Advice on Extending Shed Roof

[Kelly in tx]

I park four old tractors under a lean-to or shed roof of about 15' by 40'. I park the tractors side by side so front to back of each tractor uses the 15' space. I want that roof to be longer to better protect the tractors from sun and rain. The rafters are 6 C purlins. The edge is 4 C purlins. The roof is corrugated galvalume. I want to extend the roof by two feet. I intend to just remove the last row of sheet metal screws, tuck the new corrugated galvalume under it and replace the screws.
The bottom of the 4 C purlin clears the exhausts of my old tractors by about 4. The parking area is dirt (gravel/caliche), not concrete. The ground slopes downward away from the parking area.
I can: 1) put on 6 C purlin and extend the roof flat (I'll have easy exhausts clearance) or
2) put the 6 C purlin at the same angle as the rafters (I might have to remove a tiny bit of ground sloping away from the parking area.
What would you do?

 

[Janicholson]

Texas has been known to have a few wind gusts from off shore and tornados. I would not do what you intend. I might put a canvas drape down in front off the existing edge, to allow entry/exit. Adding unsupported roof . or flat sheet would not be a first choice. Jim

 

[Kelly in tx]

Yup, that's something to think about. There is a pretty good bunch of trees near the shed roof to break the wind and I'm thinking that if a wind catches the extension, it might take the whole roof but I doubt it and if it does, my thinking is it won't be too hard to replace that part. Maybe I'll be proven wrong. Thanks for the advice Jim. kelly

 

[tomturkey]

Where are the support posts for your shed roof. Do the 6 rafters set on the 4, or is there a header under the 6 rafters and the edge of the roof is cantilevered out, and the 4 is a facia support for the edge of the roof. I think I need more info. maybe its just me. gobble

 

[Geo-TH,In]

Advice on Extending Shed Roof.

I have no choice if I want to build anything.

First, I would have to get a building permit.

Second the board of health would tell me if I can build it.
No buildings in a flood plain.

Then, the building inspector will tell me how he wants it built.

After many hurricanes in Florida, people can no longer do what you want to do. All extending roofs must be self supporting. You can just attach it to an existing building.
All improvement plans drawn up by a building engineer.
Then the building inspector will make sure the construction follows building plans.

If I didn't have an inspector telling me what to do, I would put the sheet metal under the existing roof, extend the existing rafters. Then put posts the same spacing as pole barn. Build the new header the same way the pole barn was built..

The new construction would be the same as the original pole barn.

 

[Mark Poss]

If you have enough room for tractors why not put a wall up to protect from sun and rain?

 

[caterpillar guy]

I would just put an extension piece on the side of the current rafter then put a new roof board on the end to hold the tin screws then if worried about blowing off just put a brace from pole to end of new extension to support it more. I'm guessing you are driving the tractor in and out under the eve of the roof. If they were backed in from the end you could close the eave up and no grading or extension needed.

 

[Stephen Newell]

You shouldn't make the roof completely flat. Where it's joined you will be eternally plagued with leakage if it's flat. It should have a minimum slope of an inch. Then where the sheets overlap do an overkill sealing it. If you have a torrential rain the water will run over the ridge and leak, especially if leaves or debris collect on the roof.

 

[Geo-TH,In]

If your existing pole bar has a 4/12 pitch and is 30 ft wide, check out the price of a 30 ft truss. Cut the truss in half.
Attach the rafter of the half truss to the existing rafter of the pole barn truss. Support the end of the half truss like it's supported inside the barn. Run a board horizontally to attach the lower half of the half truss. That board may be more than one, depending on the spacing of the poles..

 

[Bob Harvey]

Good thoughts, BUT, you cannot cut a truss and expect it to work as planned nor pass any kind of inspection. I once got ratted out by a next day fired employee who told an inspector that I had cut a truss (spanned a whole house, to allow for an attic access). When confronted by said inspector, I gave him the revised engineering drawing provided by the truss Co. Sometimes it better to keep your big yap shut.

 

[Geo-TH,In]

I thought I made it very clear in my post below.

Advice on Extending Shed Roof.

I have no choice if I want to build anything.

First, I would have to get a building permit.

Second the board of health would tell me if I can build it.
No buildings in a flood plain.

Then, the building inspector will tell me how he wants it built.

If I didn't have an inspector telling me what to do, I would put the sheet metal under the existing roof, extend the existing rafters. Then put posts the same spacing as pole barn. Build the new header the same way the pole barn was built..

And I added in another post splitting a truss.
This would be stronger than using a single 18 ft board for a rafter..

 

[Geo-TH,In]

You can buy what I called a half truss.
2 Miles N of Terre Haute North Menards store is a truss company owned by Menards.
I know the manager of that factory. He was a former student.
They can make any kind of truss you want..
I can't copy the truss design so I posted pics of trusses.
If you want a strong truss talk to the people at Menards.
Truss designs.

 

[caterpillar guy]

Geo not everybody lives in a communist state where if you mow the lawn you have to have a permit and pass an inspection afterwards. Some places don't even need a permit to build a building for farm use. Some don't even need a permit for other out buildings .

 

[RobCons]

I would look into a curtain. Nice canvas with metal hangers around a cable or bar so it could be slid open easily.

 

[DoubleO7]

Kelly says rafters are 6 C purlins as in steel with corrugated steel panels on top. With hat channels or similar between C purlins and roofing steel.
The 6 C purlins being 15/16 feet long

If that is the case, I would just extend the 6 inch purlins by screwing short lengths of new 6 inch purlin back to back to the existing purlins.

This post was edited by DoubleO7 on 09/25/2022 at 06:21 am.

 

[sandcastle1]

X2