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Buying property with 'illegal' extensions

30 replies

Pegs11 · 27/01/2026 11:56

Hi, my partner and I are buying a property - a stone cottage, built around 1910 I believe. The current owner has been there 50 years and the property has been lovingly improved over the decades and is on the whole very well maintained... BUT we have encountered a couple of hiccups and I have two questions for you lot to see what you think! Trying to get a consensus here...

First part of question:

We are mid-way through the process and it turns out the vendors have no paperwork for the three extensions (and a knock-through) they did in the 1980s/1990s.

We had a level 3 survey done and the surveyor said that while the extensions would certainly not conform to modern building regs due to their age, he could see no signs of them being structurally unsound, and as they've been standing for so long, it's unlikely that they would be unsafe. But that without getting a structural engineer in, it's impossible to know for sure.

I don't think we can get a structural engineer in at this stage - the vendor would need to agree to invasive work being done and I can't see them doing that. The extensions were done too long ago for us to be able to get retrospective planning/building regs (ie, regularisation).

Our concern is around the potential for issues when reselling the property in the future. We don't plan to stay there forever and would hate to be in a situation where we struggle to sell it because of the illegal work that has been done to it and the lack of safety certificates. If WE are having doubts, how likely is it that future potential buyers will also have doubts...? I don't know if we are especially cautious buyers... perhaps most people would be more chilled out about it or perhaps wouldn't consider it an issue at all?

Second part of question:

The house has had some other questionable work done over the years. In the garden, they built a brick workshop with cement floor over a public sewer, without permission. They also put a brick porch out front, which is in breach of either planning rules or a restrictive covenant (or both), and they created a driveway with hardstanding without permission and without a dropped kerb, and the surveyor said there could be public pipes etc running under it and that the council might take issue with that (although they haven't so far).

We can get indemnities for all of these things, but would that be satisfactory for most people? And again, we are concerned about selling the property in the future with these issues in place.

Please let me know your thoughts on both of these questions. Would you buy this house?!

OP posts:
PlatinumMoon · 27/01/2026 11:57

no

SalmonOnFinnCrisp · 27/01/2026 11:59

Based on your circs ...It's a no from me.

I specifically buy properties that arent tricky/weird because I want assets i can move in any market

You dont want to stay here forever.
Uk market isnt buoyant.
It's not "the dream".
Find something else.

Gudinne · 27/01/2026 12:01

From what you have outlined I think I would be okay with indemnity insurance. What does your lender say?

canidigityes · 27/01/2026 12:05

Depends really - if it was my dream home or nothing likely to come up in that area for my budget and I was going to stay for several years then no wouldn’t bother me

Just because it wouldn’t comply with modern building regs doesn’t mean it’s unsafe/unsound - TBH modern construction methods are hardly the pinnacle of building quality (go look around any new build estate given how many inspections/signs off they go through)

patrick89423 · 27/01/2026 12:07

Does the price reflect the fact that there are all these irregularities? They could well cause problems when you come to sell!

SlipperyLizard · 27/01/2026 12:07

I wouldn’t, but my risk tolerance for this kind of thing is low. Might be different if you were planning to stay there a long time.

Mildura · 27/01/2026 12:10

Gudinne · 27/01/2026 12:01

From what you have outlined I think I would be okay with indemnity insurance. What does your lender say?

I am pretty cynical when it comes to indemnity insurance.

Given the age of the works I would be of the opinion that the risk being insured is practically non-existent.

At some point during the life of a property it has to be accepted that not everything is going to have a certificate or some other bit of paper that's relates to each extension/alteration.

Tortephant · 27/01/2026 12:14

I wouldn’t be concerned by part 1. Part 2 is more concerning.
indemnities aren’t normally worth the paper they are written on. I’d either walk away or negotiate a chunk of the agreed price.

housethatbuiltme · 27/01/2026 12:15

Historic extensions don't need building reg certificates and planning permission, many where built before it was even really a thing.

My house has 3 extensions, no paperwork for any of them and no it was not raised as a concern at all by the solicitors. No idea when they where built but they pre-date 1990.

Surveys cover their ass (thats all they exist for) our told us to get a structural engineer in to confirm the building work had RSJs. We didn't need to because common sense said it had to or wouldn't be standing and during the renovation we found the RSJ exactly as common sense said they should have been. Our surveyor also swore down a chimney breast was removed and we needed the paper work from it and to have it check by a structural engineer. We pointed out that we firmly believed it was just boxed in but he insisted from his 'expert' opinion that wasn't true. We ignored him and as part of the reno removed the (frankly very clearly) false stud wall and voila their stood the 'removed' chimney breast fully intact.

House we where buying previously had extension with no permission too and they said there no point worry. You only really should consider it possibly being an issue if the works where done this millennium. Over 25 years old and nothing will happen.

No historic build will confirm to modern regulations and the don't have to, they only had to confirm to any rules of the time they where built.

BarnacleBeasley · 27/01/2026 12:22

I have a house with a dodgy extension, and when I bought it the vendor supplied a surveyor's report confirming that it was definitely more than 30 years old, which was fine.

billysboy · 27/01/2026 12:25

speak to a planning consultant , a certificate of regularisation should be fine , if they have been there for more than 10 years they will require a certificate of lawfulness

housethatbuiltme · 27/01/2026 12:25

As for the second part of the question, they maybe more valid issues.

Things like the drive way. Is the house sold with a 'driveway' as a feature? if so you can ask for a reduction in price due to it not actually having legal driveway access which essentially just makes it a patioed front yard.

