Brickwork cracked behind render

[Bri44]

Hi all

I’m having cracks repaired on my render. They have cut the render back to the brickwork and I’ve noticed the crack is all the way through the brickwork.
It is 18 foot long vertical which does an L shape in middle.

other smaller repairs have cracked brickwork also.


is this subsidence?
The house is built on clay.

If they simply fill in with render I guess it will just crack open again.

 

[KenGMac]

Bri44, good evening.

Did the crack in the render mimic the crack in the blocks?

Does this crack extend 18 feet vertically?

How long is the elevation on which this crack is sited? and is this crack [Approximately] sited centrally on the elevation?

Looks a lot like an expansion crack? not Subsidence.

Ken.

 

[Bri44]

The crack looks to mimic the crack in the render. There are more cracks.
The 18 ft vertical crack in this picture is the main one with the cracked block work. The top crack in the picture.
However, they have cut the render out horizontally from this crack in 2 other places.

If it is an expansion crack, what are the consequences and the fix?

 

[KenGMac]

How long is that elevation ? OK it is 18 Feet in height

I do not see any purpose built "expansion joints" in the image posted, is there one?

In any "large expanse" of block work and brickwork there should [have] been purpose built, at the time of the construction, expansion joints built in as the wall itself is built.

How old is this property?

Ken.

 

[Bri44]

The building is 40 plus foot high. That main crack is 18feet in length coming down the house.
They have cut two other channels out from this main crack that I`ve marked in blue.
the expansion joint I`ve marked in maroon colour. It goes from the ground to the window. Then a gap and starts again higher up.
The expansion joint is 13 feet from the right hand side/end of the building.
The house was built in 2013.

 

[dontbelieveawordofit]

did you contact the house builder or get a survey done beforehand .

 

[Bri44]

It is the developer who is carrying out the repairs. It has taken 3 years to get to this stage. Their customer services have just been out to see these cracks. Now I`ll wait to see what the higher up in the chain has to say.
I bought the house as a new home, I never got a survey as I expected it to be problem free being a new house.

I`m wanting to know what the fix would be.

Should the developer now arrange a structural survey?

 

[dontbelieveawordofit]

yes 100% . and if they refuse get your own done before they re-finish the outside.

 

[Bri44]

I`ve not heard back from the developer but the render repair company has said they will mesh the cracks before filling in with render.
The image showing the 18 ft crack you can see the 4 ft crack below it. That crack goes all the way up and meets the 18 ft crack so the crack is from top to bottom. Wider at the top.
The render company said its expansion cracks.
Should they investigate further with a survey or is the mesh the correct fix?

 

[KenGMac]

Bri44, good evening again.

Yes to a Structural engineers appraisal of this situation.

As a general rule, on an elevation such as yours any expansion joint MUST be continuous over the full height of that elevation, with as little "deviation" as possible from the vertical.

It would appear that because on your elevation, the purpose built expansion joint is not continuous that in and of itself is causing thermal stresses to accumulate causing secondary cracking in other areas of the elevation.

OK in "general terms" the design of the block is undertaken by the Architect, [fine] the nuts and bolts of the structural elements are prescribed by a Structural Engineer, obviously this entails the overall make up of floors and walls, as far as walls are concerned, the Engineer has to design the external walls to withstand wind pressure, the wall may have to transfer a load from the various floors and because block work WILL expand and contract provision for the safe and controlled "releaf" of such stresses based on the strength of the blocks, and the strength of the mortar mix has to be assessed and expansion allowed for, by way of construction expansion joints at regular intervals over the length of the elevation.

If there is a section of "Missing" expansion joint then the "Builder" could be called to account??? is the property covered under the NHBC [Spit Spit] at times worthless cover??

Ken.

 

[Bri44]

It is covered by LABC.
The developer was given 3 months to fix these back in Feb 2018. They were covered in the 2 year period. They hired a dodgy company Nov 2019 who made a pigs ear of the repairs. I complained and that’s where I am as of today.
They have not suggested a survey.
I did get a survey before these repairs were started and he replied back to me today saying mesh and get a guarantee.

I asked the render guy why the expansion joints stopped and he said because they hit the natural barrier, the sunken in windows and structure.

 

[Bri44]

Quick update.
The developer is saying its just movement cracks without having it inspected.
Yesterday the manager from the rendering company called round and explained they would mesh over the cracks before rendering and his expert renderer who was at the initial meeting would do the repairs. The developer had already sent out a cowboy company in Nov 2019 who messed it up and this company is supposed to be the specialist to repair the bodged repairs from the first attempt.
Two guys turn up, they speak very little English so hard to communicate.
I watch him start filling the area with render, no mesh applied.
I tell him he needs to mesh first. He says I did mesh. I say, you never as I just watched you. He says, ok I never but I will mesh the others. He says, my boss just tells me to come and render the cutouts.
He phones his boss and passes the phone to me. I try to explain no mesh. He does not let me speak. Shouts, F the developer, F you, don`t tell me how to do the work and hangs up.
Now waiting on the manager to turn up.
What a lovely company.

 

[KenGMac]

I would have thought that the "missing" section of expansion joint should have been cut out, with provisions made to install cross expansion joint wall ties with if needed [Structural Engineering input please] tying the two cut faces of the wall that has been [or not been] cut.

As for the lack of mesh? when the manager turns to ask him to prove to you that there is mesh in the repair? if needed, use a magnet ??? it will be held to the repair if there is mesh in there, unless the mesh is Stainless Steel.

Sounds like a really cheap jack bodge?

What guarantees, if any will you get?

Ken.

 

[dontbelieveawordofit]

they’ll most likely use plastic mesh specific to the render. and you’ll always see it , it’ll always look repaired.
you need an independent survey .
the whole elevation should be stripped to expose the expansion joint and cracked areas as stated .

 

[Bri44]

As it stands the render company said they can’t render until they know if these cracks are active and the cause. The developer is sending a structural engineer out next week.

The longest crack 18 Ft has two other 10 ft horizontal cracks that have been cut out.
You can see one in this picture and the other runs level with the next level scaffold board.