sorting "spread" walls in an old building
Discussion
we've got some land with an old outbuilding (it used to be a stables). Its single story, about 6m x 3m, with a simple pitched roof. The walls are a single skin of 2-wide bricks. The roof's got clay tiles, and its around 100 years old. The pitched roof currently has a collar tie towards each end, but no rafter ties.
on one of the long walls there's 2 windows - I don't know if they're original or were cut in afterwards - but they run all the way to the top of the wall with either no lintel, or a simple wooden lintel (hard to get in there to see). As a result the middle section of wall between them (approx 1.6m wide) has no lateral support.
The middle bit of this wall has spread outwards dramatically - I'd say 3 or 4", maybe a little more. The end sections of wall are relatively square, so the windows are effectively taking up the slack and sit a bit diagonally. There are cracks in the brickwork roughly in line with the windowsills - so it looks like the brickwork is mostly still good, but its all just canted over at a bit of an angle.
Reading up, it seems like I can stabilise the roof with some rafter ties, - this seems like a fairly simple job that I can get sorted this week - but my question is whether I should be trying to "correct" the sag before I do this - either by somehow jacking up the ridgeline, or ratcheting the two sides of either the walls or opposite rafters together, until it is "square", then adding the ties in, so they're be under more tension but the building would be square again? I don't really mind about the astetics of the wonkyness, more the structural stability of the building as a whole. Or if I don't do that, do I need to repair the cracks in the walls with anything? The building is tucked away in some woods, so isn't really exposed to any strong winds, just gets rained on a bit.
on one of the long walls there's 2 windows - I don't know if they're original or were cut in afterwards - but they run all the way to the top of the wall with either no lintel, or a simple wooden lintel (hard to get in there to see). As a result the middle section of wall between them (approx 1.6m wide) has no lateral support.
The middle bit of this wall has spread outwards dramatically - I'd say 3 or 4", maybe a little more. The end sections of wall are relatively square, so the windows are effectively taking up the slack and sit a bit diagonally. There are cracks in the brickwork roughly in line with the windowsills - so it looks like the brickwork is mostly still good, but its all just canted over at a bit of an angle.
Reading up, it seems like I can stabilise the roof with some rafter ties, - this seems like a fairly simple job that I can get sorted this week - but my question is whether I should be trying to "correct" the sag before I do this - either by somehow jacking up the ridgeline, or ratcheting the two sides of either the walls or opposite rafters together, until it is "square", then adding the ties in, so they're be under more tension but the building would be square again? I don't really mind about the astetics of the wonkyness, more the structural stability of the building as a whole. Or if I don't do that, do I need to repair the cracks in the walls with anything? The building is tucked away in some woods, so isn't really exposed to any strong winds, just gets rained on a bit.
Lotobear said:
Unless the out of plumb is severe I would leave as is and simply introduce ties to alleviate any further thrust.
...you could do a simple middle third asessment of the walls if you wanted to apply some 'method' to your approach.
@Lotobear - if I'm doing the middle third assessment would I include the load from the roof (in which case I'm fairly sure its fine once the rafter ties are in) or just the wall as if the roof is taken off (in which case, I'm probably within the 1/3rd when taking into account the whole height of the wall, but outside of it when taking into account only the bit above the cracks)....you could do a simple middle third asessment of the walls if you wanted to apply some 'method' to your approach.
5lab said:
Lotobear said:
Unless the out of plumb is severe I would leave as is and simply introduce ties to alleviate any further thrust.
...you could do a simple middle third asessment of the walls if you wanted to apply some 'method' to your approach.
@Lotobear - if I'm doing the middle third assessment would I include the load from the roof (in which case I'm fairly sure its fine once the rafter ties are in) or just the wall as if the roof is taken off (in which case, I'm probably within the 1/3rd when taking into account the whole height of the wall, but outside of it when taking into account only the bit above the cracks)....you could do a simple middle third asessment of the walls if you wanted to apply some 'method' to your approach.
If it were me, given the wall has not failed in the existing unrestrained condition, and that you are going to address the lack of restriant by introducing ties I would take a practical view and leave the walls as they are unless you wanted to realign them for aesthetic reasons.
I'm sure a structural engineer will be along at some point to provide a more considered view.
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