Damaged reinforced concrete lintel - what to do?

[Beginerz]

Hi all.

Brand new poster here. We are doing up our first home and removed an old conservatory a few weeks ago which spanned most of the width of the rear of the house.

The house was built in the early 60s. You will see there is what looks like either a pre-stressed or reinforced concrete lintel which spans the back of the house. Not sure if it's just a rectangular shaped lintel or a boot lintel going back where we can't see.

After removing the conservatory we discovered that part of this concrete lintel has been cut near the downpipe where they had attached the conservatory. Not only have they cut part of the concrete but also one of the steel reinforcing bars which runs inside the lintel. The exposed steel looks to have corroded a bit and there is a gap where the bar/rod has been cut of some 6 inches approx.

I can only hazard a guess from where this steel bar is within the lintel that there may be probably two more bars/rods further back in the lintel in tact which are not visible.

We are wondering whether to get a structural engineer to have a look and see what might need to be done to make sure the house has structural integrity going forward.

Any help or advice would be much appreciated. We had very much hoped the house was structurally unaltered dispute this old conservatory and have found this on removal which has left us not knowing what might need to be done.

Thank you.

 

[^woody^]

Clean the rebar, apply a rust converter (K-rust, Jenolite) then make good the concrete with an epoxy concrete repair product.

 

[Dereekoo]

Clean the rebar, apply a rust converter (K-rust, Jenolite) then make good the concrete with an epoxy concrete repair product.

That won't restore the structural integrity of the slab but it will look nice and perhaps stop you fretting over something that seems to have stood the test of time.

 

[Beginerz]

Clean the rebar, apply a rust converter (K-rust, Jenolite) then make good the concrete with an epoxy concrete repair product.

That won't restore the structural integrity of the slab but it will look nice and perhaps stop you fretting over something that seems to have stood the test of time.

Would treating the rust and then welding a a piece of galvanised steel to span the gap help with the structural integrity? Or would this be pointless if the existing steel was pre-stressed?

Could there be any other remedy such as having a few rows of bricks removed from above the lintel where it spans above the (living room) and fitting a steel lintel above on this side between those two cavities?

 

[Beginerz]

To add having read further info on these forums I suspect this concrete lintel is unlikely to be pre-stressed.

Therefore could it be worth welding a piece of new rebar in to bridge the gap before building the shape of the lintel back up?

Does anyone know the potential price for a structural engineer to inspect a single item such as this?

 

[^woody^]

That won't restore the structural integrity of the slab but it will look nice and perhaps stop you fretting over something that seems to have stood the test of time.

What structural integrity has been lost?

That soffit has been like that for god knows how many years, and it's only the nosing which has been broken, not what looks like the other 600mm or so of bearing.

 

[Beginerz]

That soffit has been like that for god knows how many years,

30 years at the very least we suspect, as there was real linoleum fitted to the conservatory floor.

 

[Ivor Windybottom]

Think you're suffering from homebuyer's panic. If it hasn't fallen down then it's probably fine.

Your idea about welding to the rebar would cause more disruption than has already happened. You've no idea what will happen internally if you heat the steel to melting point, plus you'd need to strip away lots of concrete to access it.

Just tidy it up and preserve the bare metal, as suggested by others above, pour a nice drink, relax and enjoy your home.

 

[Beginerz]

Think you're suffering from homebuyer's panic. If it hasn't fallen down then it's probably fine.

Your idea about welding to the rebar would cause more disruption than has already happened. You've no idea what will happen internally if you heat the steel to melting point, plus you'd need to strip away lots of concrete to access it.

Just tidy it up and preserve the bare metal, as suggested by others above, pour a nice drink, relax and enjoy your home.

Thanks.

Yes there is an element of homebuyers panic as we had to walk away from a previous purchase of an identical house nearby where they'd knocked down an exterior wall all the way along the back for an extension and surveyor couldn't identify what was then holding the back of the house up as he said there's no RSJ and the old lintel could not be seen where he felt it should have been. No building regs for it either.

So the idea here was to try and find an example which hadn't been messed with but soon as the conservatory was removed we found it had been messed with!

How many rebars would technically be needed to maintain the structure of a lintel like that? I would hazard a guess there are probably two more running through it.

 

[opps]

How many rebars would technically be needed to maintain the structure of a lintel like that? I would hazard a guess there are probably two more running through it.

No my area of expertise... but... from memory when I have cut 9" ones, there were three rebars.

 

[Beginerz]

Saw this....

Could helical bars fitted above guarantee the integrity even if this lintel was to begin to fail in the future?

 

[Beginerz]

No my area of expertise... but... from memory when I have cut 9" ones, there were three rebars.

Out of interest what were you cutting them for?

 

[Ivor Windybottom]

Most houses have been messed about with in some way, many more were built with issues from day one. It's all normal.

You seem to think there's an unexploded bomb under it. As the wall hasn't fallen down it's probably OK to assume it's adequate. There will be masses of margin in the strength of the lintel. Most lintels don't even have that lip that juts out, which is the only part that's been trimmed back.

 

[opps]

Out of interest what were you cutting them for?

It was a mate's house. He wanted to change an external door into a double door. The new lintel was about 30cm too long. I used a 9" grinder to cut through it.

Apropos helifix bars- As a decorator I use them quite often when dealing with cracked masonry window sills.

I believe that when reinforcing brickwork, you need to span 3 bricks in either direction from the crack and use them every 2 or 3 courses up. A brickie can offer more definitive advice though.

When working with them, I use a diamond blade on an angle grinder to cut the slot and to trim them to length. I then use anchor bolt epoxy (in a cartridge gun) to fit them. In your case though, you will need to try to colour match the sand and cement, oh, and then learn how to point- whereas I am just using filler that will be sanded back and painted over.

If it is just shrinkage, the helifix bars may be overkill.

 

[Dereekoo]

What structural integrity has been lost?

Well if its just part of the nosing nib and not structural in either bending or shear I would have to agree none and as stated, whatever the implications, are the test of time would suggest that it has enough structural integrity to perform the necessary requirements