Metal roofing / Purlin question

[jeffg]

I just got this picture from a fabricator that I contracted to build a couple of portable horse shelters for our big dry lot. Each shelter is 10' deep x 20' wide.

Is it just me, or are the purlins for this roof running the wrong direction? Shouldnt they be perpendicular to the roof panels? I have already asked the fabricator, but I havent gotten an answer back. I thought I would double check here. I have never seen roofing done this way.

They are scheduled to deliver the shelters tomorrow morning. Should I stop them before they arrive?

 

[jh87]

Definitely seems wrong to me. Here’s a link to one company’s screw pattern for metal roofing:

Metal roofing screw pattern

I don’t see how you can achieve the proper pattern the way they’re built currently.

 

[readhead]

Is this something they have been building and delivering for a long time? Why were you attracted to the product?
It actually isn’t an unusual design. I have seen similar structures around here. The metal is secured correctly to the pipe purlins. The difference you are not familiar with is the tube run under the laps.
You have committed to a sale and presumably you saw a sample before you made the deal. They have purchased material and provided labor to fulfill your commitment.
Express your concern and see what they say and then decide.

 

[CraigStu]

Seems weird to me also. They are counting on that metal panel to be pretty strong aren't they. I thought the purlins should run perpendicular to the roof panels every two feet.

 

[readhead]

They probably are using a tube under the laps and the sheets are flat against the purlins and screwed to the purlins. I’ve seen it before and it uses less expensive material. It is a very light duty structure that is usually staked down in a pasture to provide shade.

 

[Hank11]

If the purlins are located at each seam of the roofing metal then its gonna work out fine. There is more area for screws which might be important in a windy location. The whole seam can be stitched down.

 

[brownbagg]

no they are correct, purlin goes the opposite of sheet roofing, you got screw into the purlin,

 

[Max78]

For a light duty shade I would say its fine. The metal panels are not being used as a structural membrane like steel buildings so I wouldn't over think it.

If it survives the 50mph trip I would say you are good for at least 50mph winds no?

 

[billconner]

no they are correct, purlin goes the opposite of sheet roofing, you got screw into the purlin,

I agree with your post but looked to me the members parallel with roofing were used, not the lower members perpendicular.

 

[brownbagg]

i see what you saying now, I didnt look hard because i thought they was using actual purlln and not home made ****.

 

[Uncle murph]

I just got this picture from a fabricator that I contracted to build a couple of portable horse shelters for our big dry lot. Each shelter is 10' deep x 20' wide.

Is it just me, or are the purlins for this roof running the wrong direction? Shouldnt they be perpendicular to the roof panels? I have already asked the fabricator, but I havent gotten an answer back. I thought I would double check here. I have never seen roofing done this way.

They are scheduled to deliver the shelters tomorrow morning. Should I stop them before they arrive?

I’ve never built a roof I wouldn’t walk on and I definitely would not walk on that! I’ve seen sturdier umbrellas.

 

[billconner]

The photo and lighting in it may be misleading. Are the parallel lines actually just overlaps of translucent roofing, and the roof is attached to the perpendiculars? Hard to tell but can't help but think something is not as it appears.

 

[jeffg]

So I got to see the structure first hand.

The roof is made of 26ga white steel panels.

The roof is attached to 1x3 steel tubes at each overlap. There are several screws running down the length of each overlap.
The roof is also attached at each end of the roof panel. I guess I could call it perimeter attachment?

The rectangular tubes sit on top of the pipe, so there is a 1" gap between the middle of the roof panel and the cross pipes.

I am comtemplating inserting a 1" piece of material in between the pipe and the roofing panels. If I did, should I add more screens at each pipe?