Brick Stitching on Heritage Properties - Lime Mortar ?

[rideforever]

Got a crack on the back wall of the victorian flat, going to do slanted 8mm holes 20cm long to pin it with helical stainless steel. Upwards and downwards.
What do I put in the hole with the ss - resin ?
Or lime mortar ?
Or have a ready mix Cementone repair concrete but sets hard.
Or can I just get a bag of lime and mix it into the Cementone ? What proportions?
Concerned that to put hard stuff in an old wall will cause more cracking.
Cheers for any help

 

[^woody^]

Helical bars need to be set in the proprietary resin and then you would point the face with mortar to match the existing.

Definitely don't use repair concrete. Lol

Are 200mm the correct product? They sound like cavity ties. Normally the bar should be 500-600mm each side of the crack.

Has the cause been diagnosed and dealt with? Otherwise walls can crack somewhere else.

 

[rideforever]

Helical

Thanks ... it's a small area its a 1st floor back of the house kitchen wall (over an extension) next to a bay window.
Wall is 600mm wide. And it has 2 cracks - first at about chest height, 2nd one about 1/2 metre above that.
And on the inside there is a crack All horizontal.
So basically its been there for ages though I would just get a long drill bit and drill vertically at shallow angle and purchased 3 metres of helical ss.
I think if the drill bit was longer than 20cm, angled shallowly it would be hard to get the right angle.
I was going to get some nhl 3.5 and cover the bars in it and put them in.
And not resin.
Afterwards repoint the lines.
Neighbour had same issue, area has movement is close to beach.

 

[^woody^]

What, horizontally cracks? These don't need stitching.

 

[rideforever]

What, horizontally cracks? These don't need stitching.

So what do I do repoint ?
If I repoint it's 1/3 of the brick width isn't it, but is it worth drilling full width say to do 2" all the way through, then a 4" section only 1/3 width, and repeat along ... i.e to put a few teeth that go all the way through??

 

[Ivor Windybottom]

A photo would be useful.

 

[^woody^]

So what do I do repoint ?

Yes.

If there is ongoing movement to cause horizontal cracking, you have bigger problems than any Heath-Robinson repair will be able to solve, and you'll need to deal with the cause not the symptom.

Generally, any crack repair involves deeper raking-out than that with basic repointing. For wide bed joints you'd renew/fill as much as possible.

 

[rideforever]

A photo would be useful.

mortar rakes come in 4cm or 6.5cm so I could do
6.5 all the way along and drill through 2" per brick or something

 

[Ivor Windybottom]

Isn't that just render with some fake joints scraped into it?

If so then there possibly isn't any structural movement, it's just render cracking as it always does. But you'd need to get the render off to tell, it's probably brick underneath.

If it bothers you then the one fix is to take the lot off and re-render with a modern product including an embedded mesh. After fixing whatever structural issues if the bricks beneath have moved.

 

[rideforever]

No it's the bay slightly moving in the wall, on the interior there are also small cracks and slight movement on the outside by 1mm. Render alone won't fix it.

Just had a builder in here, he's booked until June so it looks like I will have to do something.
but he mentioned sticking in a helical bar on the upper horizontal crack with resin ... sounds easy, but how deep does it have to be can I remove mortar along the entire line to 4cm deep and stick it in, or do I use a 6.5cm (size of mortar rakes) or deeper ? At what point does the wall fall down ?
Or should I just repoint and forget the fancy stuff ?

 

[Charlie George]

Until you remove the render in damaged areas first, you (or anyone else) won't know what needs doing, or are you attempting to stitch the render together?

 

[rideforever]

@Charlie George
Yes, I think I'll take the render off half a line and scrape at it see if any is loose and then repoint 4cm in those areas - otherwise leave it - and put the render back on, working progressively until its all done got lots of time on my hands ... That's all. If it cracks in the future maybe something more. Simpler than I thought.

 

[ree]

OP,
You have Ashlar render FWIW.

Mirror cracks are no bueno but given your cracks are longstanding then I doubt that there's any rush for remedial work.

The horizontal cracks you indicate - are mirrored inside above the Bressummer Beam that lintels the opening below.
There's very little weight above your Bressummer Beam but the the supported ends of timber Bressummer beams can typically begin to fail due to moisture penetration. Any signs of internal damp?
The state of the bay roof eaves suggests that the bay roof & its flashing might also be in a poor condition?

The vertical cracks at the outside corner are possibly caused by the corner bead failing. Check for plumb with a level?
Also check for a rusting corner bead?

Perhaps the bay is leaning forward a few mm's - check for plumb. Properties like yours often have basements and lots of openings in the elevation.

 

[Ivor Windybottom]

IMO it's obvious that the render has expired its lifespan. It's lost its adhesion to the substrate so there's no point trying to patch it. Besides, render patches are never invisible, it would always look botched.

Do it right or don't bother. Strip it all off, fix any underlying issues then get it rendered with a modern product incorporating a mesh.