wall deflecting inward where chimney breast removed

[davidm1969]

Hi all, am looking at buying a property built c 1900-1910 where some courses of bricks next to a former chimney breast appear to be deflecting inward. Survey [level 3] says

"To the rear wall, there is evidence that makes us consider that there was a chimney stack, which has been removed and there is a lead weather detail in place to cover the protruding chimney breast, which remains. It does appear that the chimney breast wall is inwardly deflecting off vertical to the upper brick courses. This wall, as it is no longer supporting a chimney breast, requires stabilising, by way of removing the deflecting brick courses and rebuilding that upper section of wall back to vertical, which is both structurally sound

For a building contractor to remove the deflecting brick courses to the rear projection wall and rebuild to verticality. This may involve some form of helifix wall ties embedded in the mortar courses to stabilise this wall. We estimate the cost of this repair to be around £1,500 Plus VAT. (See photo A)"

Originally the surveyor was saying it needed a structural engineer to take a look, but now, after looking further and considering there is no longer a chimney above supported by this wall, he is saying making good the affected courses will suffice.

Photos attached.

Please can you the experts here let me know whether they think the surveyor's new view and proposed solution is right, whether this actually does need fixing [as it must be only a slight deflection I think], if you think it could be something else. My only other thoughts are it could be poor original workmanship, it could be the pointing on the bricks in the corner of the building at the top have failed [as exposed the most], or it could be something to do with the roof structure supported by the wall [maybe more of the load goes into the corners if something has failed in the roof structure?] but you all know more about walls than me

as ever thanks very much for all contributions, it's very much appreciated

best

David

 

[^woody^]

A wall bowing is not a problem and does not need any rectification unless an actual problem has been identified.

If your surveyor has not identified a problem then he's not done his job. Further, he would need to explain what why the wall needs rebuilding if he is now advising it to be rebuilt.

 

[davidm1969]

Hi Woody

Thanks for that I think the rationale was walls are meant to be vertical structurally and aesthetically he only means the top few courses

The wall will be supporting the roof structure I guess. So at the least I 'think' it needs looking at close up to see if the pointing/mortar there is still ok and that it will continue to do that ok. I can see at least that it needs looking at.

Any ideas why it would be bending inward/what's causing the problem ?

Best

 

[^woody^]

It's difficult to see what's going on from the images, but typically if there is a bow in a wall where there is a flue within, then its most likely sulphates from the flue gas.

These react with the cement in mortar from ongoing rain soaking into the wall and soften the joints, causing the wall to bow under its own weight.

If this is occurring then it will need dealing with as it only gets worse. In addition, the extent of the compromised mortar needs to be determined , as new areas can be affected by ongoing rain later.

There may be other reasons, such as some past movement or poorly bonded bricks with the chimney, but it's important to diagnose properly first, as past movement can be left as it is, but if its ongoing movement then the cause needs to be determined and dealt with before just rectifying the wall.

If it is sulphates, then a special cement is needed when rebuilding.

In context, this issue should not put you off the property. But you need to know the risk and commitment, and if need be get a reduction in the asking price.

Refer back to your surveyor and ask his opinion on sulphate attack from the flue.

Also ask about the actual cause, eg if movement from the roof timbers (roof spread) is suspected.

You may need a structural engineer's comment, and schedule of repair. What ever you do don't just get a builders quote to rebuild, or let a builder just crack on.

Above all, don't just instruct a repair unless you know the actual cause, and deal with that first if need be.