Blown render removal.!

[sirius5e]

Hi all, i have removed some blown render from my gable wall to reveal a vertical crack .
The crack has been visible for some years and has not widened.
My question is what do i do next ?
Slate wedge any gaps and fill in the spaces where the old garage lintels were.
Do i simply patch in and form my own rough cast like the rest of the gable or is there alternatives.
Thanks in advance for any input.
Pictures below.
//www.diynot.com/network/sirius5e/albums/9170

 

[sirius5e]

Can anyone help please ?

Do i apply an external pva to the brickwork first or add it to the first mix and what about waterproofer etc.
Its daunting enough without the real knowledge of how to and why.

Untitled

• sirius5e
• 23 Jun 2011
• 1

 

[Micilin]

If you drop a plumb line from top to bottom, in the middle of the crack, what is the furthest from that line the crack reaches each side?

You may have to put a movement joint in, but the above will help as how best to do this

 

[sirius5e]

what is the furthest from that line the crack reaches each side?
140 mm .

 

[joe-90]

Couple of stitch bars every three courses should sort it.

 

[Micilin]

If 140mm each side then I would mesh each side of this , and put a movement joint in the middle, so that the control joint takes up the movement.

To explain better, you have two pieces of mesh, each at least 250mm wide ie at least 100mm past the furthest extent of crack They are fixed each side of the middle line of your crack , 10 mm apart.
You then fix a 10 mm stainless steel stop bead each side of the 10mm gap ( 'back to back ' ) . All movement of the crack behind the mesh won't matter, as each side can move independently and the mastic you place in the 10mm gap after rendering can move with the wall.
In effect you are extending the 'wing' of the beads to cover the crack

-------- ----------------- wall
. ...... ...... mesh
. . . ~ ~ beads

There are other ways of doing this, such as a deeper bead on first and lapping the mesh onto it, but to me this is simplest.

You could also sue an integral expansion bead ie one bead with rubber strip in middle

 

[joe-90]

http://www.twistfix.co.uk/products/masonry-crack-repairs/masonry-crack-repair-kit-product.html

 

[Micilin]

http://www.twistfix.co.uk/products/masonry-crack-repairs/masonry-crack-repair-kit-product.html

Joe, with these you have to cut out every three courses?

 

[joe-90]

Grind out every third mortar course. That's how they repair under insurance.

 

[Micilin]

Grind out every third mortar course. That's how they repair under insurance.

Doesn't the length of wall need to be taken into account as well?

Do they recommend a max ?

Sometimes you have to allow the wall to move , but control where it does so.

 

[joe-90]

No. It just spreads the load - simples.