Wall Tie Replacement

[freddiemercurystwin]

Wall tie replacement can indeed mean exactly that depending on the severity of the corrosion. There are several methods of isolating the old wall ties including sleeving, bending and cutting if necessary. The BRE have carried out extensive research in to this problem and no one can deny there are plenty of dubious installers out there who just want your dosh. Despite this and what you seem to think whilst no one on here is suggesting his wall is very likely to fall down there is a possibility, especially as you really don't have any real idea of the extent of corrosion yourself. Are you suggesting that surveyors or structural engineers receive a fee from the wall tie replacement federation every time they condemn existing ties in a property?

 

[joe-90]

Well what do you think? Are you saying that DPC installers didn't operate the same way? Outer leaf failure is very rare and usually happens in areas of very high winds. Gravity and friction is what holds a wall up - not wall ties.

If the wall aint bowing - it aint worth doing.

Oh and by the way, slipping slates on a roof is a sign of nail corrosion. That means just about every house from the same era needs a new roof.

 

[freddiemercurystwin]

I've already said what he could do, as well as speaking to building control he can ask them to recommend a good structural engineer for another opinion. I've also suggested that he shouldn't take the word of someone off a forum especially one who is categorically saying it'll be fine. A slate slipping off a roof is unlikely to cause the same catastrophic result that a wall collapse could. Do you know if he lives in a windy/exposed site or the extent of the corrosion ? No, you do not. By his brief description it doesn't sound that major anyway. I suppose its ironic that with your extensive 30 years of experience you could have built cavity walls yourself with wall ties that are now failing!

 

[joe-90]

I've already said what he could do, as well as speaking to building control he can ask them to recommend a good structural engineer for another opinion. I've also suggested that he shouldn't take the word of someone off a forum especially one who is categorically saying it'll be fine. A slate slipping off a roof is unlikely to cause the same catastrophic result that a wall collapse could. Do you know if he lives in a windy/exposed site or the extent of the corrosion ? No, you do not. By his brief description it doesn't sound that major anyway. I suppose its ironic that with your extensive 30 years of experience you could have built cavity walls yourself with wall ties that are now failing!

Walls don't just collapse. Friction and gravity ensure that much.

If he employs a structural engineer he will recommend that the ties be replaced just to cover his own ass to prevent possible legal action at a later date. If he gets an opinion from a company that replaces ties they will say replace them to get the work. It's just money down the pan. It's a self-fulfilling prophecy.

 

[freddiemercurystwin]

I suppose you're right, I dont know why they bother installing wall ties in new construction to be honest, or even bother with a cavity. Damn those pesky building regs again!

 

[^woody^]

Outer leaf failure is not the main problem.

The main loads are on the inner leaf, so this will be pushed outwards from the load of the roof and possibly floors.

As the internal wall will effectively be a single 100mm leaf at 5m high, it will not resist the spread of the roof.

So whilst it may not actually be pushed over, it can rotate from vertical, causing the roof and/or floor timbers to deflect and sag. So you get more problems.

There are other issues too, and it is not about the walls falling, but how those walls are dealing with the loads on them.

To avoid the problem, and/or mask the problem to get a sale would be negligent - especially in the course of a business.

 

[joe-90]

The weight of the house is directed down into the foundations. If the inner leaf sags then the house would need underpinning. This has nothing to do with wall ties. In fact if the inner leaf were to sag then the wall ties would pull the outer leaf down with it causing even more problems. Also rafters have cross bracing and joists which effectively reduce spread to zero. All the weght of the roof is directed down into the foundations. One leaf of brick/block can easilly cope with this weight.

 

[daverik]

All in all, wall ties are necessary. If they need replacing then it should be done. They are there for a reason and if they are not performing there reason for existence then that is it.

Load spreads at 45 degrees so the weight is spread throughout the structure.

 

[^woody^]

The weight of the house is directed down into the foundations. If the inner leaf sags ..... Also rafters have cross bracing and joists which effectively reduce spread to zero. All the weght of the roof is directed down into the foundations. One leaf of brick/block can easilly cope with this weight.

Its not about the wall sagging (who mentioned that?), it is about lateral forces (sideways) acting on the wall, and rotation from the vertical axis.

Bracing in the roof braces the roof timbers together. The rafters and joists still exert a force, which will try and push the walls sideways.

Your opinion seems to be contrary to all technical reports, guidance and investigation into this problem from all the industry bodies.

It also contradicts accepted building practice and regulation in relation to the requirement for cavity ties to actually be used in the first place.

I accept that everyone else may be wrong, but untill some reasoning other than "it's a scam" is provided, I think it may be wise to go with the mainstream on this issue.

I don't suppose the commercial aspects of renovating properties for a living [profit] has anything to do with your judgement in getting certain work done, does it?

 

[anobium]

Joe , I take it that from your comments that when you build a cavity wall, you don't use cavity ties.
Well do you or don't you?

 

[noseall]

stop digging holes joe.

please, it's embarrassing.

 

[noseall]

i would be wary of any company that does remedial work that the customer cannot see, or outwardly benefit from, these said works.

these unseen works are what make it attractive for shysters and fraudsters to make a quick buck out of the unsuspecting.

all that said, it doesn't detract from the fact that there are genuine cases of wall tie failure and genuine wall tie remedial companies.

 

[joe-90]

The weight of the house is directed down into the foundations. If the inner leaf sags ..... Also rafters have cross bracing and joists which effectively reduce spread to zero. All the weght of the roof is directed down into the foundations. One leaf of brick/block can easilly cope with this weight.

Its not about the wall sagging (who mentioned that?), it is about lateral forces (sideways) acting on the wall, and rotation from the vertical axis.

Bracing in the roof braces the roof timbers together. The rafters and joists still exert a force, which will try and push the walls sideways.

I think you must live in an alternative reality where the rules of physics aren't the same as ours.

The whole principle of building is to put the weight of the building into the foundations. It's always been that way. At least after the Normans who didn't quite realise it.

Can you tell me where the lateral forces are that are pushing the walls over? The fact is that you can remove all the mortar from a house but it won't fall down. The reason for that is that all the forces are downward. That's why we have joist bearers and purlins. These put the weight of the roof into the walls and down into the foundations. It's pretty basic stuff.

Can you tell me how an inner leaf of a cavity wall can sink in realation to the outer leaf without complete faliure of the foundations?

 

[joe-90]

stop digging holes joe.

please, it's embarrassing.

Maybe you'd like to join me in a technical debate - if you dare.

 

[joe-90]

Joe , I take it that from your comments that when you build a cavity wall, you don't use cavity ties.
Well do you or don't you?

Stainless steel ties.