When was the porch built and which does it fall foul of? Houses round here have covenants from long dead reverends of local churches. I'm not sure who would take action if they caught us 'drinking intoxicating liquors' or how they even would. Of course we and many of our neighbors drink in our homes, a newer build shop on the other side of the road even sells the devil sin liquid lol. Apparently its just a very common old covenant for land that was owned by churches. I'm also not allowed to slaughter animals or sell sex.

I'm not experienced with public sewer issues, I suggest you look into it and speak to your solicitor for advice. You do pay them to explain it to you, ask what the risk of issues is and your options.

OnARainyDay2012 · 27/01/2026 12:26

I've had similar issues with older properties. I would be asking for indemnities (at the sellers cost) and permission for structural works (at your cost. Without those no I wouldn't go ahead.

CloudPop · 27/01/2026 12:28

SlipperyLizard · 27/01/2026 12:07

I wouldn’t, but my risk tolerance for this kind of thing is low. Might be different if you were planning to stay there a long time.

Same. And I certainly wouldn’t be comfortable being reliant on an insurance policy.

Rubinia · 27/01/2026 12:30

housethatbuiltme · 27/01/2026 12:25

As for the second part of the question, they maybe more valid issues.

Things like the drive way. Is the house sold with a 'driveway' as a feature? if so you can ask for a reduction in price due to it not actually having legal driveway access which essentially just makes it a patioed front yard.

When was the porch built and which does it fall foul of? Houses round here have covenants from long dead reverends of local churches. I'm not sure who would take action if they caught us 'drinking intoxicating liquors' or how they even would. Of course we and many of our neighbors drink in our homes, a newer build shop on the other side of the road even sells the devil sin liquid lol. Apparently its just a very common old covenant for land that was owned by churches. I'm also not allowed to slaughter animals or sell sex.

I'm not experienced with public sewer issues, I suggest you look into it and speak to your solicitor for advice. You do pay them to explain it to you, ask what the risk of issues is and your options.

this

Ophy83 · 27/01/2026 13:08

Is there really a sewer there? We sold a house recently and our buyer's surveyor said there was a sewer under our kitchen extension. No one mentioned it when we got planning permission nor when the foundations were being dug, nor has any utility company ever required access so it was a bit of a puzzle. We got an indemnity I think for about £100, it may have been less.

Bitzee · 27/01/2026 13:19

The only part that would really cause me concern is the driveway without a proper dropped curb as there’s nothing preventing people parking across it therefore it’s not really a driveway so much as a paved front garden. Decades old extensions are never going to have up to date building regs and don’t usually need planning permission- it’s something you’ll likely encounter with any older property. Restrictive covenants are often outdated and unenforceable too. And I probably wouldn’t be concerned with an outbuilding over a sewer but perhaps ask your solicitor about that one.

Somersetbaker · 27/01/2026 13:42

Ophy83 · 27/01/2026 13:08

Is there really a sewer there? We sold a house recently and our buyer's surveyor said there was a sewer under our kitchen extension. No one mentioned it when we got planning permission nor when the foundations were being dug, nor has any utility company ever required access so it was a bit of a puzzle. We got an indemnity I think for about £100, it may have been less.

I had similar, the buyers solicitor found a plan that seemed to show a surface water drain, running diagonally across my back garden under the extension, then connecting to the surface water drains in the development behind. I had to point out that this was fiction, as it would have meant the drain running under a mature oak tree that predated my house and that the development behind was a field when I moved in. Finally solved by somebody reading the legend "proposed drainage scheme", then finding the correct drawings.

DrySherry · 27/01/2026 16:09

For me it would come down to price. If the property was suitably discounted to take in to account the issues you have highlighted I may still consider it. My idea of how much it should be discounted would likley be more than the vendors though. Particularly as house prices seem to be heading for a rough period of falls.

metalbottle · 27/01/2026 16:10

Unless you are getting it at about half market value, walk away.

Deliberations · 27/01/2026 16:17

The only thing that might concern me would be building over the public sewer. You could get a drainage survey done - they might also be able to confirm if there are drains under the hardstanding at the front.

I had an issue buying my current house as the conservatory was built over the sewer - but it turned out that was an old no longer used pipe - so no issue in the end.

All the other issues would be quite common in millions of houses that age.

housethatbuiltme · 27/01/2026 17:03

metalbottle · 27/01/2026 16:10

Unless you are getting it at about half market value, walk away.

Well thats an insane thing to say.

The drop curb warrants a reduction of a few thousand maybe, thats it.

Pegs11 · 27/01/2026 18:13

Thank you for all the responses so far, this is incredibly helpful 😊

OP posts:
StripedVase · 27/01/2026 18:29

If you need a mortgage on it the lender may not lend because of this; the same would go for any future buyers from you were you to try and sell. So that makes it risky even if you believe the work itself is liable with.

MissSookieStackhouse · 28/01/2026 00:33

Too many red flags! The illegal extensions may actually devalue the property and it may be worth less than your accepted offer. I was house hunting last year and saw a 3 bed house I liked the look of on Right Move, but it went under offer before I had a chance to view it. A couple of months later it came back on at a much lower price. It was also now being re-marketed as a 2 bed. There was a new note in the blurb which said it had an unofficial loft conversation in the 80s which didn’t comply with current regs. Therefore it couid only be sold as a 2 bed with a loft room, not a 3 bed house, hence the lower price.