Breakaway Stone Wall?

WriteMinded · Apr 3, 2011

Is it possible to weaken a (medieval) stone (and mortar) wall enough that someone could break it by leaning on it? Definitely by kicking it?

My question is about how this might be done. Atop a castle tower, a stone wall gives way, letting my MC's best friend fall. The structure was deliberately weakened in an attempt to kill the MC. - OR maybe it wasn't, if this can't be done - but I'm hoping it can.

mcamp · Apr 3, 2011

stone and mortar

hi, yeah, the top of many of the old fortresses were much narrower than the bases and it could be conceivable, given enough time, that someone could remove enough of the mortar holding this stone work together to make it very weak, but I think they culprit would also have to remove a small portion of stone, or maybe one block from the outside of the wall, that would be key and they would have to know exactly where the person was going to lean or kick the wall to make it work. So it all sounds kind of complicated to me... but doable...

WriteMinded · Apr 3, 2011

mcamp said:
hi, yeah, the top of many of the old fortresses were much narrower than the bases and it could be conceivable, given enough time, that someone could remove enough of the mortar holding this stone work together to make it very weak, but I think they culprit would also have to remove a small portion of stone, or maybe one block from the outside of the wall, that would be key and they would have to know exactly where the person was going to lean or kick the wall to make it work. So it all sounds kind of complicated to me... but doable...

Thanks! That was very helpful. My MC, not a big man, leans against the same place almost every evening. His friend, a huge guy, joins him one night and while they are talking he moves into the MC's usual spot, puts his back against the wall and, when he laughs, kicks the wall a couple of times. It breaks out. I thought the look-out, who the MC sends away whenever he goes up there, could be the guy who weakens the stonework. What could he use for a tool to work away the mortar? Would a knife do, or would he need something else?

Nick Blaze · Apr 3, 2011

Age is the most common way to have such a thing collapse. Castle walls were thick and I doubt a knife could make its way through the mortar. Of course, you are attacking the mortar, not the bricks themselves, right?

Stone walls are heavy. Removing a stone from the bottom means pulling against the weight of all the stones on top of it, unless you play "pick up sticks" with it. I would recommend not destroying a good knife for this sort of thing and say a pick or a spade of some sort might work to loosen the mortar. Quite loud I'd imagine.

Look at the mortar. If it already has visible cracks, it's very dry and brittle. I can't say it's the easiest thing to get rid of, but it's easier than new.

Sarpedon · Apr 4, 2011

while age might do it, I doubt that it could be done deliberately, by sabotage, without anyone noticing. the walls at the top of the battlements (or crenelations) were thinner than the walls in general, they were still 1-2 feet thick. You could chip away mortar, but you'd probably only get a few inches in. This would not be enough.

When you lean against a wall, you apply force to it like a lever. The area of the wall closest to you will suffer tensile stress, while the wall on the opposite side will suffer compression stress. I assume the sabatour will not dangle over the wall to chip away at the mortar on the far side, which will be the part that is most relevant. Masonry is strong in compression and weak in tension, so the part of the mortar that the sabatour is most likely to get at is the part that isn't doing any work anyway.

Castles are dangerous places, I would think there are easier ways to kill someone than this.

WriteKnight · Apr 4, 2011

Easier to sabotage a hoarding.

http://en.wikipedia.org/wiki/Hoarding_(castles)

Essentially covered wooden 'catwalks' that hang over the edge of the wall.

A hoarding was a temporary wooden (shed-like) construction that was placed on the exterior of the ramparts of a castle during a siege.

The purpose of a hoarding was to allow the defenders to improve their field of fire along the length of a wall and, most particularly, directly downwards to the wall base.
The latter function was capably taken up by the invention of machicolations, which were an improvement on hoardings, not least because masonry does not need to be fire-proofed. Machicolations are also permanent and siege-ready.

Buffysquirrel · Apr 5, 2011

If the wall was made that unstable, I think the character would notice as soon as they leant their weight on it. There would be 'give' or movement in the stone.

WriteMinded · Apr 5, 2011

Oh woe. Will no one around here ever say what I want to hear?

