Help: sandstone lintol failure

[Broondog]

Hello, exactly 1 year after moving in to our terraced house in Glasgow, we've been unlucky in that the roof has leaked and last month we noticed that our main bay window lintol has failed.

The house has a red (locharbrigg?) sandstone makeup. There is a vertical crack as the lintol adjoins the RH mullion.

I have had 3 builders out;

2 independent stone masons who are sole traders
1 large building firm with all the bells and whistles.

Thus far, I've had 3 different proposals to remedy this;

1. USe of e.g. 16mm stainless steel bars driven in at angles
2. Use of stainless steel bars cut into the face iwth a grinder
3. An L section bar (3"x3") on the leading edge of the lintol.

Options 1 & 2 have discreet finishes as they are buried. However, I'm concerned about their structural integrity.

Option 3 is by far the most robust in terms of structural reinforcement.

The dillema I have is thirce;

1. The wife does not want any visible bar. Nor does she want to pay £1.5k to the contractor for option 3.

2. The cheapest options scare me in terms of structural stability

3. The remaining option for circa £1k, is to have the sandstone lintol replaced with one made up. This is obviously the preferred solution but using a sole trader to do this worries me with regards to insurances etc as it has such poteniallly devastating consequences if they get this wrong.

How do I choose the correct solution - HELP HELP HELP. I have put a picture in my album

 

[theoldun]

You say you noticed the crack last month. Could have been there 20 years.
You say the lintel has failed. If it had failed it would be lying on the ground now.
Have been in this game much to long now, but in our honest opinion what with the structure and design and workmanship of your bay it will stand at least another 100 years in it’s present condition.
How ever to put your mind at rest. Reckon the window cleaner suggested option 2 as it will stand out like sore thumb and the bin man option 3 because he possibly does not like you.
Option 1 is the one to possibly go for with Helifix cemties through the mullion and into lintel.
Although we would go with two cemties at a 45 degree angle from the lintel soffit up into mullion and two cemties from the lintel soffit up in to the corbel and brickwork above, at say quarter in from mullion.
If lintel did go full depth of wall, would do the same inside, although would think that inside is either cast in situ concrete or possibly timber bresummer.
Google Helifix and have a read.

oldun

 

[Broondog]

Thanks for the input. To be clear, the high resolution digital images of the front of the house show no crack at all - sorry to be rude but it has just failed. I use the word failed as its broke and any structural member that is broken is clearly not taking load ni the correct manner - again, bit blase of you. Finally, the crack is right beside the mullion so the pinning is more dangerous as the small section on the lintol could just pop off.

I see you did not recommend replacement - is that way too OTT?