Somewhat OT: Scottish Schools

[mark.bluemel]

Did I miss the announcement of an embargo on wall-tie supplies north of the border?

[spuorgelgoog]

No, it's a requirement for local style for bits of masonry to fall off buildings in Edinburgh.

That or the customary excellence in project management, Parliament, Trams, qv.

Owain

[Brian Gaff]

I'm still not sure what exactly the structural problems actually are. They are all talking about errors being made but nobody seems to have said exactly what the issue was. Bricks falling out of outside walls could be due to poor maintenance after all. Brian

[damduck-egg]

Being stockpiled to build a new wall along it, hopefully.

G.Harman

[Andy Burns]

The one I saw on the news showed the outer brick leaf of a two storey wall had collapsed in strong winds, revealing the insulation and lintels with no wire ties to the inner concrete block leaf.

On a building under 10 years old?

[Nightjar]

Something seems to be sticking out of the insulation, at regular intervals. It could be that there were simply not enough ties to resist the pull of the low pressure zone that can be created by a strong wind blowing around a corner.

[F]

On 12/04/2016 11:36, Nightjar Something seems to be sticking out of the insulation, at regular

I didn't get a good look on the news but I thought they were the clips used to hold the insulation to the inner leaf.

[Nightjar]

I agree that the pictures are not very clear, but to me they seem to be sticking out further than that.

[Andy Burns]

I noticed those and viewed the image at the max resolution, they seemed to be for holding the insulation to the inner leaf ..

Perhaps.

[Capitol]

Last time I saw this was a wall in PLymouth where the wall ties had rusted due to the salt atmosphere.

[charles]

PFI - says it all.

[Nightjar]

Given that the checks on the other buildings appear to involve digging holes in the walls at regular intervals, something along those lines seems likely.

[Andrew Gabriel]

No one has yet suggested it in this case, but 10-20 years ago, there was also a trend to economise on the amount of cement in the mortar in some housing estates, and that has a similar effect in that the wall ties even if present don't grip sand very well.

[harry]

They were retro fitting wall ties. Long drills through the outer leaf into the inner one.

[harry]

Error down to the bricklayers/bad supervision. Probably and early Polish brickie job.

[charles]

Edinburgh has had a significant Polish community since the end of WW2.

[Capitol]

I was surprised to learn that stainless wall ties can also corrode if the correct grade is not used in a salty environment. Apparently lime mortars produce less corrosion on galvanised wa;; ties, so there is something to be said for the traditional sand/lime/cement

6:1:1 mix.

[Nightjar]

Which is what I did to my house when the wall ties started to corrode inside the outer leaf. Mind you, mine had lasted over 70 years before that happened.

[Nightjar]

On 13/04/2016 10:01, Capitol wrote: ...

Even if you use marine grade, stainless steel can rust if it doesn't get enough oxygen to the surface to form its protective coating. Back in the

1970s, there was a spate of yacht keels falling off when their stainless steel bolts rusted in a salty, oxygen poor environment.

[charles]

Edinburgh doesn't have aprticularly salty air, except very near the sea when there can be spray duing storms. I can remember a major power failure in my youth when the spray shorted out the swichgear at Portobello Power Station.