Replacement lintel help

[PAFCBOY]

Ok I'll try and paint a picture.

I have a 1930's detached house. It is cavity block construction and rendered and painted white. In the gable end are various Windows. They are double glazed (formerly sash) and are sunk about 150mm into the gable. Each has a sloped masonry window ledge that projects over the gable end.

I've had a problem with very bad cracking over two of the windows. To cut a long story short I have found a couple of rusted steel bars are the cause. Their rusting and expansion has caused the severe cracking. I assume they are reinforced lintels that have disintegrated with water penetration. I can see another steel bar in better condition on the inside course. Could they just be tie bars then?

In getting the rusting outside bar out, I've not damaged the top face of the recess. I've propped it with a wooden prop just in case. There's the top face of the recess, about 50mm of surviving render/block above then a gash (50mm-80mm wide) where I've removed the rusting bar. I now have a 5-8 cm gash above the window although 5cm of the top face and above of the recess looks intact ...... and remarkably ..... sound I guess I need to install a new concrete lintel? Correct?

But .... The windows are recessed 150mm from the face of the end gable. Do I demolish the top face of the recess that's survived my handy work and replace with a lintel measuring 150mm wide plus a block widthor do I install a lintel above the surviving 50mm of top face where the gash is (obviously overlapping the window width).

If a photo would help I will post?

Sorry for my ramble! And thanks in anticipation for any advice

 

[wessex101]

As clear as mud....a photo would definitely help.

 

[PAFCBOY]

First photo = the other window needing attention.

Second window = my attack with a hammer an bolster to remove rusty rod either being a rebar or remains of a lintel? I'm peeling back temp waterproofing!

 

[wessex101]

First question, are you sure it is not some kind of PRC or Mundic construction?

Secondly if it is just a concrete lintel then probably easier to cut out the entire lintel and replace like for like.

Forgot to say obviously checking it is not a boot lintel that goes right through to the inside face of the wall. If it is a boot lintel just cut off the outer toe and replace that.

 

[PAFCBOY]

Its block construction and when we bought in 1997 we had full survey and cores were drilled and sampled for mundic and negative.

Can I ask: will the bottom of lintel be the bit I've propped and also sit further into the wall. I.e the propped bit is 150mm wide so how wide a lintel would I need. Is this a job for builder or would a reasonable confident if not competent diy'er cope. On face of it it looks an easy job once I know what I need to do!