Re-Roofing 30x40 Shed

SkiB · Nov 25, 2019

Re-Roofing 30x40 Shed

I have a 30 depth x 40 width semi flat roof shed with a 2.5/12 pitch. The OEM roof has lasted some 50+/-years(?) and is slowly blowing off/spiting nails, rusting away. The building is salvageable.

Currently, I m repairing/replacing any structural wood and purlins boards in need of, as required. In addition, re-leveling the structure best I can. The leveling won t be perfect, but better than it current is.

Next year (spring 2020) project will be to re-side all walls and build new sliding doors with metal rib-metal sheathing over the weathered existing pine TG. At that time, I will be shortening the back wall to a 24 depth. This wind/weathered battered (western) wall is the worst condition of the entire building. Besides that, 4-1/2 of the building is "technically" on the Neighbor s land, which isn t a problem as legally all is good, plus having great neighbors helps. I just feel this is just another reason to to shorten up the back wall.

I m currently building a new header (pole construction wall vs the existing footer/block fountain) to support the lower end of all rafters (which will also assist in leveling).

MY QUESTION:
Before purchasing/installing my metal roof, what suggestions can be offered on the sheathing length?

2 thoughts at this time.....

Although theses are not my actual measurements, just to provide an example.

1) Would you purchase 30 length, then "shear" off what s not needed when new construction begins in 2020? Or.....

Would you purchase 24 pieces, then slip/tuck in a +6 piece to cover the remainder?

This building will always be a shed, so just trying to keeping costs at a minimum. Although the OEM had no vapor barrier underneath the metal and instead of me buying/installing all the fancy barrier stuff out there, would/could a simple layer of 30# roofing felt provide some protection?

Scott 730 · Nov 25, 2019

Steel roofing panels can be ordered in 1" increments here. No need to waste or overlap anything on a 30' building.

Moonlite37 · Nov 25, 2019

Probably a supplier like Scott has. just check

paul · Nov 25, 2019

You are going to roof a shed, then later move the back wall in to make it a shorter shed, and make one slope of the roof shorter.

So you want to know if you should make the tin the shorter length and add on, or make it the current length and cut it back?

Whew, lot of work there to make a smaller building and waste extra tin.....

I would get it all done at once and use the right side tin.

Or maybe use the 24 foot pieces and let the extra water run on the old shingles for a year. Why waste the extra tin to protect something you aren?t going to be using.

Maybe I misunderstand.

Paul

Russ from MN · Nov 25, 2019

I have always wondered about expansion and contraction on a really long piece of steel, I think I would use 2 shorter sheets with an overlap. A 30 foot sheet will change almost 1/2 inch in length from summer to winter, I would think that would shear off some screws or at least leak. But, I have never built anything that big, I did put 24 foot on the walls (horizontal) of our cabin, but it's on the N side, and white.

Michael Soldan · Nov 25, 2019

We have a steel supplier in our area and they will cut sheets to whatever length you want , with some planning you wont have to cut anything. I see a lot of steel buildings going up and full length sheets seem to be the norm

495man · Nov 25, 2019

I ordered full length sheets cut to the exact inch.

Did a whole building and only cuts were the angles for the gables and spliting two sheets in 1/2 lengthwise for walls.

MarkB_MI · Nov 25, 2019

There is no way I would plan to cut an exposed edge of steel roofing. It's going to look like crap, no matter what you use to make the cut. Also, the longer the sheet is, the heavier it is to handle and the easier it is to damage it in handling. So I would rule out full-length sheets.

As for installing short sheets at the bottom and removing them later, I guess I don't know why you would buy steel roofing that you know you're going to tear off. I would cover the roof you know you're going to tear out with something cheap. Felt might be a little marginal, but roll roofing should do just fine.

495man · Nov 25, 2019

(quoted from post at 15:05:15 11/25/19) There is no way I would plan to cut an exposed edge of steel roofing. It's going to look like crap, no matter what you use to make the cut. Also, the longer the sheet is, the heavier it is to handle and the easier it is to damage it in handling. So I would rule out full-length sheets.

As for installing short sheets at the bottom and removing them later, I guess I don't know why you would buy steel roofing that you know you're going to tear off. I would cover the roof you know you're going to tear out with something cheap. Felt might be a little marginal, but roll roofing should do just fine.

