Wall ties

[beka]

Hi all,

Going thorugh our project planning for the renovation and trying to deiced whats necesary and whats a load of b******** based on surveyors reports etc.

We were told that we needed to insert lateral wall ties in between the outer walls and the party walls because there was some evidnece of splitting of wallpaper and gaps in skirting board at corners.

The building dates from 1846, the outer walls are solid stone, the party walls are solid brick inserted in victorian era when the mill was divided up into houses. There are no internal loadbearing walls just a beam from front wall to back on the ground floor and nothing on 1st and second floor.

Now from a bit of readign around I've done wall ties are for cavity walls, so I'm a little confused as to how you would put them into this house and also wodnering if they are needed? I guess my instinct is that if a house has stood for over 150 years with no huge cracks or bits falling off then its a pretty sound structure. On the other hand if the thing about wall ties is needed I want it done now whilst we are still at first fix stage of the renovation.

What should my next step be?

 

[Penners]

I reckon the first thing you need to consider is the length of time that this possible separation of the internal wall from the outer wall has been in existence. Does it look recent; is the split wallpaper fairly modern; does it look as though the skirting board corner joint has pulled apart recently (one test for this - is there paint on the separated faces - if so then the separation clearly happened before the most recent coat of paint was applied)?

If it all looks pretty old, then the separation might have happened soon after the internal wall was inserted, through settlement of the building, and everything may now be in equilibrium. That being the case, you may not need to do anything other than fill up the gap.

But if there is some recent movement, you would have to decide what's moving away from what. If it's the external wall that's moving outwards, then it's possible that you might need to put some sort of tie structure through the building, with a plate on the outside. I certainly don't think that the kind of wire wall ties used in cavity walls would be much use for a situation like this.

Bottom line - unless you're confident that you can diagnose the cause of this separation yourself, I suggest that you need the services of a structural engineer.

 

[DaveBrigg]

A lot will depend on whether the survey is tied to a mortgage of course, when the choice may not be yours. The first thing is to check what was meant by lateral wall ties. These could be long ones, that are fitted between the two outside walls to stop them spreading any further apart (under the weight of the roof) There are some pictures and a brief explanation just over halfway down this page http://www.dhdstructural.com/services.htm
Or, you might be able to get away with lateral restraint ties, such as those here http://www.vistaeng.co.uk/04_lrt.html which tie the external wall to the internal dividing wall. If the front of the building really is still moving, they will probably not be good enough. As well as Penners advice above about checking to see if the movement is historic, it would be worth speaking to other property owners in the building, or at least looking for evidence of earlier wall ties. Are there any metal plates on the front of the building, or bits of ironwork in an S shape or similar? If there is movement in the walls, it is unlikely to be just your property that is affected. Mnay old buildings bow slightly at the front or back (or both) but it takes a structural engineer to decide whether this is an acceptable amount or not.

 

[chuckey]

I would wait a whole year before doing anything. The reason being that as the brickwall could be standing on its own foundations (not tied into the main structure) what you could be seeing is heave and/or subsidense. i.e. the party wall is going up and down w.r.t the main structure depending on the moisture content of the soil. My friends house suffered from this, his wallpaper wrinkled at the internal corners. Is there any sign of wrinkling( angular folds) or is it a straight pull apart scenario?
Went an old mill once that had side to side ties, inside you could see they were 3/4" concrete re-inforcing rods for the main part of their length welded together with 1" studding welded on their ends. V cheap!! Could cost a bit to have the bossed "X" s made.
Frank

 

[Edwardia]

The surveyor's report done for the bank on our Edwardian mid terrace mentioned that the wall ties should be replaced. The estate agent told us that this was always recommended on any pre WW2 house, so maybe your surveyor saw some signs of movement and was covering himself ?