Rubble filled wall restraint

[Morninglory]

Hi,

A survey has found a rubble-filled stone wall in our terrace needs strapping to the side walls and floor of the structure. The detail the engineer has recommended involves cutting out a big chunk of the inner leaf, drilling and gluing standard ties into the outer leaf, casting a 300mm cube block of concrete in the wall with the ties cast in, then in turn strapping the new concrete blocks back to the side walls and floor. Sounds simple enough, as long as they're not all done at once and the house falls down. Anyone done this, got any photos or advice?

Thanks in advance

 

[Deleted member 292770]

can we see the paperwork / pictures?

 

[Morninglory]

 

[^woody^]

I suppose its very similar concept to underpinning in terms of working in bays.

Under CDM regulations, your engineer should be providing a method statement detailing how this should be done.

 

[KenGMac]

Suggest a look @

https://www.helifix.co.uk/case-studies/repairs-to-grade-ii-listed-rubble-filled-stone-walls

If the joists are running Parallel to the wall Helifix do a different bore in system.

Ken.

 

[Morninglory]

This is all really useful, thanks. I'm hoping to put some steels in for changing the internal layout so will be using the same engineer. I'll ask them for a method statement regarding how the detail needs constructing and the order to do them in.

 

[Deleted member 174758]

I'll ask them for a method statement regarding how the detail needs constructing and the order to do them in.

You'll need it. When you cut into rubble filled walls like that you can end up with a lot of the loose fill just falling out.

 

[KenGMac]

Must admit, I agree with Jobandknock above, random filled walls are a real pain.

The core fill is loosely held with [generally] old lime Mortar so as such will simply fall out.

Up here there are thousands of old sandstone faced tenements, the external facade of masonry can and does bulge outwards away from the fill core.

I suppose one way of [to a certain extent] stabilizing the core would be to inject a cement or resin into the core matrix, let it set then cut in to it??

Bluntly the proposal as per the drawing above does not fill me with any confidence whatsoever.

Ken.

 

[Deleted member 174758]

I suppose one way of [to a certain extent] stabilizing the core would be to inject a cement or resin into the core matrix, let it set then cut in to it??

Bluntly the proposal as per the drawing above does not fill me with any confidence whatsoever.

We had one building where the main contractor had to cut 6 new openings into the back walls of what had been a bank - stone building from the 1860s but rubble infill walls. The first hole that was cut for a new lintel to be installed was disastrous with about 2 or 3 tons of loose infill (about half a skip full) coming out before stopping. The masons doing the job damn nigh crapped themselves - they thought the flow would never stop!

When it finally did we had to shutter it off and drill a load of holes on the insides of the walls through which some sort of concrete with a fibre admixture (?) was then pumped for that one and left to set a few days, then another batch a few days later further up the wall, and so on a few more times up the wall until they found rubble infill again. The rest of the cut-outs were done by first drilling through the walls just above where the new lintels were to go and injecting some sort of cement epoxy resin with a fibre binder (?) and allowing it to set before proceeding. Which is what we should have been instructed to do in the first case. All a bit hairy.

My involvement was to set the levels and form the shuttering for the padstones, so if I am not 100% accurate on the materials used I apologise, but that really wasn't my part of the job.

After the shuttering had been struck we went back and drilled through from the insides to the outsides and installed stainless steel twist ties and loads of resin to tie the walls together. It's still standing, but it did seem a bit iffy at the time. Needless to say all this was under instruction from the S/E and architect