attaching eye-bolt to roof ridgeline

Question

I would like to attach an eyebolt to the ridgeline of my metal roof. I can then attach a rope to that when I need to work on the roof. I am a climber and have the knowledge and gear to secure myself. The rope is mainly to allow me to get up the 10/12 central part of the roof (the ridgeline of which I'll mount the eye-bolt), and not slide off the adjacent 5/12 portions of the roof. It will not be subject to dynamic loading (catching falls); the biggest loads it will sustain are when I haul on it to get up the 10/12 roof (it's impossible otherwise, very slippery).

Since the ridge cap is just a fairly flimsy piece of galvalume, the eyebolt must be secured without reliance on it (and RTV silicon caulked to it). My plan is to drill a hole through the ridge cap, the eyebolt will come through that, and then be attached to the rafters with two u-bolts. Since this is the ridge, it's where the rafters meet. So additionally, I will reinforce the rafters with two triangular shaped steel plates (one on each side of the area where the rafters meet); these will be bolted through the rafter with 2-3 bolts, and then the u-bolts will go through them as well.

This picture shows the detail.

Answer 1

If I may suggest an alternative since putting a hole in any roof is better avoided.

I have a 10/12 pitched roof and I use an extension ladder with a stand-off stabilizer to reach the peak.

The ladder is laid flat on the roof with the stabilizer pointing skyward. Extend the section and slide upward towards the peak and then flip the ladder so the stabilizer hooks over the peak.

Climb up the rungs which offer both hand and footholds. Once you’re at the peak, tie off your safety line, hoist a plank to lay on the opposite side of the peak and insert through the top rung. Lash it off or use pipe clamps and you’ve reinforced the setup. I have used it to rebuild chimneys, antenna work, placing hundreds of pounds of brick, etc... on it.

Answer 2

It may not look the best, but if you're going to install a fall arrest system on your roof this seems like a cheaper and tested solution. It's best not to try to MacGyver solutions when life safety is involved. I'd suggest covering the fasteners with a waterproofing tape once the system is installed to prevent as much water damage as possible.

Answer 3

Here's what I ended up doing:

1. I mounted a piece of 6x6 oak between two rafters, just down from the ridgeline, butted flat against the roof underlayment, and secured with three anodized 4" timber screws through the rafters at each end. I did two of these, one of each side of the ridgeline.

2. I sourced some 1/2" by 4+" stainless steel shoulder lag eye bolts.

... and screwed them through the roofing metal and into the oak 6x6 pieces. I obtained some nylon washers (called a company that manufactures them and asked for samples) to use where the bolts penetrated the roof, to forestall galvanic corrosion between the SS and the galvalume. I sealed the penetration throughly with RTV silicon.

3. I sourced some 3/16" wire rope and hardware to make loops at each end, and used this to tie the two eyebolts together (outside, on top of the roof). I covered the wire rope with UV resistant plastic tubing where it lays over the galvalume ridge cap, again to avoid galvanic corrosion. The purpose of this is to create redundancy in my anchors: if the one I'm secured to should fail, the wire rope will keep me secured to the other. This will fail if the circular eye of the bolt fails, but this seems an unlikely failure point - the whole thing seems extremely secure, including the way I mounted the eye bolts to the 6x6 pieces. The only part that worries me a little is where the shoulder of the eye is attached to the threaded shaft of the bolt.

As far as using, some of this will only make sense to climbers:

1. I attach a piece of climbing rope to a 'biner with a retraced-figure8. Standing up through a "roof window" openable skylight in the loft, I use a stick clip to attach the 'biner to the near-side eyebolt.

2. I attach the rope to my harness with a grigri, with a safety knot below the grigri. I adjust the rope length as I move about the roof. I could move the 'biner to the other eyebolt when I go over the ridgeline to the other side of the roof.

3. When done, I do a procedure somewhat like cleaning a sport climb. I secure myself to the near-side eyebolt with a sling. Then I detach the rope and 'biner from the eyebolt. I thread the rope through the eyebolt and tie it to my harness.

4. Then I rappel down from the eyebolt to the roof window, using the grigri.