What causes a wall to bow?

[indus]

Hi

Could anybody shed some light on what causes a wall to bow and how you fix it?

The property below has some bowing walls. You can just see it between the two upper windows.

Many thanks

 

[RonnyRaygun]

Usually walls bow when they are tall and not tied in sufficiently to a floor, or often where there is no floor at all such as adjacent to the stairwell.

Where the above is the case the wall is too slender to be stable against buckling about its weak axis and will often start to bow over a period of time.

If there is a floor adjacent the wall can be restrained by using remedial ties into the joists. If it is bowing near a stairwell it is more difficult to resolve, but it may be possible to span some steel between points of restraint and restrain the wall to the steel.

In the case above it looks like the property has already been remedially restrained at some point in the past, with ties either side of the doorway that probably go from one side of the building to the other between the joists.

The bowing between the two windows could be caused because it's a small panel of brickwork carrying quite a large load.

 

[indus]

Thanks Ronny.

Can you actually see evidence of remedial ties from the photos?

 

[RonnyRaygun]

Thanks Ronny.

Can you actually see evidence of remedial ties from the photos?

Yes, the big "S" shaped patress plates are the remedial restraints. They are a traditional method of restraint, although these days you can get modern systems that go directly into the joist ends or through the joists such as that marketed by Helifix.

 

[indus]

Thanks Ronny, well spotted!

If you wanted the best end result ie a perfect aesthetic and structural stability and were happy to gut the place what would you do?

Many thanks

 

[RonnyRaygun]

Thanks Ronny, well spotted!

If you wanted the best end result ie a perfect aesthetic and structural stability and were happy to gut the place what would you do?

Many thanks

I'm guessing that the stairs run adjacent to the wall, based on the positions of the windows and the fact the wall is bowing.

If so, you could move the stairs somewhere else giving you opportunity to restrain the wall by fixing into the new joists. Of course, that may just move the problem somewhere else, so maybe the stairs could run centrally in the building between new stud walls.

Everything has a price though, so it depends on how much you want to spend. If money is no object the wall could be rebuilt.

 

[indus]

Thanks Ronny. You are correct it is the wall with the stairs. The problem is the wall opposite it is also bowing and I also think the rear wall is doing the same!

The roof needs replacing anyway so I wonder whether the solution is to to rebuild the whole of the first floor??.

 

[RonnyRaygun]

The roof needs replacing anyway so I wonder whether the solution is to to rebuild the whole of the first floor??.

I would think that would be excessive unless the bowing is extremely severe.

You would still have to restrain the new wall to stop it from bowing anyway.

 

[indus]

Thanks Ronny.

The bowing is very very evident to the naked eye and so I'm assuming Joe Public would walk away from it come resale time?

Also you say the new wall would have to be restrained to prevent rebowing? Wouldn't the new wall be built using modern practices that would prevent this?

Thanks again.

 

[RonnyRaygun]

Hi Indus,

I don't think people would necessarily be put off by a bow in the wall as long as it has been dealt with an restrained properly. Have you checked the actual bow in the wall? Has anyone dropped a plumb line down the wall and measured it?

If the wall was rebuilt it should be designed to prevent it bowing, and engineer's input would be required.

Your best option might be to get an engineer to survey it and report on a solution.