Split sandstone repair

[T42]

The lower hinge of one of our barn doors has split the sandstone block it's anchored in.




The door is about 4.50 metres tall, and although it's just pine it's heavy enough.



The top hinge is into oak and AFAICS takes all the weight. Forces on the lower hinge are mostly lateral. Just now it's not moving in the stone, and the door will still swing without it shifting.  There was a bit of wood driven in alongside it, which has probably helped things along.

I did pick up a Cyanolit mastic with a nominal bonding strength of 200 kg/10 cm², but while that might suffice for a cosmetic repair I haven't much confidence in its holding against the forces on the hinge.  I'm thinking that a two-part epoxy would be better.

What thinketh the panel?

[mrcharly-YHT]

Big FO bolts, above and below the hinge pin, all the way through, with a large washer to spread the load.

[T42]

Those resin-anchored ones?

I'm rather worried that the shock of percussion drilling might shatter the rest of the block.

[rafletcher]

Aunt M probably knows better than most what a good solution would be. FWIW I think sandstone is generally soft enough that you either don’t need to use a hammer drill, or can use it with light pressure.

[T42]

Your mouth to God's drill-bit.  I was also thinking of putting iron strapping round it.

[mrcharly-YHT]

You could strap it - but it would be difficult to get enough pressure to stop the crack from opening and the pin from working loose.

When I say 'bolt', it would probably be threaded rod with a nut on each end.

If it is sandstone, I think rafletcher is right, just go slow, no hammer and you'd get through. Keep clearing the waste.

Is the crack running across the corner or all the way through? I can't tell for certain from your photos.

If it is the corner then maybe combination of a strap and one bolt.

Epoxy isn't going to do anything - it will just bond to the surface of the stone and there is no tensile strength to speak of in stone.

[T42]

I can't tell if the crack in the top pic runs all the way front to back. I'll get another pic with the door open once the wind takes a tea-break.

[Aunt Maud]

Your mouth to God's drill-bit.  I was also thinking of putting iron strapping round it.

That's probably the best solution, get the straps made by a decent blacksmith if you can. Or replace the sandstone piece with a new one, which should be easy enough to do.

[Aunt Maud]

Super barn T42, any more photos?

[T42]

Ta! I'll see if I can dig some out. It's a bit dilapidated now, after various storms & obstreperous trees had a go at it, but fixing it would cost a mint.

Here's one from 2005:



It's around 23 metres long.

Re the block of sandstone, it's around 110x40x40 - probably the biggest block in barn or house.

[Aunt Maud]

You should organise a YACF "fix my old pile up in the traditional way" week, you might find that saving it wouldn't cost that much in the end.

[Canardly]

If a new gudgeon is to be let into a new piece of stone should it not be set into molten lead? Or possibly right through if purpose made? That is some barn.

[Legs]

Your mouth to God's drill-bit.  I was also thinking of putting iron strapping round it.

That's probably the best solution, get the straps made by a decent blacksmith if you can. Or replace the sandstone piece with a new one, which should be easy enough to do.

Would turning the stone around be a workable solution?

[Canardly]

Could the gudgeon be dispensed with altogether and a floor mounted rotating pin set in concrete be used? The stonework could then be patched using a stone fleur and Akemi with  the band left in situ for visual effect.

[T42]

The stone is big - 110x40x40 at least - and load-bearing, and the pillar it's part of also forms the left side of my workshop's doorway. I'm not worried about the barn staying unlocked but the workshop has too many goodies inside. In other words, the stone can't be moved without a hell of a lot of faff.

I'm leaning towards filling it up with concrete and using bolts and strapping to keep it together. Alternatively, using the Cyanolit mastic to cement the bits together while I get the strapping on.  I'm not worried about it looking nice, I just need it to hang together for another 20 years and then it'll be someone else's problem.

[Aunt Maud]

Iron straps are a common form of historic repair for stone and timber. I've seen examples of temporary timber repairs using strakes from cart wheels which are 400 years old. I have one above the door in the house.

I'd advise against using concrete or cement based products, as they can cause serious frost damage to stone. You could use pure lime as a filler for the original piece and stick it back on with a strap all the way around the piece of stone, which incorporates a new pin for the hinge.

[T42]

Interesting re the cement - thanks. In my second pic, on top of the chunk of stone lying on the floor you can see the remains of a bit of wood someone drove in 30 or 40 years ago, presumably because the hinge was loose.  I reckon it has acted as a wick to draw in moisture that did the damage.

I had also thought of drilling through the tab of the hinge and putting in a resin-seated bolt to stop it waggling.

[Aunt Maud]

Or expansion due to rust on the hinge.

[LittleWheelsandBig]

That is likely but wetting and drying cycles does the damage. Perpetually wet, not so much.

[T42]

Anyway, I've located a place near here that wreaks iron so I'll get them to make me a couple of wrap-around straps next week. Might as well get them to rust-proof them as well.