It seems to me like the slaters have used a too small countersink hole for the head of the nail,
I thought the head of the nail was supposed to sit in the countersunk hole, so that the nail head wont rub the slate above it. What they've done seems to just weaken the slate.
[g]
Possibly. It is difficult to tell from the photograph. It looks to me as though someone gave the tile a cursory wave in front of a countersink at an odd angle. The installer noticed and to avoid damaging the slate did not drive the nail home!
If the photo is typical, its a badly done job in my opinion. I used copper clouts (I not sure from the photo if thats what is in use here) which are soft enough that you punch the head down into the "countersink" using a drift (normally they are punched rather than drilled which produces a naturally countersink). This way it stops them rubbing the slates above with the slight movements in the wind, and wearing holes. Have a read of:
You normally have the wide head copper retaining clips to prevent this. They look a bit like a clout nail with a thin shaft and no point. The shaft goes through a hole in the bottom middle of the slate and the top is folded over, while the "head" is trapped behind the two lower slates with the shaft poking through the gap between them. That means the bottom of the slate is unable to lift.
I thought the holes were made by just whacking with a slate hammer, and I can't see why countersinking would be necessary with roofing nails
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D\
=A0 =A0 =A0 =A0|
=A0 =A0 =A0 =A0|
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D/
John, the method you described above is not the way roof slates are fix on a re slating job. The statement you describe is for replacing a single slate on a repair.
The slates are holed from the backside to a gauge formula "1/2 the length of the slate + 1/2 the lap + 1/2" This is called waist nailing. The batten gauge formula =93 deduct the lap off the length of the slate and then half the rest.
George is there any chance of a better photo. From what I see is, Welsh purple slates with a broken top corner, the slates look as if they are some form of head nailing or the battens gauge doesn't look as if its been set out for the size of the slates, the nails should be either copper or aluminium, I cant make out with the slates have been holed with a countersink or wither its shadow from the head of the nail. If there is a countersink the nails should be flush not standing proud. What=92s the underlay folded back for ?
unless it's the top slate at the ridge, which it looks like it is, in which case the ridge tile covers the slate, and the nail.
To the OP: don't panic -nails don't 'rub' and if i'm correct in that this is the top slate, it's probable that the nails were left protruding deliberatley
They would have to be pretty big ridge tiles for the nail and batten to be covered in that photo. If they aren't covered you risk them being flipped up and broken off, a very common failure mode around my Victorian neighborhood is the slate just below the ridge tiles snapping. Have a read of:
Care to explain the photo in:
yes it is the top slate.
According to the Slating Bible book, slates do move a bit, they are hanging on the nails, the nails shouldnt protrude, the countersink is made with a special tool, or by bashing from the other side.
[g]
I have seen it done quite commonly on initial slating as well (in this area anyway). In fact our roof has the bottom fastenings on all the tiles.
Yup, I would guess ours are nailed similar to that, but with the extra copper fixing as well.
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D\
=A0 =A0 =A0 =A0|
=A0 =A0 =A0 =A0|
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D/- Hide quoted text -
There is a differance between natural slate fixing and fiber cement slates, the latter doe's have a copper disc rivet in the tail. In Europe they do use hooks to fix both types of slates. The hook method is not common in the UK.
Ours are fibre cement imitation slates, nailed at the top (ish), and with the retaining rivet at the bottom (on most of them - one bit that was slated later appears to have been done without them)
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D\
=A0 =A0 =A0 =A0|
=A0 =A0 =A0 =A0|
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D/
They may lift a bit when new but as they age they get hard as the cement in them sets. Note to worry about other than there will be no manufactures guarantee do to no rivets.
I have a couple of broken or slipped ones to replace in the summer, so I will probably add the missing rivets to any that need them anyway since we get some fairly strong winds here.
Yes, they showed me yesterday that though the countersink hole is smaller than the head, the nail sits perfectly in it.
[g]HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.