Rope and edges

Clearly having your rope run over edges is bad (and potentially lethal) thing to do. I've been wondering how to avoid having this happening while leading on single pitch routes where there are multiple roof sections, and where you need to use the hardware that's been place. It's particularly bad when its not safe to rappel from the top and you need to lower to clean. I run into this problem fairly often, and my rope of one year is getting really fuzzy because of it, not to mention my climbing is terrible because all I'm thinking about is the rope cutting.

I understand that you can use runners to keep a rope in a line, or to allow it more movement and reduce rope drag, but I don't understand how to stop it from running over an edge like that. Even if you extend the draw below the roof section, its still going to run over the edge when you clip the next clip or fall or take (not to mention you then have your sling over the edge too).

I've put a picture in for an example.

This is somewhat rock type dependent; on the granite and sandstone that I typically climb on there aren't a lot of sharp edges like the ones you might find on fractured basalt. 

I worry a lot more about ropes moving parallel to a sharp edge then ropes moving perpendicular to a sharp edge. When a fall might drag your rope along a sharp edge that's when I would really look for a way to runner it out of the way.

One of the most common scenarios for a sharp edge damaging a rope is in a top rope anchor or jumar anchor extended over an edge that is cyclically loaded and unloaded. This puts a lot of wear very quickly in a small area of your rope or runner.

FWIW the piece after the circle on you photo might benefit from a longer runner to reduce the pressure of the rope on the edge.

David Hous wrote:

This is somewhat rock type dependent; on the granite and sandstone that I typically climb on there aren't a lot of sharp edges like the ones you might find on fractured basalt. 

I worry a lot more about ropes moving parallel to a sharp edge then ropes moving perpendicular to a sharp edge. When a fall might drag your rope along a sharp edge that's when I would really look for a way to runner it out of the way.

One of the most common scenarios for a sharp edge damaging a rope is in a top rope anchor or jumar anchor extended over an edge that is cyclically loaded and unloaded. This puts a lot of wear very quickly in a small area of your rope or runner.

All of the rock I've been on so far is granite, and none of the edges have been sharp enough to cut skin on, but it still frightens me. (I'm a bit of a novice when it comes to rock type, so I'm not sure how sharp is sharp). Is there a serious risk to the rope dragging perpendicular other than wear and tare to the rope? I would assume if you're unlucky enough it could skin the sheath off the rope.

If you are climbing cracks, or if there is a bolt close to but after the roof, toss in a piece of gear, and hang an edge protector on it.  Check out the Fish website, I believe 

it's Fishproducts.com.  They have something called a Grain Tamer that is designed for protecting ropes that are crossing edges.  And yes, extend your webbing as 

much as you can, to increase the relative radius of the edge the rope is crossing.

You don't need to worry about edges a whole lot. Like the person above mentions, if the rope is running across the edge then it's just going to fuzz the rope and extending the slings is the best way to negate that, but sometimes you just have to deal with it. Some areas are worse than others for this. The time you really need to worry about is if your rope is going to slide along the edge like the way a blade would cut through something. That's where things can get bad/scary. If you have that situation then find a way to put in directional to pull the rope away from the edge. You'll have more rope drag, but rope drag is a lot better than a cut rope. 

Lauren Baglee wrote:

I understand that you can use runners to keep a rope in a line, or to allow it more movement and reduce rope drag, but I don't understand how to stop it from running over an edge like that. Even if you extend the draw below the roof section, its still going to run over the edge when you clip the next clip or fall or take (not to mention you then have your sling over the edge too).

With the piece below the roof extended enough the upper piece/draw will only be pressing the rope against the upper face. To some degree it will end up running over the edge though, not much you can do to avoid that. You're likely over thinking and underestimating the rope (I know I did when I first start climbing). Yes it will abrade your sheath, but it take a really sharp edge to do real damage. Ropes are wear items, just replace them.

Depending on the features of the rock you're climbing, it is often times helpful to extend the next piece after the roof/ledge, etc. This is particularly true when the next piece is further back from your last piece. Its difficult to tell what's going on in your picture, otherwise I would comment on that specifically.
I would be wary of getting it into your head that ropes over edges are not something to worry about. While it is true that a rope over the edge is not always, 100% of the time bad, falling into the practice of not caring can be dangerous.

Edit to Add: The edge in this video isn't exactly a knife blade but definitely ruins someones day. (make sure to scroll to first post)
https://www.mountainproject.com/forum/topic/112789856/michele-caminati-rope-break-and-ground-fall#ForumMessage-112801343 

unicore ropes if you know you're going to be dealing with sharp edges.

https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=unicore+ropes&tbm=shop

Sure there are times I worry about sharp edges and use half/twin ropes. That's not at most crags though.