If you cut a sheet in half and the cut edge is at the corner, you use a 90 degree trim piece to cover the cut edge and give a smooth 90 degree finished corner. My metal supplier offered almost every trim you could think of plus custom options.

I had approx 20 foot long sheets and as long as you aren't working in the wind and you "cup" them in a U shape (not bend them!) you can easily carry and install them damage free.

VADAVE · Nov 25, 2019

You have received some good comment back.
My is something to think about. I am located 30 miles west of the Chesapeake Bay in Virginia, we are subject to hurricanes. When the last one threatened us, or was it several before, I checked with my insurance agent only to learn an open shed is NOT covered for wind damage. But doors count as walls. So I put on doors. They are sliders and they are tough to deal with, the wind shakes them back and forth and only one half of the doors can be opened at the same time. Doors that open up, either roll up or fold up, would work better BUT they cost more. Either way if the wind knocks it down or rips the roof off at least insurance will fix it.

Stephen Newell · Nov 25, 2019

Assuming there is a peak in the middle I would get 16' sheets if available and cut them to fit letting the metal overhang five or six inches. The metal is a little difficult for the DIY to cut. If you order a
specific length they can cut it for you. If you use R-panel you can get preformed ridge caps that would fit the metal exactly. Just use tacky tape on the seams with metal to metal screws.

For the barrier sheet you might use poly tarps. Another option would be synthetic felt which is pretty much the same thing.

The metal I use comes in 36" wide sheets. If the building is 40' that would be 27 sheets cutting one lengthwise to make fit.

MarkB_MI · Nov 25, 2019

> If you cut a sheet in half and the cut edge is at the corner, you use a 90 degree trim piece to cover the cut edge and give a smooth 90 degree finished corner. My metal supplier offered almost every trim you could think of plus custom options.

If you cover a cut edge with trim, it's no longer exposed. But I've never seen an overhanging eave covered with trim.

> I had approx 20 foot long sheets and as long as you aren't working in the wind and you "cup" them in a U shape (not bend them!) you can easily carry and install them damage free.

There's a difference between handling 20 foot sheets and handling 30 footers. As it is, he's looking at ~25 foot sheets, which sounds plenty long to me.

JimKS · Nov 25, 2019

I worked as a service tech and installer for a rollformer manufacture. You can order any length you want up
to 50 feet from most suppliers. The longest I ever made was 108 feet. What a bear to handle it took 8 to 10
men. It was for a US government job. they would not allow any horizontal seams. Trucking was also a
nightmare.

Jim

SkiB · Nov 25, 2019

(reply to post at 09:33:10 11/25/19)

Thank you all for your thoughts.

Scott730: I realize the metal can be cut in 1" increments. When project is final next spring, I am planning to have 1" over hang over the front and rear walls/facial.

Paul: Yes, removing 6 of the building as wall structure and cement block are very weathered (rot) from years and years of rain/leaks. There is only 1 pitch on this roof, no peak. A new pole/post wall structure will be installed vs a new footer and cement block ($$$). The salvaged 6 piece (whether cutoff from the overall 30 or new 6 piece slipped-lapped underneath the 24 ) after shortening the building, will not be wasted as I can use these on the siding project.

Russ MN: good thoughts on expansion/contraction. I will be purchasing painted Galvalume vs Galvanized metal. I will used Light Gray or a White in color. My thinking is there are pretty much 3 standard roof coatings on the shelf. White, aluminum and black.

Michael Soldan: I agree, that s one of my thoughts by installing the two pieces vs one. I have an 18 trailer and think I can place the 24 pieces on it (with some support). I ll save the transportation charges if I can can do.

495man: heck yeah, yes, I ll have them cut when doing the siding project. The less I have to fool with snippets, the less blood cuts I ll have- haa.

MarkB MI: my thoughts also. I guess the best way to get a straight line cut would be with a saw, and that s not going to happen as the paint will burn. Snips/electric shears is the only way to cut painted metal and I will agree with you strongly, hard to get a straight line.

Vadave: when I purchased this property, I decline insurance on this building. I will be insuring it once I get the roof on, then up the value $$ after the siding and doors project are installed. Currently are 4-TG pine sliding doors across the 40 width. What monsters weigh these are. I will build a steel framed slider doors (kit I believe) for two of the four. I ll close off/ side the other two as I am planning to install a 10x10 overhead on another wall.

