The old relocation project of the guest house ended in dismantling and reassembling. The roof is made of tongue and groove boards (foot to ridge on 7 beams between the gables). Previously, the roof sheet (T20) was placed directly on the felt and screwed with farmer screws into the tongue and groove boards, probably into the beams as well. I have laid new underlay felt, but now everyone says I must lay battens first. The problem is that the sheet, which I plan to reuse, already has screw holes. What is the risk of screwing directly onto the underlay felt, and how can it be eliminated? Planning to use 35 mm farmer screws.
tar paper and then battens works well as I understand it.
On the garage and the storage shed, I screwed the sheet metal directly onto the tar paper. It was a year ago now, but I don't remember there being any risks with that? I discussed it with the metal guy I bought the sheet metal from, so I don't think there's any extra risk with it.
What is the difference between screwing the sheet metal through the tar paper compared to nailing the battens through the tar paper? A hole is a hole, right?
What is the difference between screwing the sheet metal through the tar paper compared to nailing the battens through the tar paper? A hole is a hole, right?
Member
· Norrbotten
· 3 390 posts
The difference as I see it is two things:
1) You get better ventilated space under the sheet with battens, which dries out any moisture that has entered more quickly.
2) There is a greater distance between the underlay and the sheet metal, increasing the chance that leakage in a screw hole can partially drain away on the tar paper.
ALL installation instructions I've seen for roof sheeting include battens of some kind, wood battens or metal battens. I would definitely install battens, counter battens, and purlins. On a small shed, this is neither a major expense nor much work, maybe an hour or so. I might also have tried to apply bitumen on the underside of the sheet where any larger damages/screw holes are found.
1) You get better ventilated space under the sheet with battens, which dries out any moisture that has entered more quickly.
2) There is a greater distance between the underlay and the sheet metal, increasing the chance that leakage in a screw hole can partially drain away on the tar paper.
ALL installation instructions I've seen for roof sheeting include battens of some kind, wood battens or metal battens. I would definitely install battens, counter battens, and purlins. On a small shed, this is neither a major expense nor much work, maybe an hour or so. I might also have tried to apply bitumen on the underside of the sheet where any larger damages/screw holes are found.
Thank you for all the answers. I feel that it should go well without läckt since the house is only used in the summer and there is no insulation. One problem was that there are already screw holes in the metal.
I also don't understand why a lot of nails would be safer than a few screws.
I also don't understand why a lot of nails would be safer than a few screws.