A leafy cobbled residential street, of converted garages. SAM Conveyancing discussed the risks of buying a house with a garage conversion without building regulations, and how to resolve them.
Are you making an offer on a house with a garage conversion?
Our conveyancing solicitors are well experienced to handle your purchase, with or without building regulations.

All our fees are fixed and we can advise on retrospective regularisation vs building regs insurance.
Get a tailored conveyancing quote

Buying a House With a Garage Conversion Without Building Regulations

(Last Updated: 14/12/2023)
8 min read

Key Takeaways

  • Most garage conversions don't require planning permission but they do need to meet building regulations.
  • If the work is not up to building control standards, you will likely be unable to use the garage as a 'habitable' room.
  • As a buyer, your options to resolve this may be as simple as regularisation or indemnity insurance. Alternatively, you may have to reduce your offer or pull out altogether.
  • Older garage conversions may be safe from the planning officers.

Garage conversions are popular because they can add an extra room (and therefore usually increase the value of the house), for a relatively low cost. As long as the work is done properly - with planning permission, where required, and building control sign-off (this means they meet building regulations) - then this is a win-win for buyer and seller.

If you buy a house with a garage conversion without building regulations, the liability for the problem passes on to you as the new owner. The local authority could force you remedy the building regulations breach, meaning you'll end up paying for the seller's mistake.

How much does a garage conversion affect house value?

According to Virgin Money, a garage conversion can increase house value by 10-15%. Some conversions can be achieved for as little as £6,000, but this will increase to upwards of £10,000 if you want to add an en suite, depending on the size and quality of the build and materials.

The added value is in the extra bedroom, so this is why building regulations are so important. If you're buying a house with a garage conversion without building regulations, that room is legally unfit for habitation. You can continue to use the nicely converted extra room as you would a garage, but you can't live in it, or move a tenant into it.

Do I need to tell mortgage company about garage conversion?

You must tell your mortgage lender. Your solicitor will find out about the garage conversion and they will find out if it was never signed off by building control. It is their legal and professional obligation to inform the Lender as it may effect the value of the property. There is no point trying to hide this from the lender and it will likely cost you time and money when the purchase falls through if you do.

Your mortgage lender will have a surveyor value the property, to make sure that the money they are lending you to buy the property can be recovered by repossessing and selling it, if they absolutely have to. If the garage conversion does not meet building regulations, they will likely undervalue the property to a price more appropriate to a similar property, in a similar area, without the additional bedroom.

What happens if you haven't got building regs?

If the issue is simply that the building work was never signed off, but the seller (and your own surveyor) think the work is up to scratch, you have two options.


    Retrospective sign off

The safest is to ask the seller to apply for a letter of regularisation. This will require a building control inspector to visit the property. They cannot always give full approval, where the construction is hidden for example, but they can confirm that the council won't take action against you as long as what they can see meets regulations.

Unfortunately, where the works are hidden, this doesn't guarantee the work is structurally safe. In some cases, you may still require a structural engineer to carry out an intrusive survey to put your mind at rest before you allow anyone to sleep in the room. Furthermore, if the work does not meet the council's requirements, they will now be aware of the issue and may take action against the seller to redo the work to their standards. Even if this is a risk your seller is willing to make, waiting for a building control inspection can take a while, which may delay your transaction.


    Indemnity Insurance

Can I sell my house without building regulations certificate?

Another option is to get Building Regulations Indemnity Insurance. This is only suitable if the council is not yet aware of the works and it provides no guarantees as to the safety of the building work. However, it is a relatively affordable option which will allow you to push forward with the purchase (provided your lender will accept the policy) without too much delay. It will protect the lender's loan in the event that the unregulated work devalues the property. The buyer's conveyancing solicitor must broker this insurance and provide legal advice on the terms.


    Negotiate the price

If the garage conversion has been inspected and it does no meet regulations and/or you can't get insurance to cover it, you will have to negotiate with the seller. Either they will have to have the conversion remedied with proper sign-off this time, or they will have to bring their price down to meet the valuation by your lender, and/or reflect your costs for doing those works yourself after you complete. If you are lucky enough to be purchasing the property in cash (without a mortgage) then you could choose to go ahead with the purchase at the pre-agreed price, but you'd probably be getting a bad deal.

In this scenario, your seller could dig their heels in and refuse to lower the price, in which case they'd have put the property back on the market and hope that a cash buyer will pay what they're asking. This will put the seller back by weeks and there are still no guarantees they'll get the price they want without rectifying the garage conversion, so they should be willing to negotiate with you.

Make sure you instruct a conveyancing solicitor who can handle a tough negotiation if it comes down to it.

Fixed Fee | Rated Excellent on Trustpilot | No Sale No Fee

Buying a house with an unpermitted garage conversion

Only about 10% of garage conversions require planning permission - most fall under permitted development rights. Your solicitor will find out whether the title deed prohibited the garage conversion (some properties have restrictions on the title, which require that a garage remains as parking, especially in built up areas) and your planning report will reveal whether the planning permission for the garage conversion was sought (if not, you or your solicitor may need to enquire with the local planning authority to find out whether the garage conversion required permission).

If you're buying a house with an unpermitted garage conversion and it turns out planning permission was required after all, the local authority could force the seller (or you as the new owner) to restore the garage to its original condition, costing you money and potentially changing the value of the property. You will have to look into retrospective sign off or renegotiation. However, if the work is more than 10 years old, you may be in luck.

Do you need planning permission after 10 years?

The 10 year rule applies to any breach of use of land or buildings (excluding dwellings) which has not been challenged by enforcement action for the period of at least ten years. A garage conversion changes the use from a non dwelling (garage) to a dwelling (somewhere you will live). If 10 years have passed since the unpermitted garage conversion was completed, the seller may be able to apply for a certificate of lawfulness for the development, which would resolve the issue.

The 10-year rule also applies to a breach of any existing planning condition which has not been challenged by enforcement action for the period of at least ten years. There is also a 4 year rule which applies to extensions, but the Levelling-up and Regeneration Bill, aims to extend this to 10 years.

Frequently Asked Questions
Caragh Bailey, Digital Marketing Manager
Written by:

Caragh is an excellent writer in her own right as well as an accomplished copy editor for both fiction and non-fiction books, news articles and editorials. She has written extensively for SAM for a variety of conveyancing, survey and mortgage related articles.

Andrew Boast of Sam Conveyancing
Reviewed by:
Andrew started his career in 2000 working within conveyancing solicitor firms and grew hands on knowledge of a wide variety of conveyancing challenges and solutions. After helping in excess of 50,000 clients in his career, he uses all this experience within his article writing for SAM, mainstream media and his self published book How to Buy a House Without Killing Anyone.

People also searched for

SAM Conveyancing explains if you should get building regulations indemnity insurance

Should you get building regulations indemnity insurance

SAM Conveyancing's Guide to Buying a House Without Building Regulations Approval

Buying a House Without Building Regulations Approval

Tips on Buying a House with Loft Conversion Without Building Regulations from SAM Conveyancing

Buying a House with Loft Conversion Without Building Regulations