When installing guys on a roof or any wood covered surface, you MUST catch a rafter!!! If you don't, you will be fixing it and using your insurance to fix a ceiling! Guy Wire Class 101
•When installing any eye hook in ANY roof, it MUST be in a rafter! If you can not hook a rafter then you have to cut a 2x4 and nail (screw is better) it in place between the 2 rafters so you have a solid place to screw the eye hook into! (if you are in a high wind zone, make sure the rafter you are hooked to has a "hurricane strap" attaching it to the top plate on the structure).•Make a small pilot hole into the roof and then turn the eye hook into the hole. Then un-screw it and squirt a large amount of silicone into it (Not the cheap stuff! Geosill 2000 works great for this - it doesn't get hard). Turn the eye hook into the roof - as you do this, you will pull the sealant down into the threads•Crawl underneath and make darn sure that the hook has caught the rafter or the piece of wood that you have screwed in place between the 2 rafters!•If you are using a hinge, make sure that at least half of the screws that you have used are in a rafter! (I say this because sometimes the center of the roof has no rafters, hence the piece of wood between the rafters). UPDATE: DO NOT use a hinge! It has come to my attention that hinges are NOT covered by ANY of the mast manufacturer's warranties! If you try and expand the mast all the way and then "swing" it up it won't work and will bend in half!!!!!•If you are using a mast that is 30' or over, I would drill a hole for every eye hook and use an eye bolt. This allows you to push the eye bolt thru and attach it with a washer and a nut on the bottom. This is a much more stable system.•Do NOT screw an eye hook into the roof decking alone and expect it to hold! On a lot of the newer buildings, they use Aspenite (flake board or OSB) and this stuff is JUNK! It can barely hold up the roof, much less an eye hook trying to hold up a 20' mast with 60 mph winds blowing against it! Even if the roof is decked with 5/8" marine grade tongue and groove plywood it will not work!•All of your guys must be centered with the mast. On most 20' masts, you will have 2 sets of rings that will allow you to use 4 wires at every ten foot level. Do NOT think that you can put up a 20' mast and only guy it at the top! (you WILL be putting this back up with the first strong wind!)•When setting up the mast, make sure that it is plumb (straight up and down) before tightening the guys.•After you have set everything up and it looks really good, go back and check it again! (With a 40' mast, you will have at LEAST 64 U-clamps holding the wires in place - 2 at the top and 2 at the bottom of every wire minimum! Make sure that all the clamps are tight!)•Only use the stranded wire (Airplane wire) to erect your mast. The cheaper stuff stretches and will become slack after 30 minutes.•Always use the heaviest turnbuckles that you can find to adjust the tension (without overkill of course!)•After you are done adjusting the tension you MUST lock the turnbuckles in place so that the wind can not wiggle them and loosen the tension. This can be done buy using a small piece of wire and looping it thru the top and bottom eye hole of the turnbuckle and twisting it together so that no movement is allowed.
I guess the moral of the story is this: Do it right the first time
or you WILL be back up there at 2AM on the coldest night of the year fixing it!