Steep Stuff–Metal Roof on an A-Frame
Hey, this internet stuff is addictive. I’ve only had the service about 20 hours so far, and already nobody can reach me on the phone.
I’ve got a job that we put off over the winter (you don’t strip roofs up here in the winter unless you’re REALLY hungry). The house is an A-frame, the roof is 65 degree pitch, 28 feet from eaves to ridge, and is built of 2×6 T&G roof decking. The outside is covered with TWO layers of Black Joe plus asphalt shingles. The builder used 2″ roofing nails to hold it all down. I figure it’s gonna take three guys (two roofers and one helper) a whole day to strip each side, because these nails ain’t gonna pop out when I lever them with my trusty shovel.
There’s no finish inside the roof, so no insulation either. The owners like the rustic look of the underside of the T&G boards, and want to keep it that way. But they’re (understandably) tired of paying to heat the air above their house all winter. So we bought some special exterior roofing insulating panels (3″x4’x9′), and will lay that on the outside. The problem is that the owner bought a lot of surplus/recycled commercial-grade steel roofing, in 8′ lengths, and I’ve got to lay that over this insulation like big shingles. I’m worried about two things.
1) I plan to glue the panels to the roof, and then lay 1×4 furring over them laterally, screwed through them to the roof deck with 4-1/2″ lag screws. Then we’ll screw the steel roofing sheets to the furring. But that @#$%? steel is heavier than heck, and I’m worried it’ll slide down, levering the lag screws out of the deck. I can’t penetrate more than 3/4 to 1″ max into the roof; no screws may pop through to the inside where it’ll be visible. Remember, the furring will be sitting 3+ inches off the roof itself on top of the panels. I plan to lay the furring on 2′ centers, and place the screws on 16″ centers laterally. Anybody got any comments?
2) Because the finished roof will be steel, I can’t use my regular roof jacks and scaffold boards to work up the slope. I’ve thought about using pump-jacks either hanging from the ridge or firmly footed on the ground, laid right against the roof surface, but I’ve never used pumps before and I’m not sure it’ll work. Anybody got any ideas?
Ever see a DINOSAUR climb a roof…?
Replies
Any chance you can screw up from the inside to catch either the furring or at least the outer layer of the sips? If you used appropriately colored and countersunk screws, in a decent pattern, would they buy it?
Do it right, or do it twice.
ELCID--
Nah, they wouldn't buy it. The inside of the house is all big beefy glue-lams stained dark brown and then the V-joint side of the roof decking. It actually looks quite nice.
Besides, the insulation isn't sips; it's some sort of isocyanacrylate gobbledegook stuff with a built-in vapour barrier (I think; I haven't seen the stuff in 6 months; we left it in my lumberyard's warehouse over the winter). I'm afraid because the stuff is compressible to some extent that the lags may get bent downhill by the weight of the steel. If I knew how to do a drawing on the internet, I'd show you, but right now I'm just pleased to be able to find the fhb website without getting lost.
Dinosaur
I'm strictly a framer so my suggestion may show my ignorance, but could you attach nailers directly to the decking between sections of insulation?
Actually, your idea is similar to the owner's original plan. He wanted me to build a 'crib' of 2x6 on edge onto the roof deck, and then spray it with urethane foam. I wasn't too sanguine about trying to hold the 2x6's in place--it would have taken a heck of a lot of boring through 5-1/2" of wood and lots of 6" lags plus glue and I don't know what all--but it was the price of the foaming job that convinced him to do something else. There's only a couple of subs in this area that do that kind of work, and neither of these two clowns will leave the garage for less than 5 grand. That struck me--and the client--as pretty high, so the insulation money went south (the supplier for the panels is a company in the 'states).
dinosaur
working in the vertical world....
We've built alot of pocket roofs on roofs less steep than yours, using anything from 2x6 on edge up to 2x10's and insulating the bays created with rigid foam ripped to fit the bays, then sheathing over with plywood. We lay the 2x transverse to the rafters below, using them to span between them and making it a great ladder to work off of. The horizontal 'rungs' of the ladder are blocked every 8' vertically to create boxes for the rigid and act as firestop. The sheathing is run vertically rather than horizontally.
Generally we clip all the framing 2' oc to the planking or framing below and toenail elsewhere, though in your case, the steepness may dictate another method, which may involve running the 2x's vertically directly above the rafters below and clipping them together, then blocking horizontally 8' oc to create the boxes.
The spray-in foam we've found is very expensive; in our cases, we put the money into our pockets ripping up rigid (a nasty job, but wrap yourself and wear a mask) on a table saw, then using a handsaw to fit.
Good luck!
Don
You can homemade a straight ladder with a hook. Steel roofers I have seen have used 1x4's with clinched nails and pads under. The hook, bent flat steel bar. Plenty light to move around. They worked a section, then moved it over.
FHB had a steel roof article a couple of years back. Good reading for information. Check it out.
__________________________________________
Remodeling Contractor just outside the Glass City.
http://www.quittintime.com/
Edited 5/24/2003 8:25:41 AM ET by calvin
The hook that you are talking about is made by several different companys and is made to go on ladders supposed to use two per ladder
The insulation is commom in commercial roofing has a nice r value per inch in the type of installation you are talking about we usally make a grid of nailers that is the same thickness as the insulation then fill in the insulation between them....two reasons 1.condesation on the back side of the metal panel 2. makes for great bug home if not screen off real good
as to the access problem high reach man bucket comes to mind
Hey, I think Calvin and Doc are jointly getting somewhere. I had thought of using a 30' extension ladder and making some kind of hook, but the weight of it discouraged me. A 1x4 ladder with some flatbar on the top end oughta work.
Now that I've actually gone to the trouble to go into my files and look up my original drawings, I am reminded that I'd planned to lay vertical strapping down from a sort of ridge-cap made of 4x's, and then lag-screw the lateral strapping through that and the insulation to the roof. That way, the down-sliding load imparted by the weight of the steel roofing would be supported at the top face of the insulation (ie 3" above where the screw meets the roof deck) by the vertical strapping, which in turn is hanging from the ridge cap.
I suppose I could use 2x4s to build a crib--but that'd be almost as much trouble as the owner's original idea (see my relpy to SCOTCRPTNR), just shorter bolts. Besides, it would create cold spots in the roof and up here, guys, it gets COLD in the winter. People who're not used to our climate claim it's the coldest place south of James Bay. This is not true. But you do want to eat your bacon and eggs in the morning to stoke that internal furnace....
I dunno--maybe it would just be easier to run 56'-lengths of plumber's pipe-hanging strap up and over the roof from one eave to the opposite one, and the lags through that into the lateral 1x4's. Only disadvantage to that idea, it won't give me quite as much air space under the steel...
dinosaur
...creative solutions to ridiculous problems: our specialty...