My shed plans: Metal roofing.

[Kenster]

I hope to start working on a shed in the very near future. I have a whole bunch of old metal roofing panels from when our roof was replaced last summer due to a hail storm. The panels are 16 feet long. They were rough cut from the roof during the tear down. (picturesbelow) In other words, they were cut between the seams, rather than pulling them apart at a seam. They all have three ridges/seams in tact and the cuts were made between seams leaving several inches overhang on each panel. Basically, the useable width of each panel is 28 inches. I will overlap each panel using the excess on each side. You can see in the pic below how much overlap there is, which should make them easy to attach without messing with the seams.

The shed will be roughly 16 x 12. The panels will be laid down lengthwise (to avoid cutting them) in an east/west orientation. I will have one end of the shed slightly higher than the other for drainage.

I'm going to use 8 ft 4x4s for my uprights, set on Dekblocks. 2x6s all the way around for facia/headers. More 2x6s lower down on three sides for lateral support. 2x4s for joists attached by joist hangers. I will have a center post on each of the two 16 ft sides. Not sure yet if I'll need a center post on the 12 foot sides?

I want to keep this as simple as possible and hope to not have to do any cutting of the metal, but if I do.... can I do it with a circular saw? I don't want to buy any special equipment, just the necessary blade, which I assume needs to be a carbide tipped blade.

Also, how should I attach the metal roofing panels to the roof framing? There will not be a solid, plywood deck, just 2x4 framing. Since I am using deck screws for everything else, would deck screws also work to attach the panels? I would have to pre-drill the panel before inserting the screw.
For what it's worth, this shed will be in a wooded area completely surrounded by trees. Not much wind gets through back there.

Of course, a portion of this shed will be dedicated to firewood. The rest is for tractor implements, etc.

Any tips or advise is greatly appreciated.

Ken

 

[gzecc]

I would probably install 5x8 plywood sheathing for structural stability and a place to screw your roofing to.

 

[bigbarf48]

My shed is built just like that, but way smaller (like 12 X 3 ) I screwed my panels right into the 2x rafters, although I had to nail in a few supports here and there (this shed build was no framing feat, I kinda just wung it)

People will likely tell you not to run the panels E/W, but mine are, and they haven't leaked yet. If you put the higher panel above the lower one (in terms of the overlap), its seems like its less likely to leak to me, water aint going back up the roof. I did run a bed of silicone along the seam for extra insurance

In terms of screws, I ponied up for the ones specifically for this application They're self-tapping, and have a rubber gasket/washer to keep things water tight. I think Id go that route rather than deck screws. If only becuase pre-drilling all those holes is gonna be a PITA

 

[Kenster]

I would probably install 5x8 plywood sheathing for structural stability and a place to screw your roofing to.

I know that would be the best way but this really has to be done on the cheap. I'm going to have enough joists that it all should be plenty stable.

 

[ClintonH]

Looks good. You can cut the metal roofing with a carpet/utility knife (I mean it). You simply score the metal with the knife (either side) and the sheet will rip on this score. I didn't believe it until I saw an Amish crew doing it this way, evening ripping 24-ft sheets lengthwise without problems.

 

[Kenster]

My shed is built just like that, but way smaller (like 12 X 3 ) I screwed my panels right into the 2x rafters, although I had to nail in a few supports here and there (this shed build was no framing feat, I kinda just wung it)

Mine will be hidden back in the woods. It doesn't have to be too pretty.

People will likely tell you not to run the panels E/W, but mine are, and they haven't leaked yet. If you put the higher panel above the lower one (in terms of the overlap), its seems like its less likely to leak to me, water aint going back up the roof. I did run a bed of silicone along the seam for extra insurance

The roof will be flat except for a very slight slant toward one end of the 16 foot run. I'll overlap to protect it from rain being driven from the west. We don't get much weather coming out of the east and that sides the most protected by the woods, too. Roger that, on the caulking.

In terms of screws, I ponied up for the ones specifically for this application They're self-tapping, and have a rubber gasket/washer to keep things water tight. I think Id go that route rather than deck screws. If only becuase pre-drilling all those holes is gonna be a PITA

I think I'm sold on that. No pre-drilling! Why screw everything twice, right? I want to make this as inexpensive and no-labor intensive as possible. Are the screws you used phillips head or hex head? Seems like self tapping hex head would be the way go.

 

[Kenster]

Looks good. You can cut the metal roofing with a carpet/utility knife (I mean it). You simply score the metal with the knife (either side) and the sheet will rip on this score. I didn't believe it until I saw an Amish crew doing it this way, evening ripping 24-ft sheets lengthwise without problems.

Well, who would have thought?

 

[Lumber-Jack]

Get a metal cutting blade for your circular saw, you'll save yourself some aggravation.
Self tapping screws will work, but they can also be a pain to work with (especially with thicker gauge metal), much easier to pre-drill the holes.

 

[rwilly]

Use your typical saw blade, but install it backwards. Much easier for cutting the metal.

 

[begreen]

Our shed has a simple corrugated metal roof with no underlayment. It is attached with gasketed hex head screws made for this purpose. No issue so far after 5 years.I'm planning on adding an equipment bay this year to house the splitter and mower.

 

[bigbarf48]

Ah okay, I was envisionig the panels E/W and the slant N/S, thats how mine is

The screws were 1/4 hex heads, and I think theyre way easier to use than standard deck screws. Also consider that a normal screw doesnt have the little gasket thing

 

[gzecc]

I know that would be the best way but this really has to be done on the cheap. I'm going to have enough joists that it all should be plenty stable.

