Gable lean maths question
Discussion
I have an old french house and the gable wall, both sides, above first floor leans about 150mm over 2m according to spirit level. What degree is that. There is no sign of movement and the house is 400yrs old so I assume it was built like that. the walls are around 700mm thick and solid random stone.
Strangely the first two floor walls are fairly vertical. They lean the same way as well, one toward the house and the other away. I'm thinking I might need to install some pattress plates.
Strangely the first two floor walls are fairly vertical. They lean the same way as well, one toward the house and the other away. I'm thinking I might need to install some pattress plates.
Equus said:
The answer is Shuff4's 4.3 degrees, near as makes no difference (4.289, to be precise, if the dimensions given were absolutely spot on).
The very rough rule of thumb is that if an imaginary vertical plumbline from the top centre of the wall stays within the middle third of the thickness, its fine.
A quick fag-packet calculation suggests that on a wall thickness of 700mm, that amount of lean would be fine up to about 3.11m. of wall height.
If in doubt, consult a structural engineer, of course: there can be other factors involved.
Slightly depressing that we're sending people out from our schools these days who not only can't do basic Trig, but don't have the wits to look up a calculator to do it for them on Google.
We didn't learn that type of thing in the 'schools' we went to. I left in 1979.The very rough rule of thumb is that if an imaginary vertical plumbline from the top centre of the wall stays within the middle third of the thickness, its fine.
A quick fag-packet calculation suggests that on a wall thickness of 700mm, that amount of lean would be fine up to about 3.11m. of wall height.
If in doubt, consult a structural engineer, of course: there can be other factors involved.
Slightly depressing that we're sending people out from our schools these days who not only can't do basic Trig, but don't have the wits to look up a calculator to do it for them on Google.
Edited by Wayne E Edge on Thursday 22 August 18:38
Equus said:
If it's built with lime mortar, then the mortar is slightly 'plastic' and can 'flow' or deform to some degree before failing (see 4th paragraph, page 11 of this document). It almost certainly wasn't built like that - even 15th Century French cowboys weren't that bad - so you do need to be conscious of the potential for further movement.
Thanks for all your answers. Tje stone is held together with clay Edited by Equus on Thursday 22 August 10:37
Equus said:
Again (and unlike cement mortar) clay has a degree of plasticity and can 'creep' over the years.
It will continue to move, but if it;s only got that far in 400 years, you probably don't need to worry too much in your lifetime.
LIt will continue to move, but if it;s only got that far in 400 years, you probably don't need to worry too much in your lifetime.
Think I would remember that. No rhymes in our school.
Edited by Wayne E Edge on Sunday 25th August 21:04
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