[jwi]

On easy routes there are holds everywhere so you can place your hands and feet where ever you like. You can ascend them by doing short moves and they are often not steep so lots of the pressure on the holds are down and in. On hard routes and boulders the holds are smaller and further appart, and you might have to pull hard on small features and push hard down and sometimes even out on small footholds.

This is why unprotected 5a rubble in the mountains might feel completely justified and not that dangerous while wellbolted 8a looseness is absolutely terrifying

[stone]

It's not that I don't believe you Stone, just as someone who I've known as a climber for years I'm surprised Countryfile was where you first heard of this. Did you not see the 3rd Rock saga where they had an advertising campaign featuring people climbing on wet rock? It didn't go down too well.

I missed all of that.

I suppose I've varied a lot in how much I've been on the grit, but since 2002, I've always gone at least a few times each year. I also went a bit in the late 1980s, early/mid 1990s. I've not really mixed in grit-focused circles much though I guess.

[Dingdong]

Just knowing how many noobies go out trad climbing in the wet, not being told any different who then might go on to boulder at stanage at a later date thinking it’s fine to climb on wet rock, after all they did so on their instructional course?

[JamieG]

Whether or not one human has climbed on a certain rock type in a certain location doesn't change the fact that water in any type of pore space, in this case secondary porosity induced by erosion, reduces the effective stress and therefore strength of the rock

I’m interested in the mechanics of this. I can’t understand why the pore space being filled with different materials (ie air or water or anything less stiff than the rock) would affect the actual stress on the rock. I always assumed it was something to do with chemical bonds within the rock itself changing when wet and therefore lowering its max stress before breaking. And that this only would be problem for certain compositions of rock. Ie sandstone or grit because of how they are bonded together.

Any geologists care to enlighten me? 

[Wellsy]

I was glad to see the Depot doing a vid with the Supreme Arch Militant of the Templaris Siliceous himself, Dave Parry, about wet grit

Climbing Walls are basically how 9/10 people get into it these days so they're well placed to deliver the sacred litanies and incantations

[andy_e]

I’m interested in the mechanics of this.

Since you asked...

The best way to dry a hold is to let the breeze do its job. Any heat applied (rapidly and/or above ambient temperature) to pore fluids will cause expansion, increasing pore pressure and reducing effective stress between rock grains and therefore forcing grains apart where there is no confining pressure. This leads to grain loss and erosion. If you could apply a cool air to the rock like a localised strong breeze, it would dry the holds efficiently and safely.

Except in this instance we're talking about the difference between wet and dry rock. Dry rock has effectively no pore fluid pressure, whereas when the rock gets wet and water soaks into the pore space, the pore fluid pressure increases. Rock strength is a sum of pore fluid pressure and effective stress, and if the effective stress is reduced by increasing pore fluid pressure, it takes less external force applied on the rock to damage it.

There are two types of porosity - primary and secondary. Primary porosity is a result of the formation of the rock, such as deposition of sand grains naturally having space between them. This is why siliclastic rocks - sedimentary rocks made of silicate minerals, such as sandstone, shale, siltstone, conglomerate, are weaker when wet. But fractures that form within the rock after its formation, from whatever source (loading/unloading, tectonic stress), and things like dissolution within limestones, are secondary porosity. Flakes on rocks often form through preferential erosion of certain minerals (for example feldspars and mica in our climate weather down to clays, whereas quartz doesn't weather so readily), which can allow water in behind flakes and often into secondary porosity formed from minerals themselves eroding out, weakening the rock.

Interestingly, I appear to have foreseen portable leaf blowers by about ten years in the above post...

[JamieG]

I’m interested in the mechanics of this.

Since you asked...

Ah. Interesting. So basically the void space gets filled with something essentially incompressible and that affects the stress within the rock. I am now enlightened.  Thanks Andy.

[spidermonkey09]

Interestingly, I appear to have foreseen portable leaf blowers by about ten years in the above post...

Is the TLDR drying boulders with a blowtorch bad, drying them with a fan or portable leaf blower good? 

[Dingdong]

Time to crack out the portable dehumidifier

[andy_e]

Is the TLDR drying boulders with a blowtorch bad, drying them with a fan or portable leaf blower good? 

yes

[steveri]

Small moment of good cheer: running along the top of Helsby this weekend and stopped for a peep over the edge. Some youngish guys pawing the holds on Pocket Wall and asked them if it was dry... "Wouldn't climb on it after rain anyway." Sanctimony spared.

[Fultonius]

I’m interested in the mechanics of this.

Since you asked...

The best way to dry a hold is to let the breeze do its job. Any heat applied (rapidly and/or above ambient temperature) to pore fluids will cause expansion, increasing pore pressure and reducing effective stress between rock grains and therefore forcing grains apart where there is no confining pressure. This leads to grain loss and erosion. If you could apply a cool air to the rock like a localised strong breeze, it would dry the holds efficiently and safely.

Except in this instance we're talking about the difference between wet and dry rock. Dry rock has effectively no pore fluid pressure, whereas when the rock gets wet and water soaks into the pore space, the pore fluid pressure increases. Rock strength is a sum of pore fluid pressure and effective stress, and if the effective stress is reduced by increasing pore fluid pressure, it takes less external force applied on the rock to damage it.

