate for the building.
Can I get cover if I add a loft room and an extension for extra bedrooms?
Usually, yes, as part of the conversion. The provider will want the structural drawings and calculations for the new floor, roof and foundations, and will inspect those stages.
Last reviewed 30 October 2026 by the HMO Warranties team. General information only - not advice. Your cover is set by the policy wording.
Get a quote for your HMO conversion
Tell us about the house, the number of rooms and the work. We will come back with the providers likely to cover it and what they will want to see.
- Takes under a minute
- Instant reply by email with your reference
- Insurer quotes usually within one working day of your completed proposal
- HMOs anywhere in England, Scotland, Wales and Northern Ireland
- Free and no obligation
Already filled in a proposal form? Email it to us or send it on WhatsApp with any drawings you have and we will take it from there.
