Damaged reinforced concrete lintel - what to do?

[Beginerz]

I should have written that beams are stressed most in bending near the centre of the unsupported span. The amount of bending where the notch is will be small. Unless the your new bar(s) are welded to the existing one there will be no increase in overall structural integrity. I wouldn't try to put in new bars because I think it will compromise the repair to the concrete.

I am a retired structural engineer. i specialised in steel structures but the underlying principles of all structures are the same.

Thank you. Yeah I accept that trying to weld to the existing bars is a definite no no after advice from the forum.

The helical bars I am wondering about are these as posted earlier on....

They seem like they are a way of providing strength above within the bricks, where there is some sort of failed lintel below.

Would this not be suitable here?

 

[PBSpears]

Cracked brickwork is a sign of structural failure. I'd seriously consider a system like that if I had cracked brickwork, but I looked and couldn't see any. So I don't think it's necessary. If you decide to do it just for the ultimate belt and braces then I would recommend propping up the unsupported span while the work proceeds. This is because the act of removing the mortar weakens the wall temporarily until the reinforcement goes in and is fixed. Do the concrete repair after you put in the brick reinforcement just in case something moves slightly during the installation.

There is a danger water will get into the join between the new concrete and old which will rust the bar causing the concrete to stain or even spall off. Google concrete spalling repairs for lots of good info.

 

[Ivor Windybottom]

I'm guessing the conservatory has been there for 20 years or more. In which time nothing has moved anywhere, so it's had a rigorous actual real world test and is evidently fine.

The only unknown is what happens when you start removing more of it. Welding to the rebar or gouging out the pointing above are IMO far more likely to cause issues than just preserving it by rustproofing and filling.

Remember that any visiting experts usually make their money by doing work, not by saying it's best left alone.

 

[opps]

I cannot see anything to suggest that you need helifix bars.

Put them in if makes you feel better, but bear in mind that you will need to try to colour match the existing mortar- more difficult that it may initially seem.

 

[Beginerz]

I cannot see anything to suggest that you need helifix bars.

Put them in if makes you feel better, but bear in mind that you will need to try to colour match the existing mortar- more difficult that it may initially seem.

Would it be cracking in brickwork to justify helifix bars?

 

[opps]

Would it be cracking in brickwork to justify helifix bars?

Yes and no. Sorry, that doesn't help much.

It may be the case that you can repoint and all will be good.

That said, if you are going to have to repoint, yeah, why not fit helifix bars. They are about a tenner for 1m (6mm). You can get tubes of anchor fix for about £7. Three bars of reinforcement will cost about £55. Most brickies that I know only fit 1 helifix bar per course of bricks, as opposed to the two in your video. You also have to factor in the cost of angle grinding away the old mortar (although if the mortar is soft enough, you may be able hack it away).

 

[PBSpears]

If you put in the helical bar reinforcement then strictly speaking that constitutes structural work on the property which you have to declare when you sell it. That might put people off. Just putting a patch in the notch isn't a structural repair and isn't declarable.

 

[opps]

If you put in the helical bar reinforcement then strictly speaking that constitutes structural work on the property which you have to declare when you sell it. That might put people off. Just putting a patch in the notch isn't a structural repair and isn't declarable.

Are you sure?

I often use helifix bars when painting cracked masonry window sills.

I am only a lowly decorator. I have seen several brickies use them. None has ever told the customer that the work is notifiable, granted, that doesn't mean that it is not notifiable.

 

[PBSpears]

The way OP wants to use them is to rectify a structural fault. I don't actually agree there is a structural fault, but that's beside the point, OP seems to think there is. If the lintel was cracked and sagging, and brickwork cracked, then there would be no question that this is a structural repair and should be declared during the sale. Not sure if it's notifiable to building control or would be deemed to be covered by a competent person clause. The only way to find out for sure would be to ask building control, and that opens up a can of worms.

But the lintel / slab isn't sagging and there is no cracked brickwork so it's a bit unclear. If you think there is enough of a structural fault to fix it then surely you think there is enough of a structural fault to declare it. It's logically inconsistent to believe you have to fix it but not declare it.

