Rat-trap wall strengthening

[stout]

I have a 2.67M high garden rat-trap bond wall, it is constructed in Victorian brick and black ash lime, a lot of the pointing has been weathered away. It seems quite straight but has experienced movement over the years. My new neighbours have just started rendering their side with cement and concerned that this will hasten it chances of collapse. I know of 2 people having similar type of wall collapse in my area. My garden floor is approx 0.75m lower than my neighbours, I have an immaculate original bay window 1.5m away from this wall and want to strengthen the wall in this area to prevent damage.
What is the best method to protect my window other than taking the wall down.
I have thought of sinking angle irons every metre for a span of 4 metres and tying them into the wall then re-point it with NHL3.5 lime. How deep would these need to go or if I were to add brick pillars how thick and deep would these need to be to support a wall this high?

 

[tony1851]

You are right to be concerned; coating a free-standing wall in anything (even paint) is not a good idea and will certainly hasten decay of the brickwork.

Why your neighbours should even want to render a rat-trap bond wall is a mystery as those things are not that common.

As regards strengthening, it is unlikely angle iron will do. You really need weight to counter any overturning tendency and this would suggest brick piers.
Those would need substantial footings to ensure that they actually support the wall rather than pulling on it and making the situation worse.

At 9ft high on your side, you really need to speak with a SE to come up with a proper scheme.

 

[Nige F]

Strangely , I was looking @ a rat trap wall today - round an old vicarage ( waiting in the car while Mrs. shopped ) and there were buttress walls @ intervals along it - they didn`t go right to the top of the wall - so a structural engineer seems like the person to consult

 

[^woody^]

You say the neighbour is rendering their side, and then mention taking the wall down. So who actually owns the wall?

There needs to be a specific problem with the wall for you to address with appropriate work, random pointing or fixings of angle iron or anything is not really worth considering unless there is an actual problem