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Anyone knock down a load bearing wall without a structural engineer?

(26 Posts)
KatTwam Thu 17-Sep-15 11:13:28

Hi all,

We are intending to knock down a wall between our kitchen and conservatory (no comments necessary on this, I know it will be cold!). We have spoken to around 5 builders and all bar one say they can do the calculations themselves for the steel beam that is needed. The one that says that we should get a structural engineer to do the calculations has made me doubt all the others.

I have found conflicting advice on the internet, with some sites saying it isn't necessary and that the calculations are pretty simple and nowadays builders do them on a regular basis. But not sure it's worth the risk of avoiding a structural engineer, even if it will add considerable time and money to the project...

Anyone else knocked down a load bearing wall without a structural engineer? Good or bad experience? Am I being mad to even consider it?



BumgrapesofWrath Thu 17-Sep-15 11:19:53

If you don't get a structural engineer to do your calculations you will struggle to sell your house without them.

I know plenty of builders who think structural engineers aren't necessary, and yes an experienced builder will probably be able to come up with something that will work. But to be on the safe side i'd get the calcs done.

Justmuddlingalong Thu 17-Sep-15 11:22:54

Would that not invalidate your house insurance?

PigletJohn Thu 17-Sep-15 11:35:53

You are submitting plans for Building Control approval, aren't you?

The BCO will know at a glance if your specification of piers, padstones, RSJ and firecladding are sufficient (most builders overspecify "to be on the safe side" and the material cost will not be significantly higher)

If there is any doubt the BCO may ask for modifications. If you want to argue with her you may have to provide calculations, but the BCO will have seen hundreds of houses just like your doing the same thing, and probably dozens of them in your very street.

Sensible buyers will very that you have BCO approval (and planning permission if relevant). The engineers calculations are not needed.

PigletJohn Thu 17-Sep-15 11:37:15

BTW removing the door and wall between your house and your conservatory will not meet BRs.

PigletJohn Thu 17-Sep-15 11:37:43

due to energy wastage

KatTwam Thu 17-Sep-15 11:45:41


Thanks for your responses.

If removing the wall between the conservatory and house will not meet the BRs, I would rather not attempt it! There is already heating plumbed into the conservatory (it was there when we bought the house) and we are changing the roof to one with a higher U value and inserting extra insulation in the wall parts and in the floor and we have installed solar panels on our house to reduce electricity usage etc. etc. But perhaps regardless of all this, they won't accept?

Thanks, K

RaphaellaTheSpanishWaterDog Thu 17-Sep-15 11:58:20

We didn't.......BUT, we did use an architect who knew from many years of experience what size steels were required, we did get building regs and our (independent) building inspector signed it all off without raising any issues before we sold the house last year.

This was for a bonafide extension btw, not opening up a kitchen into a conservatory.

KatTwam Thu 17-Sep-15 12:05:02

Having looked through other threads, other people have passed BRs for similar work after they increased the insulation in the conservatory and/or in the house as a whole. We are already doing that, so hopefully will be fine.

Having looked at BRs in our borough, you can start work 24 hours after you apply before you pass? This seems rather bizarre. And they also offer retrospective BCO, which obviously one shouldn't rely on.

Anyway, thanks all for your advice. I will have a chat with BC in our borough and see what needs doing.


whatsthatcomingoverthehill Thu 17-Sep-15 14:48:03

As a structural engineer I may be slightly biased here....

A lot of builders, particular those who do house extensions, think they know best. And to be fair a lot of the time what they do will be OK. But what they don't seem to look at is the wider picture. e.g. Do they know the right padstone size to use? Have they considered overall stability of the house (if the opening is too big/there isn't enough wall left)? A self employed engineer will not charge a fortune for the design, a couple of hundred maybe, can show you people in your area who do that sort of work.

And absolutely speak to building control to see what you can do. I would be very surprised if it would meet building regs with an existing conservatory. I know someone whose kitchen is open plan into the conservatory and it is terrible. Freezing in water with loads of condensation build up (christmas presents got mouldy...) and sweltering in summer. For maybe a third of the year it's ok.

whatsthatcomingoverthehill Thu 17-Sep-15 14:48:45

In winter not water!

KatTwam Thu 17-Sep-15 15:13:43

Thanks whatsthatcoming, our conservatory is north facing and so not boiling in summer. It has been chilly in winter, but as I said above, we are putting in a new roof and insulation so I am pretty confident it will be fine. Either way, you think it will not meeting building regs? I have found examples of other mumsnetters who said they did get building regs to knock down a similar wall. Could it depend on the borough you live in?

whatsthatcomingoverthehill Thu 17-Sep-15 15:32:42

I think to prove it is OK from a thermal POV you will need proper calculations done (think they're called SAP). With a new roof you might have a chance. Other issues might be that it isn't classed as a conservatory any more but an extension and Building Control might start getting funny about things like foundations.

poocatcherchampion Thu 17-Sep-15 15:35:09

Our builder did the calculation. We had building control sign it off.

KatTwam Thu 17-Sep-15 15:41:21

Hi poocatcher, was this a wall leading into a conservatory? thanks K

KatTwam Thu 17-Sep-15 15:42:29

No, it's definitely still a conservatory I think, as the new roof is glass. There is one complete wall and then two 1/3 walls under windows.

whatsthatcomingoverthehill Thu 17-Sep-15 15:48:44

I mean it's not a conservatory from a Building Regs pov, because it is open into the house. Conservatories are exempt whereas extensions aren't.

Titsywoo Thu 17-Sep-15 16:37:12

I would call Building Control and ask

lalalonglegs Thu 17-Sep-15 22:09:28

Our building regs department won't sign things off without structural engineer calculations.

LBOCS2 Fri 18-Sep-15 11:33:53

When we knocked down a load bearing wall, we got a structural engineer to do the calculations and it really wasn't that expensive - about £450. For the sake of everything going smoothly, I'd definitely pay that again.

worldgonecrazy Fri 18-Sep-15 11:40:54

We had a structural engineer do some calculations when we took out a load bearing wall. It cost us £86. The architect had done most of the work already (architect fee was £400).

KatTwam Fri 18-Sep-15 13:24:48

Thanks all. Yes, I think for peace of mind its best to go with a SE! In the grand scheme of things, £450 is not that much (hopefully it won't be much more than that!)

KatTwam Fri 18-Sep-15 13:33:00

Actually our local SE charges £220!

Roseandbee Sat 19-Sep-15 23:58:17

i'm in the process of buying a house thats had this done. The seller didn't have the building regs so my solicitor got them to get the council out to sign off the work, they needed a SAP calculation but the conservatory was signed off as well as the RSJ which I think had to be exposed:-?
But i was actually quite surprised that the conservatory extension did get building regs approval, which must mean its classed as an extension now?

ShouldHavenotOf Sun 20-Sep-15 12:34:28

I would get the calcs done and make an application to building control - you're in breach of the regs if you don't and also it will cause you problems when you come to sell.

Others are right in that your conservatory being open to the house will not comply under Part L. They will ask you for a 'SAP' calculation to justify it, which I would think you will be able to do, given the other measures you're putting in place. You can do the SAP yourself, if you're savvy, or else get an assessor to do one for you.

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