Help - Is my leaning dry stone barn wall dangerous?

[Mike'srenovation]

Hi, I have a barn in France that is built using traditional dry stone methods with rubble in the centre. Inside the barn, I have a dividing wall that is also dry stone but doesn't appear to be tied in to the externall walls. I wanted to point it with lime mortar but have found out that it leans by about 5cm each metre (I measured a 2 metre lenght with a plumb bob an it was 10cm out). The wall is made with pretty big and decent stone and about 50cm thick.

I think it's been like it for the twnety years we've had the property and, visually, it looks ok, but I'd like some advice to know if it needs to come down and be rebuilt. Any advice welcome.

Thanks,

 

[freddiemercurystwin]

Got a photo?

 

[RonnyRaygun]

Rule of thumb is that if a wall leans less than 1/3 of the thickness it's OK as it keeps the load within the middle third of the wall. Better still if it's restrained by floor joists or rafters.

So should be OK, but would be interesting to see some pics. Although that depends on the overall height

 

[Mike'srenovation]

Thanks Freddiemercurystwin and Ronnyraygun for your quick feedback and info. I've attached some pics that I hope helps make it a bit clearer. I used a strip of wood to hopefully illustrate the size of the lean. The stick is 2m and the distance from the wall at the top 10cm roughly.

The wall on the other side drops down another metre as we are on a slope so the floor is lower on the other side.

Any further insights would be very much approaciated.

 

[George_engineer]

Is it leaning or just getting narrower towards the top (common detail for drystone walling)?

 

[Mike'srenovation]

Unfortunately, it's leaning out on both sides, it's not a taper.

 

[conny]

Is it leaning towards the lower level floor?
Is the top of the other side of the wall further out, or less of a gap to the perpendicular base?
i.e. the top of the ones in your pics are roughly 10cm further in than the base. Is the top on the other side also 10cm in from the base or 10cm past the base?

 

[Mike'srenovation]

Hi Conny, Very good questions! If it's ok, I'll make a proper inspection tomorrow morning and measure up on boths sides. I'll then be able to draw up and attach a diagram to show what's moved where. Thanks,

 

[Mike'srenovation]

Hello everyone, sorry, it's taken longer to get back to you with the info that Conny asked for. I've had a few more issues to deal with including a leaking roof in the house. I've tried to illustrate the lean on my dry stone wall below. You will see that the floors either side of the wall are at different levels. On the barn side, it drops down a further 70cm before meeting a stone layer that is 40cm high above ground - not sure what purpose this has, but the previous owners used it as a kind of shelf for storing various garden pots, etc. The wall leans on both sides the same way, at about 10cm over a 2m drop from the top. The additional 70cm drop section on the barn side has a 5cm lean over the 70 cm. However, all these figures are approximate and vary depending upon where along the wall you measure. The question I have is, can I simply point the wall with lime mortar to stabalise it or do I have to take it down and rebuild it. There are big gaps so I can get quite a bit of mortar deep into the wall in a lot of places. It is an internal wall and has no load bearing properties. There is a roof A frame above it but this rests on the external walls. Again, any advice would be really appraciated. Thanks Mike.

 

[George_engineer]

Hmm... I think...

70cm below floor level
Backfill voids with stone and point with lime mortar
This is provide a solid base where the wall is experiencing lateral thrust.

Rest of the wall
Bbackfill the rest of the wall with stone only (maybe some hidden lime mortar but just to ensure it is tightly packed in)
This is to preserve the historic character and form but ensures the wall is sound as far as is possible.

Top of wall
Install hidden restraint fixing, or perhaps some timber beams along the top. Eithe attached to the roof or to the side walls.
This would be to restrain the top of the wall.

Monitor
Keep an eye on the wall by using an objective measure. For example, nails or a tell tale. Record the findings.
This is to check there is no ongoing movement.

 

[Mike'srenovation]

Apologies for the delayed response, I've been sidetracked by work events. Thanks very much for the useful guidence George, sounds like you think it can be saved rather than pulled down. I like the idea of a restarint ring and can be applied easily.

 

[Mike'srenovation]

Actaully, thanks again George, I've just fully comprehended your thoughts about the backfill. This also makes great sense and I've got enough stone from an old garden wall that will do the job. brilliant.