There are two types of porosity - primary and secondary. Primary porosity is a result of the formation of the rock, such as deposition of sand grains naturally having space between them. This is why siliclastic rocks - sedimentary rocks made of silicate minerals, such as sandstone, shale, siltstone, conglomerate, are weaker when wet. But fractures that form within the rock after its formation, from whatever source (loading/unloading, tectonic stress), and things like dissolution within limestones, are secondary porosity. Flakes on rocks often form through preferential erosion of certain minerals (for example feldspars and mica in our climate weather down to clays, whereas quartz doesn't weather so readily), which can allow water in behind flakes and often into secondary porosity formed from minerals themselves eroding out, weakening the rock.

Interestingly, I appear to have foreseen portable leaf blowers by about ten years in the above post...

Something's confusing me in that description - are you saying fluid in the pores reduces the rock's effective stress limit before fracture rather than reducing the actual effective stress? 

Because reducing effective stress sounds like a good thing in the mind of a non-geologist mechanical engineer!!

 

[andy_e]

yeah the term effective stress is a bit confusing and I didn't explain it clearly, sorry. Effective stress is the stress that acts across grains in grain-to-grain contacts, essentially (although overly simplistically) binding them together. pore fluid pressure pushes out against these grains, reducing the grain-to-grain contact strength, which is the effective stress.

[mr chaz]

Only skim read it, but this paper explains the mechanisms at work - also includes testing of Fontainebleau sandstone.

https://academic.oup.com/gji/article/192/3/1091/822850

[teestub]

I would assume things with any secondary porosity don’t last very long in the tidal zone getting battered by storms? All the coastal venues I’ve been to have seemed bomber, even Tintagel which has the sort of rock you might be suspicious of elsewhere. Can any more regular coastal boulderers comment on this?

[Andy W]

That’s kind of what I was suggesting earlier that black and white directives don’t fit all situations. If wet rock wasn’t climbed on at coastal venues many routes would never get climbed, think of dank greasy wet Cornish zawns. Coastal boulders are more likely to get destroyed by storms than damaged by bouldering. Quite a few SW venues have been developed using practices that would be unacceptable if we used the ‘never climb on wet rock’ rule. However I completely get the gist of the argument.

[Dac]

I've been thinking about this "Don't climb on wet grit", and how much that message is actually out there for people to see. Prompted by a vague recollection of one of my bouldering guides recommending not bouldering on the Roaches skyline area when wet, I thought I would have a quick squint in a few guides on my bookshelf for grit and grit adjacent rocks to see what (if anything) they have to say on the matter of wet rock.

All the more recent guides contain the usual stuff about excess chalk, minimising ground erosion, cleaning your shoes and the like; but almost none mention not climbing (or bouldering) on wet rock.

YMC Yorkshire Grit vol 1 (2012) has no mention of avoiding wet rock, so we should probably go a bit easy on Faisal, who's video prompted this whole fork of discussion, as if the 'definitive guide' has nothing to say then who's to know.

Rockfax Peak Bouldering (2014) makes no mention either. Although the 1998 version does have a specific statement in the intro for Doxey's Pool at the Roaches, saying "A weird feature of the gritstone here is that after rain it becomes softer and more prone to erosion. It is probably best to keep away after rain and not to climb here if the holds are wet"

The only guides where I found a statement in the intro about avoiding wet rock were the Vertebrae Publishing Peak District Bouldering (2011),  the Betaguides North York Moors bouldering guide (2014) and Franco's North Yorkshire Moors guide (2019).

It should be noted that the majority of my guides are at least 10 years old, but I'm surprised so few have any mention of wet rock and recommend avoiding climbing on it.

Someone else can see what the BMC  Rockfax et. al. Have to say online, I can't be arsed.

As for myself I wouldn't now climb on wet grit or sandstone, but I couldn't tell you were this convention originated from. When I started climbing (mid '90s) climbing on wet grit was definitely 'a thing'. We wouldn't go out knowing it was going to rain, but if you were at the crag and it turned a bit shitty you would often just do easy stuff in the wet. Such practices were not discouraged by any of our 'elders and betters'.

I suspect that as I got keener on bouldering then wet rock was not climbed on, not for any concerns over damage, but simply because for me VDiff in the rain isn't too bad, but trying to get up a English 6a when wet isn't going to happen.

As for people doing easy grit routes in the wet now I am a bit conflicted. I'm not convinced it is a significant risk of damage, as the holds are larger so placed under less stress and unlike bouldering you don't spend several hours and multiple attempts trying the same move off the same crimp / pebble/ smear. But as has been stated previously on this thread if you are told easy routes are OK when wet then why not lobbing off a cam behind a flake on some harder routes? Or a spot of bouldering?

[Fiend]

Apologies for mentioning you fiend. I did so because I pretty much agree with your previous comments regarding bullying v banter. I think that some of the comments on this fella go beyond banter and I don't  think live up to the standards you suggest. I don't like online assessments either which is why I wouldn't be calling him a bell end. Don't climb on wet rock is what needs to be said.