After being stuck for weeks, I came up with the perfect incident, which covered all the elements I needed, only to find out it's too implausible to work. So - I guess I need to figure out a perfectly reasonable explanation for how a major operation has been performed on a stone wall without anyone noticing the loud banging or the guys dangling from the wall wielding picks.

I'm thinking if this were a movie, no explanation would be needed. "Oh my. Someone deliberately loosened the stones," would suffice. In fact, if I encountered this scene in a book, I'd never have questioned it. But - I'm learning everyone is not as gullible as I.

Nick Blaze said:
I would recommend not destroying a good knife for this sort of thing and say a pick or a spade of some sort might work to loosen the mortar. Quite loud I'd imagine.

That's what my husband said, "Loud." I didn't like his answer so I brought my question to AW - only to get the same thing.

Sarpedon said:
Castles are dangerous places, I would think there are easier ways to kill someone than this.

Yes, there are but it was intended to look accidental, at least until someone says, "Hey there, I do believe this was intentional!" Then the evildoer behind it all would get terribly upset about his beloved lord almost being murdered. This was an opportunity to emphasize how important this particular friend is to the MC and to show the lengths to which he'll go to save him. It takes place a month before the big guy gets murdered.

Thanks for the info on stresses.

WriteKnight said:
Easier to sabotage a hoarding.

http://en.wikipedia.org/wiki/Hoarding_(castles)

Essentially covered wooden 'catwalks' that hang over the edge of the wall.

A hoarding was a temporary wooden (shed-like) construction that was placed on the exterior of the ramparts of a castle during a siege.

I'll look into hoardings. This place is not under seige but they have reason to be on the defensive and they're doing a lot of building in the village and inside the castle walls. It's conceivable the MC might stand out there - if I can figure out how he would get onto it. Did they have an opening in the wall to get to it? Did they climb over? Maybe I can find a picture?

Buffysquirrel said:
If the wall was made that unstable, I think the character would notice as soon as they leant their weight on it. There would be 'give' or movement in the stone.

Yes, one of them notices but he's a little imaginative and is then distracted by something he sees, but no, the other guy doesn't notice. I thought his kicking it and laughing would cover that. No?

WriteKnight · Apr 5, 2011

Here's a good pic from Caerphilly castle.

http://www.castlewales.com/hoarding.html

The top pic is the inside view, showing how they would step over/through the spaces in the crenelations to gain access to the other side.

The bottom view shows a crossbowman firing through tiny openings - and another defender dropping stones through a hole in the floor.

Hoarding were built for seigework - but might be left in place for any length of time.

WriteMinded · Apr 5, 2011

WriteKnight said:
Here's a good pic from Caerphilly castle.

http://www.castlewales.com/hoarding.html

The top pic is the inside view, showing how they would step over/through the spaces in the crenelations to gain access to the other side.

The bottom view shows a crossbowman firing through tiny openings - and another defender dropping stones through a hole in the floor.

Hoarding were built for seigework - but might be left in place for any length of time.

Perfect! Thank you. I've been to the Castle Terminology page and thought I'd visited all the links but guess I missed this one.

Buffysquirrel · Apr 6, 2011

WriteMinded said:
Oh woe. Will no one around here ever say what I want to hear?

Yes, one of them notices but he's a little imaginative and is then distracted by something he sees, but no, the other guy doesn't notice. I thought his kicking it and laughing would cover that. No?

Tricky. I think even if we don't notice when something's 'off', the autonomic systems do, and would attempt to rebalance your character, or at least give him a mental nudge. I think he'd have to be pretty dozy tbh. Of course, if he'd had a little to drink, that would throw the systems off nicely

.

Breakaway Stone Wall?

WriteMinded

Derailed

mcamp

Hooga Man

WriteMinded

Derailed

Nick Blaze

Jun-Ikkyu

Sarpedon

WriteKnight

Arranger Of Disorder

Buffysquirrel

WriteMinded

Derailed

WriteKnight

Arranger Of Disorder

WriteMinded

Derailed

Buffysquirrel