Metal roofing

[clake4341]

I am nearly finished my roof sheathing and plan on using metal over top. The bldg is 24 x 20 ft with a second storey. I will be using about 20 sheets of metal (36" x 18Ft) I was hoping I could get some advise on the spacing. I was planning on using 2x4's
spaced 24" In other words 10 rows of 2x4's the length of the house (28' ) per side so I am looking at about 560 linear feet of 2x4. My question is is this standard or is it over kill. I have seen houses with the screws spaced about 6". I was also thinking of using 1.5 rigid insulation, but I am thinking maybe the price of the insulation would be too expensive. Can the metal be put right on the sheathing or is the 2x4 backing better?? Anyone have any thoughts on this

[MountainDon]

I now have two metal roofs installed over OSB sheathing. The one roof has a synthetic wrap, Titanium UDL, and the other uses #30 felt over the sheathing. The metal is screwed on top of that. That seems to be typical for metal roofs around here.

Vertically up and down the panels, the screws are spaced about 32 inches apart. One screw per "flat" between the ribs. Where panels over lap they used self tapping metal screws about every 12 inches.

I never looked into insulation at that point as the buildings are constructed with conventional attics.

I would think using the 2x4's is overkill. Some roofs are done with metal over purlins like that, but that's without the sheathing. That also introduces its own roof insulation problems/solutions.

[glenn kangiser]

Usually either one or the other, but felt under the metal, then go with standard fiberglass insulation for cheaper.  

[Okie_Bob]

I agree with both Don and Glenn. 2 X 4 is definate overkill. I used 1 X 4 on a garage and I used plywood under metal on my house. Both work well but, I'd go with the plywood sheathing. Insulation is a whold other topic. I'm a very happy Isyonene customer and the longer
I'm in my house the more I like it. My cooling bills this summer have been much less than expected. Course I guess that depends on where you live.
Okie Bob

[rakuz66]

Guess I'm going with 2x4 purlins then. 

[PEG688]

Guess I'm going with 2x4 purlins then. 

Rak I'd think you'd want minimum , 4x6 12"OC

[MountainDon]

You're too funny Paul.   

[glenn kangiser]