Sheeting a (faux) Tin Roof Straight

[used red MN]

You mean the board that the tin sits directly on?

Yes, I thought the waviness is what your main concern was. If you take your time with your angle grinder and cut-off wheel any slight variations in the cut edge will probably only be noticed by you. And don’t get the idea that I accept slouch work, I’m pretty particular.

EDIT: I have 3 young kids (6 , 4 , 6 months), a wife, a dog, a 110 year old Studebaker,………

Quadruple !!!!
You better corner both the wax and candle markets!!
Edit: If you need some ridge cap to use as suggested and can wait. I could get you some when I go back to my home state of KS. I’ll screw them to a plywood strip and ship them to you UPS.

 

[MM-TX]

haha, I don't know everything and want it all to be a perfect as possible. I get stumped on stuff and never get it done.

So when you said straight I thought you meant flatness. If you start the first piece 90 degrees to the outside edge the outside edge will be straight without jaggies. The 3-4-5 triangle you can make, suggested by several, will get you there. I have tried all the ways to cut tin and get the best result with an 4in angle grinder and a thin Zip disk by hand on a straight line.

 

[used red MN]

I think if GL sees a couple of those pictures he going to get a bit aroused!

 

[used red MN]

The 3-4-5 triangle you can make, suggested by several,

I’m coming around now… a “3-4-5 square” as Jim called it is a built tool type “square” such as a carpenter’s square.

 

[MM-TX]

I made a 3-4-5 with lath. Light enough and stiff enough it’s easy to use. It hangs on the wall for next time.

 

[RTR]

So when you said straight I thought you meant flatness. If you start the first piece 90 degrees to the outside edge the outside edge will be straight without jaggies. The 3-4-5 triangle you can make, suggested by several, will get you there. I have tried all the ways to cut tin and get the best result with an 4in angle grinder and a thin Zip disk by hand on a straight line.

Yes I meant to make them straight. at the outside visible edge. I feel like when cutting pieces, they can easily get crooked because they all will be short pieces cut to each spot. I got a small trailer load of the tin where my boss had a barn torn down. Alot of it is crinkled up like that but I was planning to just use the "straight" pieces since I'm cutting short pieces anyways. I realize I need to add some supports under the corner piece but haven't because I don't really know how to go about it. Should I put all the tin up and then pop a line and use my grinder to cut the edge after it is installed?

 

[MM-TX]

Yes I meant to make them straight. at the outside visible edge. I feel like when cutting pieces, they can easily get crooked because they all will be short pieces cut to each spot. I got a small trailer load of the tin where my boss had a barn torn down. Alot of it is crinkled up like that but I was planning to just use the "straight" pieces since I'm cutting short pieces anyways. I realize I need to add some supports under the corner piece but haven't because I don't really know how to go about it. Should I put all the tin up and then pop a line and use my grinder to cut the edge after it is installed?

For me it's easier to just cut them square on a sawhorse. use your 3-4-5 and a sharpie. You use the outside purlin (flat board across the rafters) as your constant. square the first sheet to that outside purlin with your 3-4-5 regardless of if it lines up perfect with the wall. Overhang x inches. put 2 screws so it stays put. Next sheet overlap one or two corrugations, line up with the first sheet and measure the other corner overhang from the purlin. Make the overhang match. If it doesn't overlap perfect you can't see that and you're not keeping out rain. If all is square it will overlap just fine. Corrugated tin is never perfect if it squashes a little on one end it is a little wider.

To figure out the corner I would lay a new loose purlin on each roof and slide them to meet just so you can see if you want to leave what you have or adjust them all a little. The two roofs being different length dictates where they come to a point. Play with your boards to figure out how you're going to handle that. You can let your purlins hold up a jack rafter or leave it out and just have them stop at the corner if you have each purlin cross at least two rafters. Once finished it will look great.

If you don't have old ridge cap that has the same patina you can cut a strip, 8-10 in wide with the corrugations as long as you need and bend it in the middle. You don't have to have a ridge cap but it will help hold up anything a little light on structure and help blend all that is going on in the corner.

 

[Scott 730]

Should I put all the tin up and then pop a line and use my grinder to cut the edge after it is installed?

^^^YES^^^ Don't make this harder than it needs to be.

