What goes under my metal roof? OSB/membrane? Simple lean to shelter build

[nuzuki]

Hi all,

Im looking to build a simple lean too shelter coming off an existing agricultural building. I wanted to put down osb, then line it with plastic sheet then put metal box profile sheets over the top. Is this the correct method or am I missing something? Do I need to sheet beneath the OSB also or do I need sarkit breathable membrane rather than plastic sheet?

Thanks

 

[noseall]

All depends what the 'shelter' is actually doing and how it is constructed - i.e. is it open or enclosed? Heated or not?

 

[nuzuki]

Closed but not heated. It will have a vented walkway. I'm just trying to cut down on the condensation which is inevitable when having a metal roof. As long as all the fixings go into through the osb and into the beams I would of thought plastic sheet is fine no?

 

[noseall]

If you are that bothered, just buy the insulated metal sheets. Save all that faff and no condensation.

 

[nuzuki]

Hi all,
I posted this question previously in the building section but didnt recieve any clear answers. Im putting a metal roof on a simple lean to shelter. I just wanted to know what is considered the correct build up. From bottom upwards;- Is it Plastic sheet, battens, OSB, breathable sheet, then metal roof?
Or... Would OSB, plastic sheet, metal sheet be good enough? Or instead of the plastic sheet do I need to have a breathable membrane like sarkit.

Thanks for any pointers

 

[Leofric]

If it is just a 'simple lean to shelter' wouldn't it just be say Plastisol coated corrugated metal sheeting on structural supports as necessary

 

[nuzuki]

Ok simple ish

 

[Leofric]

I posted this question previously in the building section but didnt recieve any clear answers.

Ok simple ish

I think you need to say what it is exactly you are proposing to build if you want clear answers - does it have walls , if so, do you want it to be insulated and then will it be heated, what is the proposed use of the 'shelter'

 

[nuzuki]

Im proposing to build a lean to shelter (15m by 3.6m). It will have featheredge cladded sides all sheeted and possibly a bit of insulation in the future if I have some leftover from a job. The roof will be boarded out with OSB then box profile metal roof sheets. I just wanted to know if I put a sheet under and/or over the top of the OSB and if so which type of sheet, breathable or non breathable?

It will be used to store all sorts of garden junk and building materials so nothing important but stuff I dont want ruined by being right in the elements.

Thanks

 

[nuzuki]

https://www.diynot.com/diy/threads/metal-sheet-roofing-query.282830/#post-2053568

Ok found what I needed on the search. I'm not going to insulate the roof but it gives me a rough idea of the order.