slate countersink size?
![george [dicegeorge]'s profile photo](http://lh3.googleusercontent.com/a-/ALV-UjVy3egmWxdo6kgdNwXDn-6EE54MDMuR9kO5wF-DhVhewlzxjNY=s40-c)
george [dicegeorge]
have used a too small countersink hole
for the head of the nail,
http://www.dicegeorge.com/psb/psimg/hfc-slate-countersink15022010679c.jpg
Am I right, or am I worrying unnecessarily?
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]
Clot
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!
Cod Roe
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:
http://www.traditionalroofing.com/downloads/TR5_hole_article.pdf
The battening also looks a bit odd, normally the holes are around a
third of the way down the slate, and the top of the slate rests against
a batten, it is nailed to another, and then some overlap with the slate
below. In your picture there is nothing to stop the wind catching the
slate, flipping it upwards, and then breaking it off.
John Rumm
> The battening also looks a bit odd, normally the holes are around a
> third of the way down the slate, and the top of the slate rests against
> a batten, it is nailed to another, and then some overlap with the slate
> below. In your picture there is nothing to stop the wind catching the
> slate, flipping it upwards, and then breaking it off.
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.
--
Cheers,
John.
/=================================================================\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\=================================================================/
Stuart Noble
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
Kipper at sea
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 “ deduct the lap off the length of the slate
and then half the rest.
Kipper at sea
wrote:
> It seems to me like the slaters
> have used a too small countersink hole
> for the head of the nail,
>
>
> Am I right, or am I worrying unnecessarily?
>
> 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]
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’s the underlay folded back for ?
Phil L
>
> The battening also looks a bit odd, normally the holes are around a
> third of the way down the slate, and the top of the slate rests
> against a batten, it is nailed to another, and then some overlap with
> the slate below. In your picture there is nothing to stop the wind
> catching the slate, flipping it upwards, and then breaking it off.
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
--
Phil L
RSRL Tipster Of The Year 2008
Cod Roe
> Cod Roe wrote:
>
>> The battening also looks a bit odd, normally the holes are around a
>> third of the way down the slate, and the top of the slate rests
>> against a batten, it is nailed to another, and then some overlap with
>> the slate below. In your picture there is nothing to stop the wind
>> catching the slate, flipping it upwards, and then breaking it off.
>
> 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.
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:
http://www.roofconsult.co.uk/articles/fixslate.htm
to see the double batten technique to prevent this problem.
>
> 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
Care to explain the photo in:
http://www.traditionalroofing.com/downloads/TR5_hole_article.pdf
and the pile of slates showing this in my garden that came off my roof?
Why would you leave the nail protruding deliberately? All it will do
is make the slate loose and more prone to be caught and broken by the wind.
george [dicegeorge]
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]
John Rumm
> On Feb 20, 12:04 am, John Rumm <see.my.signat...@nowhere.null> wrote:
>> Cod Roe wrote:
>>> The battening also looks a bit odd, normally the holes are around a
>>> third of the way down the slate, and the top of the slate rests against
>>> a batten, it is nailed to another, and then some overlap with the slate
>>> below. In your picture there is nothing to stop the wind catching the
>>> slate, flipping it upwards, and then breaking it off.
>> 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.
> 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.
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.
> 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 � deduct the lap off the length of the slate
> and then half the rest.
Yup, I would guess ours are nailed similar to that, but with the extra
copper fixing as well.
Kipper at sea
> Kipper at sea wrote:
> > On Feb 20, 12:04 am, John Rumm <see.my.signat...@nowhere.null> wrote:
> >> Cod Roe wrote:
> >>> The battening also looks a bit odd, normally the holes are around a
> >>> third of the way down the slate, and the top of the slate rests against
> >>> a batten, it is nailed to another, and then some overlap with the slate
> >>> below. In your picture there is nothing to stop the wind catching the
> >>> slate, flipping it upwards, and then breaking it off.
> >> 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.
> > 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.
>
> 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.
>
> > 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.
> > and then half the rest.
>
> Yup, I would guess ours are nailed similar to that, but with the extra
> copper fixing as well.
>
> --
> Cheers,
>
> John.
>
> /=================================================================\
> | Internode Ltd - http://www.internode.co.uk |
> |-----------------------------------------------------------------|
> | John Rumm - john(at)internode(dot)co(dot)uk |
>
> - Show 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.
John Rumm
> 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
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)
> Europe they do use hooks to fix both types of slates. The hook method
> is not common in the UK.
--
Kipper at sea
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.
John Rumm
> 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.
george [dicegeorge]
smaller than the head, the nail sits perfectly in it.
[g]