Major crack in brickwork

[bob52]

Hi Everyone,

I'm hoping you might be able to help me with a worrying problem with my 1950s traditional detached house. There is a vertical crack in the external Rockwool cavity filled wall, behind which is the internal load bearing wall dividing the front and back of the house. The roof is a purlin type which I am told is excellently constructed. In the exterior panel between the two chimney breasts is a crack which starts off with a loose brick at the top to the left of the right hand chimney breast. The crack then steps across to roughly the middle of the panel where it drops vertically until it stops 3 feet from the ground.

There are loose and cracked bricks at the top of the wall in the left bedroom and a crack in the corner all the way down to the floor. There is also a crack across the wall where the wooden wallplate meets the brickwork, but I have been advised that this particular crack is common and not a problem.

In the lounge below there are loose bricks at the top and cracks radiating from the corner and loose plaster which I have now knocked off in an attempt to see what is causing this.

I would be extremely grateful for any thoughts on what might be going on here! Photos of it all are attached.

Thank you.

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[^woody^]

You have had some contraction (ie shrinkage) of the wall.

The external crack is a a weak point due to the poor bond of the header bricks. It looks like it has been there a while and re-pointed previously

The internal one a a common place where shrinkage cracks occur, and again looks like poor bonding has not helped

 

[bob52]

Hi Woody,

Thank you very much for the information.

The headers are actually half bricks (I am told) as it is a cavity wall. In your opinion, would it be wise to attempt to improve the bond by not having half bricks in the centre of the panel i.e. where the load bearing wall joins?

The load bearing and interior walls are hollow clay blockwork - I am assuming that this is a difficult block to tie to, could this also be part of the problem i.e. insufficient or poor wall ties? Would you have any suggestions as to how this could be improved?

Cheers, Bob.

 

[^woody^]

You wont alter the brick bond now, as that extra 100mm (ie the half brick) has to be somewhere in the wall, and whoever built it has messed up the bond, as the half should be at the end - they've done what is known as reverse bond and[/] got a half in the wall - a double fail!

You will have to do some brick stitching with stainless steel helical bars fixed with resin - google for Helifix or the cheaper Twistfix systems

Same scenario for the internal wall - you'll need to tie it with bars and resin to control any future movement, which BTW should only be slight as it's probably done the worst of it now