pinning a bowing wall

[DanDIY]

Ive an outside wall that has a slight bow. I was concerned that it could be subsidence, but had a structural engineer round and he confirmed it was just bowing out and not really much to worry about.

The joists run in perpendicular to the wall. He suggested that for piece of mind I strap the first floor joists at both ends so that they act as ties across the structure and stop any further bowing.

Its a victorian terrace, so 9" solid brick, The leaning wall is in the kitchen in the side return area. So one end of the joists are in the party wall and the leaning side is the outer wall.

I was so relieved when the engineer said that it wasnt falling over I forgot to ask him what to use. Because it was only for 'piece of mind' he didnt spec anything out and also hasnt charged me!

For the metalwork to strap the joist to the wall would something like this be ok:

http://www.toolstation.com/shop/Con...me+Movement+Tie+200+x+50mm/d210/sd2797/p95575

or

http://www.toolstation.com/shop/Con...Angle+Plate+60+x+60+x+40mm/d210/sd2797/p98602

or using strapping bent into a U between joists

http://www.toolstation.com/shop/Con...Flat+Strap+30+x+25+x+300mm/d210/sd2797/p50060


For fixings, I do not know if it would be best to use a resin stystem, or anchor bolts, or even coach bolts with large rawl plugs. In theory, if the wall continues to bow, there could be some pull out load on these, rather than just the shear load that normal joist hangers would have.

Has anyone done anything like this before, can they advise?

Dan

 

[Joe Malone]

Dan, the first strap you have linked might be ok but I think you might misunderstand the principle. I am not a structural engineer, I am a building surveyor but the general principle is to fit an external wall plate to spread the load across the brickwork. The tie rod goes through the wall and can be connected to the wall straps. With a bowed wall I would be concerned that internal wall straps would provide adequate support because the load is not being spread.


http://www.extensionsandconversionsintaunton.co.uk/images/conversions13.jpg

 

[DanDIY]

Hi Joe, thanks for your reply.

I can picture what you mean about wall plates - the things you see on old cottages etc. From my conversation with the structural engineer that was not the kind of thing that he seemed to be talking about. If it were that kind of arrangement, then as I understand it, they go right through the building from one external wall to the other, so in my situation would need to go straight through the neighbors property and then have a wall plate on both sides. The engineer said it was a fairly simple job that I could do myself with off the shelf stuff......

I think the reason that you have the external plates on cottages is that the wall construction can vary - for instance it can be two leafs of stone with a rubble infill. In my 9" brick I have headers, so I think by attaching to the inner leaf only I should effectively be bonding to the whole wall.

I think if no one has come across anything similar I may contact him again to specify something, even if it means crossing his palm with silver.

 

[DanDIY]

A bit of an update on this. I was on google and found this google book result which explains exactly my issue. Ive posted a screenshot, hopefully if I reference it and it is freely available on google then this isnt a copyright issue.

Structure - Dearborn real estate. (from google books)

The fix in the book doesnt seem to be exactly what my engineer suggested, although the book is american, so it is likely that they have different solutions. But the diagram outlines the problem exactly.

I also found this old thread with a bloke with the same problem. Intrestingly he is also in Leicester. Maybe this is a local solution restricted to the Leicester area...

//www.diynot.com/forums/viewtopic.php?t=279135

 

[theprinceofdarkness]

I had an Edwardian terraced cottage, when we pierced the rear wall to open up into a rear extension, we discovered that the two brick skins had a 1" cavity where the inner and outer skins had somehow parted. - Never noticed that before. I suggest that you carefully survey the verticality of the inner wall, could be that just the outer skin has gone walkies. Also look at the straightness of the wall along the edge of the floor boards. The wall starts and finishes in the right place, if it has bulged it will not be parallel to the floor boards, but run away from them in the centre of the bulge.
Frank

 

[DanDIY]

The wall has headers, so that is not the case in my situation, but thanks for your suggestion.

The problem was noticed because the ceiling plaster was pulling away from the inner skin of the the wall at the edge. It wasnt a lot, maybe 15mm over the course of 100 years. But as I am having a new ceiling I dont want it to crack again after a couple of years.