Wall Stability

Yorky1 said:

Is it safe?

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Safe as, err ....... houses

No NHBC cover in Ireland - Homebond instead. The house is 2.5 years old.

Shytalkz said:

^woody^ said:

I haven't got a clue, but I do recall an afternoon in my structures lessons - something to do with imagining an archway but horizontal and compression, transfer of loads, being stonger under load etc etc. No need to bore you with it

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Lol, you b****y chancer . An afternoon? Your entire structures lessons were an afternoon. Tops!

Parallel axis theorem ol' boy: it's to do with the respective inertias (resistance to rotation about the axis of mass of a body in that direction in space): looking on plan, a crinkle-crankle or circular wall has a greater inertia than a straight wall of equal thickness, by virtue of their respective extremities being further away from their neutral axes of the whole than that of a straight one.

For rectangles, I = bd^3/12 + AH^2 for each element of the body. That's why a ruler is easy to bend when held flat, not so easy when you turn it on edge.

And that is why SEs should deal with structural matters, not surveyors

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Bloody smart arse! Don't forget that this is a DIY forum

...so anyway, this 'No More Nails', is it any good, and can I use it in conjunction with party streamers to make my own flypaper?

Deluks said:

b****y smart a**e!

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No, just someone who's had more than an afternoon's training in structural mechanics . So many things in building are taken as a given, with no idea or consideration as to why or how they work. Or don't work, as the case may be...

Deluks said:

Don't forget that this is a DIY forum

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And so it is; and that was a quick reprise for Woody, to make up for all those lectures he obviously missed. He can probably get a couple of hours' worth of CPD on the back of that

Hehe, I missed few lessons and to make up for those I did, I just blag my way through.

Seriously though, I like to break everything down to easy terms, with context and what things mean in practice.

Frankly, the science and the maths bore me, and my view is that the replies should be easy to read, and if the reader wants to delve further, then it gives them the basics for an evenings googling.

This wall is strong because its like an arch - now think of an arch holding up a bridge and thats pretty strong. Now does that sound better than if I had quoted advanced arch theorem?

I'm struggling with your arch analogy though...ok if the wind was blowing from the crown side then yes it could be - sort of - viewed as acting like an arch (as long as it's adequately buttressed, otherwise it spreads out), but equally so could a straight wall, which would effectively be a flat arch on that basis. And, what about when the wind's blowing the other way? Loads on arches don't go upwards and they wouldn't work if by some quirk of nature they actually did so, but that is what that analogy is effectively saying. Meantime the straight wall, would work in exactly the same manner which ever side it was loaded on, so the analogy would then suggest that it's possibly stronger than a curved wall!

Simplicity is fine, as long as it simplifies it correctly .

But, in the main, mate, your posts are erudite and very practical, pragmatic responses, you just lose your way on structural bits sometimes (like 99.99% of chartered building surveyors!)