Steven Newell: as I mention above, no peak, just a 2.5/13 pitch. Tacky tape, I believe the supplier offers this and probably a great item to use as the flat type pitch on this roof. I ve not priced barrier material yet. Maybe it s the same a dry felt? I just wondered it felt paper would work? You refer to the poly-tarp, I assume this is/are the tarps sold at the big box stores with the eyelets on the outer edge?

Everyone: Thank you for your thoughts/ideas! I appreciate others viewpoints. I believe I will go with the two piece (24/6) design per the overall length. I maybe be able to install the 6 ers without drilling many screw holes. My thinking is I slip it up and under the 24 piece, I maybe able to retain the far edge in place by screwing down a 2x4 a top of (minimum screw holes) this camping it in place until spring.

JimKS · Nov 25, 2019

If I am reading right you are thinking of end lapping panels they need to over lap 12 inch to avoid
siphoning.

Jim

MarkB_MI · Nov 26, 2019

You don't need to "slip" the short pieces under the long ones; just install them first. That's how you normally install roofing. Be sure and make the upper sheets long enough that you'll have an overhang when you remodel the building. And make sure and drive the screws that go through both sheets high enough that they're not going through the overhang. (Otherwise you'll be looking at those holes for a long time.) You are using screws, right?

495man · Nov 26, 2019

(quoted from post at 18:04:20 11/25/19) > If you cut a sheet in half and the cut edge is at the corner, you use a 90 degree trim piece to cover the cut edge and give a smooth 90 degree finished corner. My metal supplier offered almost every trim you could think of plus custom options.

If you cover a cut edge with trim, it's no longer exposed. But I've never seen an overhanging eave covered with trim.

> I had approx 20 foot long sheets and as long as you aren't working in the wind and you "cup" them in a U shape (not bend them!) you can easily carry and install them damage free.

There's a difference between handling 20 foot sheets and handling 30 footers. As it is, he's looking at ~25 foot sheets, which sounds plenty long to me.

I agree you don't want an "edge" like an eve to have a jagged DIY cut, order them to exact length. I cut my gable angles with a put-on-backwards electric circular saw, ran the saw on the back side (flat) of the sheet and the cuts looked decent enough. No way would I want to try to make a perfect 90.

I might rethink handling a 25 alone, would likely want two people on it. The 20's were ok for one guy to handle.

495man · Nov 26, 2019

(quoted from post at 04:25:47 11/26/19) You don't need to "slip" the short pieces under the long ones; just install them first. That's how you normally install roofing. Be sure and make the upper sheets long enough that you'll have an overhang when you remodel the building. And make sure and drive the screws that go through both sheets high enough that they're not going through the overhang. (Otherwise you'll be looking at those holes for a long time.) You are using screws, right?

Yes use screws, I am redoing some roofs now that were nailed back in the day, 2" spiral nails with zinc washer, some 2" spiral with rubber washer, the nails have completely backed out and actually fallen off the roof.

caterpillar guy · Nov 27, 2019

I would stay with full length sheets. If you need to get them up on the roof from the ground I have done it both ways. One is to use extension ladders for a slope, to slide them up with a hole punched in the top edge. To pull with a wire having a rope attached. The other and better way was with a telehandler. Put a couple of planks across the forks laying the steel on them to lift them up so the sheets can be put in place. Several sheets will help hold rigidity to them. They can stand to be over hanging the planks by 4-5 feet without kinks or damage.
I would get the heaviest steel I could get like 24 ga., and let them stick out on both ends a few inches like 3-6. This will help with water not running back under at the eve end with your flat slope. Also will help with protecting the top edge of the wood. I would also leave the top row of screws out. Till I got my piece in under the top edge, to catch any water that might get under the edge. Then use the same screws to hold both on. 24ga. will be rather stiff and will hold well against wind and flexing. I would also screw it on the top of the ribs with your flat roof, so water doesn't run in under the screw heads. But then we always put them in the top even on a 12 12 roof.

Re-Roofing 30x40 Shed

SkiB

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Scott 730

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Moonlite37

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paul

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Russ from MN

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Michael Soldan

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495man

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MarkB_MI

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495man

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VADAVE

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Stephen Newell

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MarkB_MI

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JimKS

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SkiB

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JimKS

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caterpillar guy

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