Window sills aren't structural elements like lintels or brickwork so you don't have to declare them in that context.

 

[Beginerz]

Are you sure?

I often use helifix bars when painting cracked masonry window sills.

I am only a lowly decorator. I have seen several brickies use them. None has ever told the customer that the work is notifiable, granted, that doesn't mean that it is not notifiable.

The way OP wants to use them is to rectify a structural fault. I don't actually agree there is a structural fault, but that's beside the point, OP seems to think there is. If the lintel was cracked and sagging, and brickwork cracked, then there would be no question that this is a structural repair and should be declared during the sale. Not sure if it's notifiable to building control or would be deemed to be covered by a competent person clause. The only way to find out for sure would be to ask building control, and that opens up a can of worms.

But the lintel / slab isn't sagging and there is no cracked brickwork so it's a bit unclear. If you think there is enough of a structural fault to fix it then surely you think there is enough of a structural fault to declare it. It's logically inconsistent to believe you have to fix it but not declare it.

Window sills aren't structural elements like lintels or brickwork so you don't have to declare them in that context.

Thanks.

As you say there certainly does not appear to be a structural fault at this time. The only reason I have asked about helifix bars is because to be quite honest, while the place is empty and we are doing all the works, we'd rather go over and above and preempt any possible future issue rather than take the chance of suck it and see.

I realise the chance of any future fault occuring because of this may be relatively small, but I can only assume the bars inside the slab will deteriorate further regardless during the future and not stay the same as they are today (hence the state of the M6 elevated section around Birmingham and the fact they're always working on the concrete). And so if something can be future proofed now while we are doing lots of work then a part of me think it's worth considering just going ahead and getting it done.

I also get the impression that if signs of fault did show up in the future that we then may be dealing with something more serious than just having some helifix bars fitted. Is it not possible fitting them now could give a strong chance of avoiding that possible situation altogether?

Does anyone know whether a structural repair such as helifix bars have to be declared during a house sale? Is there a question on it within the standard property questionnaire? We had several purchases fall through before this one and on both the sellers left out odd answers from the property questionnaire and when prodded came back to say that's all the info we are prepared to give. Solicitor acting for us on one failed previous property purchase didn't advise that was unusual and said some sellers just don't wish to provide detailed information and no alarm bells.

To be honest our conveyancing solicitor pretty much told us it's buyer beware when purchasing and rely only on your own survey alone as once sale is complete there is little if any recourse. As we are finding out here, as the previous occupant had the house since 1960 and failed to declare they'd had the reinforced lintel part cut for a conservatory!

 

[^woody^]

Bear in mind that if you put heli-bars in, structural or not, just visually, at some time in the future if you come to sell up someone like me will say "hang on a minute, that's a structural fault that has been repaired" and then you will be going through the rigmarole of structural engineers and costs of trying to say that there is not anything actually wrong.

And don't compare a bit of damaged concrete on a house with what's going on at spaghetti junction!

You could have 'virtually' repaired that concrete and moved on with your life before you got on to page two of this thread.

 

[Ivor Windybottom]

Roads usually suffer structurally only because they have vast amounts of salt sprayed on the surface every winter, which inevitably makes its way down through the semi-permeable layers of tarmac and into the underlying structure. The same goes for concrete sea defences - salty sea water.

Unless you grit your roof or have the sea regularly lapping at your back wall then it's unlikely to suffer the same fate.

I think you're getting over-excited about a very minor mostly cosmetic issue.

 

[PBSpears]

I don't think there is much chance of further deterioration. The only mechanism I can think of is water ingress right through to the next bar, which I think is probably quite a long way back. Even if that occurs it still has to rust through which will take a long time. If you do a high quality repair water ingress will be prevented. I don't know the details of the M6 repairs but the usual problem is surface spalling exposing the bars closest to the surface, and the repairs they do are usually just a cover up to prevent further rusting and spalling.