 

[Southern Ray]

I think this is what you want to do. It can be done. Determining the angle of that center spine is the most challenging.
This piece is made with straight 45* angles. The center spine I cut out of a piece of 4 X 6 lumber.
The two roofs must be the same length to match up right.

 

[Ray,IN]

Man, I just gave away approx. 60 sheets of used galvanized roofing to a scrapper. I had no clue it's valuable for other uses.

 

[want@1070]

haha, I don't know everything and want it all to be a perfect as possible. I get stumped on stuff and never get it done.

I like pics

 

[RTR]

As far as the screws to hold it down goes, I can always get new ones and throw them in some muriatic acid for a few minutes to rust them up.

 

[MM-TX]

@RTR If I was doing it I would not mess with a jack rafter it will look clunky and be fiddly to put there. I'd re-space the purlins where they match up better at the corner. Long rafter a little farther from the rafter tail, short a little closer. Don't mess with a compound miter cut if you don't want to, just do straight angle. Make an old farmer tin patch with tin across the corners where they meet. Nails will be hard on those bouncy boards so use little round head screws and drill the tin.

 

[MM-TX]

As far as the screws to hold it down goes, I can always get new ones and throw them in some muriatic acid for a few minutes to rust them up.

These will disappear on your tin

https://www.homedepot.com/p/Teks-9-x-1-in-Steel-External-Hex-Head-Washer-Sharp-Point-Roofing-Screws-120-Pack-21400/100128842

 

[RTR]

@RTR If I was doing it I would not mess with a jack rafter it will look clunky and be fiddly to put there. I'd re-space the purlins where they match up better at the corner. Long rafter a little farther from the rafter tail, short a little closer. Don't mess with a compound miter cut if you don't want to, just do straight angle. Make an old farmer tin patch with tin across the corners where they meet. Nails will be hard on those bouncy boards so use little round head screws and drill the tin.

View attachment 161971

View attachment 161972

I like the way that looks.

 

[Rbellucci]

Start with a straight reference line. Use a chalk line across the top of your overhang. That's your guide. Cut the tin with a grinder and a thin metal cutoff wheel. Wear safety glasses. Overlap each sheet by at least one rib. Screw down starting from the center and work outward. For the corner, miter the tin at 45 degrees if you can. If not, overlap the sheets and run a trim piece to hide the seam.

 

[RTR]

I got back on this and here is what I’ve completed. It appears that it is going to have to be mounted much lower?? When I layed the thin strip of wood up there to see how it would lay out, it looks like it is too high. I measured the 2 support 2x4s on either side of the corner and made the center one the length the difference of the 2. That way the transition of the tin from one side to the other should be a smooth taper. Please help me understand what I’m doing wrong

 

[MM-TX]

I got back on this and here is what I’ve completed. It appears that it is going to have to be mounted much lower?? When I layed the thin strip of wood up there to see how it would lay out, it looks like it is too high. I measured the 2 support 2x4s on either side of the corner and made the center one the length the difference of the 2. That way the transition of the tin from one side to the other should be a smooth taper. Please help me understand what I’m doing wrong

I've been told experience is what you get when you don't get what you want . By that definition I have a lot of experience. I drew a few lines on your pix to show what you are fighting. If you are going to keep the two roofs as they are. They are at different height and length so they don't line up and you may not ever like the transition they create. If you are going to keep them as is and want 3 flats and 2 ridges, take out the transition rafter, put on your purlins then set that rafter to them. It will fit but still look crooked.

If you are building a wrap around roof of different lengths you make the tails the same height from the ground and let the pitch be different. That way they can die into each other.

If you don't want to go to that trouble just don't join them, let them be 2 separate roofs. I think that would look fine, let your tin hang over each last rafter into that gap 3-4 inches it will help with aesthetics.

 

[MM-TX]

This is what you have going right now. If you do this just extend your purlins to meet and let them set both ends of that transition rafter. Probably look fine when finished. You can really get buy with a lot of odd joinery if you just finish it and are not overly critical. It's a very forgiving style.

If I was going to do it that way I would probably do it more like this:

 

[RTR]

I made the one roof shorter becuase of my door and after I did that I like it because I think it will help with keeping that corner out of the way walking around. It "shaves" it off. I really wanted to run my tin all the way across and cut it at an angle in that corner (hip). Then run the other across the same way and just transition the bottom of it like you drew that angled red line to meet the 2. Then I could put a bit of flashing on that joint. How should I build it given that is what I want to do?