Helibar fixing?

[paulbandler]

I've got evidence of a bit of movement in a bay window. Now perhaps I should get a structural engineer to advise (subject of another thread), but am considering having the builder who is already on-site put some helibars across the area where it has cracked. I notice from information elsewhere that Helibars are fixed into mortar beds with Helibond grout (http://www.helifix.co.uk/mainpages/helibond.htm) and that is is a cement based substance. Now I had been advised by someone (a lime plasterer no less - very rare species in these parts) who saw the problem that the helibars could/should be installed on over an area including brick courses below the DPC.

The question in my mind is whether this helibond grout would cause problems for the expiration of moisture from such brick courses as it presumably makes the surrounding mortar imporous.

 

[Johneds]

I don't think a small strip of cementitious grout would cause any problem whatsoever. Vapour and moisture will find a way out as long as there is a way. It's large impervious areas that cause the problems.

What I would say is that you should think carefully about where the stress is coming from - to cause this cracking - and be certain that fixing helibars will not just shift it elsewhere. How old are the cracks? It might be that just pointing with a good flexible lime mortar might do the job.

 

[paulbandler]

How old are the cracks?

Difficult to know as only just bought the place. Suspect they are quite old but there is evidence that a simple filling repair was attempted earlier and that it has moved a little more since.

 

[NT]

A small amount of movement in a bay window does not strike me as a big deal. Bay windows dont hold other parts of the house up. I'd just use lime mortar which can accomodate movement happily. Which is how it was designed to behave in the first place.


NT