If you decide to put in the helical bars they should be centred over the notch. It's not really my field but I would guess they need to be at least a metre long to be effective. Support the span, especially near the right hand end, while you put them in. I would put them in one at a time to reduce the amount of unsupported brick.

The relevant question is q4.1 on https://www.rlo.law/wp-content/uploads/2019/08/pif.pdf Past experience leads me to conclude that "building works" means anything structural. If a seller refused to complete that part of the form I would simply walk away from the deal. You would find it difficult to sue you the previous owner because they would just say they were unaware that the bar had been cut. Similarly, if you do a cosmetic repair, you can claim that's all you did and didn't think there was a structural problem.

If you put in the bars and the buyer spots them then you have to explain why and it all starts to get complicated. If you don't get a structural engineer involved it might be difficult to explain away. If you just do the cover-up you haven't actually done anything structural (though the previous owner did). If I spotted that when buying a house it wouldn't even occur to me to think that a reinforcing bar had been cut. I repaired some spalled concrete on a flat I sold and the buyer's surveyor didn't even notice it.

If you want complete peace of mind, get a structural engineer in. If I was called in my gut instinct would be to say that it is safe as it is. But then professional caution would kick in and I would do some calculations and and maybe a survey to find the residual strength of the lintel. If that was insufficient including the safety factors then you'd see if helical bars would be sufficient. The calcs wouldn't be too expensive, say less than £500. If a survey was required to find out what there is further back then you'd talking about taking the plaster off part of the wall on the inside.

Do you have concrete floors? If so the problem is even smaller than I had assumed.

 

[opps]

I don't think there is much chance of further deterioration. The only mechanism I can think of is water ingress right through to the next bar, which I think is probably quite a long way back. Even if that occurs it still has to rust through which will take a long time. If you do a high quality repair water ingress will be prevented. I don't know the details of the M6 repairs but the usual problem is surface spalling exposing the bars closest to the surface, and the repairs they do are usually just a cover up to prevent further rusting and spalling.

If you decide to put in the helical bars they should be centred over the notch. It's not really my field but I would guess they need to be at least a metre long to be effective. Support the span, especially near the right hand end, while you put them in. I would put them in one at a time to reduce the amount of unsupported brick.

The relevant question is q4.1 on https://www.rlo.law/wp-content/uploads/2019/08/pif.pdf Past experience leads me to conclude that "building works" means anything structural. If a seller refused to complete that part of the form I would simply walk away from the deal. You would find it difficult to sue you the previous owner because they would just say they were unaware that the bar had been cut. Similarly, if you do a cosmetic repair, you can claim that's all you did and didn't think there was a structural problem.

If you put in the bars and the buyer spots them then you have to explain why and it all starts to get complicated. If you don't get a structural engineer involved it might be difficult to explain away. If you just do the cover-up you haven't actually done anything structural (though the previous owner did). If I spotted that when buying a house it wouldn't even occur to me to think that a reinforcing bar had been cut. I repaired some spalled concrete on a flat I sold and the buyer's surveyor didn't even notice it.

If you want complete peace of mind, get a structural engineer in. If I was called in my gut instinct would be to say that it is safe as it is. But then professional caution would kick in and I would do some calculations and and maybe a survey to find the residual strength of the lintel. If that was insufficient including the safety factors then you'd see if helical bars would be sufficient. The calcs wouldn't be too expensive, say less than £500. If a survey was required to find out what there is further back then you'd talking about taking the plaster off part of the wall on the inside.

Do you have concrete floors? If so the problem is even smaller than I had assumed.

A brick is 4.5" thick (11.45cm). Helifix recommend burying the bar 2.5-3.5cm deep. The polyester resin used to fit them will cure within 20 mins during the summer. I have never seen a brickie support a wall during that process. It is not far off the depth that a pointer will dig out prior to repointing (on Victorian property).

 

[PBSpears]

I was just going off the video which seemed to indicate two bars per course and presumably a deeper slot. The rental cost of 2 acrow props is trivial. OP seems fairly risk averse and I was just trying to reassure him.