Bolting in limestone

Any advice on what to do when bolting in limestone and you can only drill about 2" of solid rock before hitting a void to where a 3" expansion bolt no longer works? Would glue-ins be better? Thanks

Find a spot where the rock is solid. :)

Seriously, you are probably drilling through flow stone which often has pockets/soft areas beneath a harder layer. I wouldn't trust a bolt of any kind in a matrix such as this. Try to find a sold area to place your bolt, otherwise you might six inch or longer bolt to see if you can find some solid rock beneath the soft.

You do not place a bolt where there is a void. Ever. The rock is already unstable and a fall could easily break off that flake. I left an entire crag in Wyoming because of that problem. You just found out you have a toprope route.

The short answer is probably to drill deeper. Drilling deeper would help, assuming that you eventually get back to solid rock. And yes, glue-ins would be a good option as well. These are the strongest and do the best job of maximizing soft rock.

I have several questions/concerns about this question. First, is this pocketed rock? It is then likely that you're drilling into a pocket rather than a "void." If this is the case, you should just be able to move the bolt placement a bit and get a better hole. Second, it is also possible that as you're drilling you are moving the drill around a bit, especially as you get near the bottom of the hole and your arm gets tired. This would round out the back of the hole, making it bigger (and making it less likely for an expansion bolt to work).

If neither of these are the case, it raises big concerns about the overall quality of the rock (and thereby whether it should be bolted at all). If this is an isolated spot for a bolt, then a glue-in would be the best option. If this is a general concern for much of the cliff, maybe it should be a toprope cliff? Don't get me wrong, I've bolted plenty of choss, but I only bolt stuff that I can at least get the bolts onto totally solid rock, even if the climbing is on softer/more crumbly stuff.

Sam posted the shortest answer while I wrote my windier one. He's right.

Sketch. Sounds like even toproping there's a chance you could yard off a giant flake and crush your belayer. Ping it with a hammer on a rappell all the way down.

Drill deeper? Good lord.

Please post up where your sick new crag is, so we can avoid.

Asking bolting questions on the internet = should not be drilling new routes.

BScallout wrote:Drill deeper? Good lord. Please post up where your sick new crag is, so we can avoid. Asking bolting questions on the internet = should not be drilling new routes.

nuff said

I am simply asking for advice, if you have nothing useful to say then just don't say anything. The rock at this crag is generally good but the proposed routes are on what looks like one giant tufa. The features are amazing, however, it seems that after a few inches of solid rock there is soft, honeycomb like stuff inside. I don't have much experience with limestone so before drilling more holes in this beautiful rock I want to do more research and find out if anyone else had a similar problem.

Then ask for help from a local who has experience with this kind of rock. This is the last place you should be asking for general advice about this kind of thing.

Talk to the manufacture of the bolt you are going to use?

Sam posted very useful advice - DO NOT BOLT in any spot in the rock where you encounter a void. If you can not find solid rock, DO NOT BOLT. Yes, that means that sometimes you just can't climb certain rock.

Sam has more experience bolting limestone than nearly anyone (who isn't European that is)...

Katya wrote:I am simply asking for advice, if you have nothing useful to say then just don't say anything. The rock at this crag is generally good but the proposed routes are on what looks like one giant tufa. The features are amazing, however, it seems that after a few inches of solid rock there is soft, honeycomb like stuff inside. I don't have much experience with limestone so before drilling more holes in this beautiful rock I want to do more research and find out if anyone else had a similar problem.

Mostly we are telling you not to bother, which is saying something useful. Since you seem so persistent, Sam knows about drilling tufas.
Hilti makes an epoxy anchor system for block walls that involves inserting a 'sock' into the hole, filling that with epoxy and then inserting the anchor into the sock. I have installed manifolds weighing several hundred pounds onto block walls this way. But several hundred pounds of static weight is not the same as the Kn's of force from a fall. So getting technical data will be difficult. And then, no one knows if the rock matrix itself would withstand it either. How's that for advice?

Katya wrote:I am simply asking for advice, if you have nothing useful to say then just don't say anything.

It's very useful. Actually probably the best and most honest advice you'll get on here. You just don't like the answer. Sorry, sometimes the truth sucks.