Guess I'm used to snow loads. Don't you get heavy winds?

 

[Boil&Toil]

You can certainly screw metal directly to purlins, so long as the purlin spacing is not too short for the metal to support itself, and you take care to walk only where the purlins are when you are building it. The correct hex-head with-washer roofing screws and a magnetic hex-head driver are well worth it - I used the version that is not self-drilling, and predrilled holes for them. That was on the shop, and is still good 11 years later (screw-down agricultural metal, not standing seam.)

I'm a bit dubious about 2x4's for joists if they are supposed to hold up a full stack of firewood over a 12 foot span...Perhaps you have unstated additional support so they are only spanning 4 feet or so?

If you run this with very little slope on the roof, you will very probably have leaks - you are not forming up new standing seams, and an overlap joint where water has little incentive to leave will eventually leak, IME - especially when run between purlins, so the lapped area has nothing to hold it together between purlins. It would be a good idea to have the higher end 3-4 feet higher than the shorter end to ensure positive drainage over 16 feet of roof. Flatter roofs are harder to keep dry. For using this material the way you intend to a roof that sloped both ways would be best, so the overlaps between sheets could have a positive drainage direction side-to side, as well as the end to end drainage.

Butyl rubber (if you can find it) is better than silicone for sealant, as it never really "dries" - silicone, once cured, can peel.

 

[Adios Pantalones]

One of the beauties of metal is that it sheds snow and ice. If you get that where you are, then reconsider going E/W.

edit- leaves, pine needles, and even dirt may accumulate if you have E/W ridges as well. I have N/S and I even get it (but sliding ice scrubs it out for me)

 

[Kenster]

Guess I'm used to snow loads. Don't you get heavy winds?

No worries on snow here in southeast Texas. Winds can be pretty fierce but are hardly felt back in the woods where the shed will be. I've had a large Logi-tech shed (sort of tarp roof and walls over pipe framing) back there for years with no wind issues at all. This metal roof will be pretty heavy.

 

[NRGarrott]

Kenster, you need to read what boil&toil wrote. Then read it 3 more times. He is dead right, and his advice will make the difference between a shed you tear down in 10 years, and one your grand kids will put a new roof on.

Also boil&toil he meant rafters, not joists. I imagine it is a dirt floor.

 

[Kenster]

One of the beauties of metal is that it sheds snow and ice. If you get that where you are, then reconsider going E/W.

edit- leaves, pine needles, and even dirt may accumulate if you have E/W ridges as well. I have N/S and I even get it (but sliding ice scrubs it out for me)

First off, I want to clarify the meaning of East/West and North/South. Just as we define these orientations when we are referring to laying firewood in our stoves, we would be looking 'north' when we are facing the front of the shed (stove.) West would be to our left and East to our right. The front of the shed, therefore is the north wall, the back wall is the south wall. Agreed?

Okay, Remember that the slope of the roof will be in the same direction as the ridges/seams. That is, East/West. I will probably give the roof a slight slope toward the East.

I don't see why the orientation would have any effect on accumulation of leaves and needles. If it becomes a problem I can take my gas powered blower and there and clean it up in a jiffy.

 

[Kenster]

Kenster, you need to read what boil&toil wrote. Then read it 3 more times. He is dead right, and his advice will make the difference between a shed you tear down in 10 years, and one your grand kids will put a new roof on.

Also boil&toil he meant rafters, not joists. I imagine it is a dirt floor.

Rafters, yes. Dirt floor, yes.

While the roof panels and the front and back wall headers are 16 feet, I am going to place the corner posts one foot in, allowing for a one foot overhang on the East and West Ends. This leaves 14 feet. The center post will be at 7 feet. Total of 10 rafters including a double one in the center at the center posts. Four spans spread out over seven feet means that the rafters will be set on 21 inch centers. I also will be putting in 2x4 cross pieces between the rafters, probably three in each span. It should be very solid.

 

[NRGarrott]

The cross pieces are called purloins, traditionally they are made out of 1x4's. No need for a 2x4.

 

[Kenster]

Okay, picture this shed with only two sections and the roof sloping from left to right instead of front to back. This is kinda what I'm shooting for. Again, the reason it would slope left to right (east/west) is because of the existing standing seams on these recycled roofing panels.

 

[Kenster]

The cross pieces are called purloins, traditionally they are made out of 1x4's. No need for a 2x4.

But I have a ton of 2x4 scraps on hand. (i.e NO COST!) They were the crating materials for the new roofing panels when they reroofed our house. They are all 22 inches. A quick touch of the chop saw and I'm in business.

 

[Adios Pantalones]

First off, I want to clarify the meaning of East/West and North/South. Just as we define these orientations when we are referring to laying firewood in our stoves, we would be looking 'north' when we are facing the front of the shed (stove.) West would be to our left and East to our right. The front of the shed, therefore is the north wall, the back wall is the south wall. Agreed?

Okay, Remember that the slope of the roof will be in the same direction as the ridges/seams. That is, East/West. I will probably give the roof a slight slope toward the East.

I don't see why the orientation would have any effect on accumulation of leaves and needles. If it becomes a problem I can take my gas powered blower and there and clean it up in a jiffy.

Sorry, I thought you meant going sideways, as it is when we say that a stove is loaded E/W. I'm glad I didn't call you an idiot over it

 

[Kenster]

It's getting even better. I found three 12 foot long 2x6 PT boards in my wood pile. And my neighbor just gave me 10 more. So, I will use 2x6s for rafters instead of 2x4s. Free wood! Why not. Makes a scroungers heart beat a little faster. And saved me about $100 at the lumber yard.