Thanks for a calm reply kac. I guess if it came out that the guy had proper mental health issues (it's all speculation so far) and these videos were the way they had to be expressed then accusations of bellendery would be reconsidered. I might be slightly biased until then as I have quite a lot of distaste for hysterical clickbait social media.

Any other thoughts about neurodivergency and behaviour I'll leave to Slabs cos she's good at it.

[kac]

No worries fiend - I have similar feelings towards influencer type click bait stuff. I just got the impression from what others said there could be more going on here. Had no idea you could buy followers! Anyway I also can't remember when climbing on wet rock became a thing - ethics always used to be about chipping, enthusiastic brushing  and pof! It was also only last year that I learnt about the risks of climbing on certain limestone types when wet so can see where stone is coming from.

[teestub]

That’s kind of what I was suggesting earlier that black and white directives don’t fit all situations. If wet rock wasn’t climbed on at coastal venues many routes would never get climbed, think of dank greasy wet Cornish zawns. Coastal boulders are more likely to get destroyed by storms than damaged by bouldering. Quite a few SW venues have been developed using practices that would be unacceptable if we used the ‘never climb on wet rock’ rule. However I completely get the gist of the argument.

Sorry Andy yes, I did mean to refer back to your post but forgot to add that in. SW coastal venues are the only paces I go where my bouldering kit includes a bucket a sponge and an old cloth nappy liner for drying off holds and dabbing on chalk!

[SA Chris]

A bucket, 2 car sponges in a ziplock and pump action type water pistol for sucking up pools plus a length of hose for syphoning pools are all useful.

[Bonjoy]

Only skim read it, but this paper explains the mechanisms at work - also includes testing of Fontainebleau sandstone.

https://academic.oup.com/gji/article/192/3/1091/822850

Interesting.
If I read it correctly, whilst it concludes that clay bearing sandstones in the study showed water weakening even at low moisture content it found that the pure Fontainebleau sandstone was actually harder at a low moisture content than when dry (all samples were weakened by high moisture content)! 

Fontainebleau sst failed to serve as an unambiguous reference rock with respect to the two clay-bearing sandstones. A behaviour apparently similar to dilatancy hardening could be observed at low moisture contents, which at the same time appears incompatible with the concept of a pore pressure. These observations may also be related to an unknown physico-chemical effect, but a conclusive microstructural scenario is missing.

[stone]

On the other hand, there's a difference between people being slated for behaviour that's actually harmful (e.g climbing on wet grit, assuming they know why that's a bad idea) and people being singled out because they're presenting themselves in a way which other people find embarrassing/uncool/"off"/cringy.
On the third hand: sometimes you just gotta go "... okay, what does this person even think 'satirical' means?" and boggle for a moment.
And in some ways -- and this is me having a visceral emotional reaction here, not necessarily thought through or at all rational -- it makes me feel uncomfortable when people decide behind someone's back that they're obviously Not Normal and should be tiptoed around, in a way which cuts them off from ordinary or authentic human responses.
It can feel a lot like "Yeah, obviously we all still KNOW this person is embarrassing/uncool/'off'/cringy, but they're defective so they can't help it, so the important thing is that we don't SAY it out loud where they can hear."

I've struggled to get my head around this thread. It really hit a nerve with me. I guess I saw someone doing a video enthusing about doing something that I also love doing (climbing outdoors). The conditions were totally awful, he included his warm up climbing that looked as ungainly as I would look first pull on the rock after a drive up from London. He seemed undimmed and radiant through it all. Perhaps the video was brash but tastes differ.

Then I saw, what came across to me as, the conformity police getting their clip books out to try and snuff it out. As I see it, people conferring  to come to a consensus as to whether someone is "embarrassing/uncool/'off'/cringy" is nothing more than them appointing themselves as conformity police. I agree being self appointed conformity police is an "ordinary or authentic human response". Loads of utterly toxic behaviours are "ordinary or authentic human responses". Obviously being snide is hardly raping and pilaging (also totally standard "ordinary or authentic human responses"). It riles me though.

[spidermonkey09]

 Stone, you've made this point ad infinitum. Other people see it differently.

[Duma]

I've struggled to get my head around this thread. It really hit a nerve with me. I guess I saw someone doing a video enthusing about doing something that I also love doing (climbing outdoors). The conditions were totally awful, he included his warm up climbing that looked as ungainly as I would look first pull on the rock after a drive up from London. He seemed undimmed and radiant through it all. Perhaps the video was brash but tastes differ.

Then I saw, what came across to me as, the conformity police getting their clip books out to try and snuff it out. As I see it, people conferring  to come to a consensus as to whether someone is "embarrassing/uncool/'off'/cringy" is nothing more than them appointing themselves as conformity police. I agree being self appointed conformity police is an "ordinary or authentic human response". Loads of utterly toxic behaviours are "ordinary or authentic human responses". Obviously being snide is hardly raping and pilaging (also totally standard "ordinary or authentic human responses"). It riles me though.

Your first paragraph is fine. Your second paragraph is just nonsense.