Got a bit of a leak in the roof of one my sheds. The roof is constructed
of box-profile sheets and there are some small leaks around some of the
fixing screws.

The real problem is that the slope on the roof is probably too shallow
for these type of sheets, but I can't do much about that at the moment.
A few weeks back I replaced many of the screws - with the correct type,
new washers, etc - but that hasn't solved the problem. I'm thinking of
covering the offending screws with some kind of trowel-on mastic but I'm
not sure which is the best type to use. Any recommendations?

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On 30/12/2013 13:17, Farmer Giles wrote:
Got a bit of a leak in the roof of one my sheds. The roof is constructed
of box-profile sheets and there are some small leaks around some of the
fixing screws.

The real problem is that the slope on the roof is probably too shallow
for these type of sheets, but I can't do much about that at the moment.
A few weeks back I replaced many of the screws - with the correct type,
new washers, etc - but that hasn't solved the problem. I'm thinking of
covering the offending screws with some kind of trowel-on mastic but I'm
not sure which is the best type to use. Any recommendations?

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I'd be inclined to use 50 mm lengths of 50 mm Sylglas tape

On 30/12/2013 13:39, newshound wrote:
On 30/12/2013 13:17, Farmer Giles wrote:
Got a bit of a leak in the roof of one my sheds. The roof is constructed
of box-profile sheets and there are some small leaks around some of the
fixing screws.

The real problem is that the slope on the roof is probably too shallow
for these type of sheets, but I can't do much about that at the moment.
A few weeks back I replaced many of the screws - with the correct type,
new washers, etc - but that hasn't solved the problem. I'm thinking of
covering the offending screws with some kind of trowel-on mastic but I'm
not sure which is the best type to use. Any recommendations?

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I'd be inclined to use 50 mm lengths of 50 mm Sylglas tape

I mean this one

http://www.amazon.co.uk/Sylglas-Wate...s=sylglas+tape

given that they now do all sorts!

On 30/12/2013 13:41, newshound wrote:
On 30/12/2013 13:39, newshound wrote:
On 30/12/2013 13:17, Farmer Giles wrote:
Got a bit of a leak in the roof of one my sheds. The roof is constructed
of box-profile sheets and there are some small leaks around some of the
fixing screws.

The real problem is that the slope on the roof is probably too shallow
for these type of sheets, but I can't do much about that at the moment.
A few weeks back I replaced many of the screws - with the correct type,
new washers, etc - but that hasn't solved the problem. I'm thinking of
covering the offending screws with some kind of trowel-on mastic but I'm
not sure which is the best type to use. Any recommendations?

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I'd be inclined to use 50 mm lengths of 50 mm Sylglas tape

I mean this one

http://www.amazon.co.uk/Sylglas-Wate...s=sylglas+tape


given that they now do all sorts!

Thank you. I'll have a look at that stuff.

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In article , Farmer
Giles writes
On 30/12/2013 13:41, newshound wrote:

I'd be inclined to use 50 mm lengths of 50 mm Sylglas tape

I mean this one

http://www.amazon.co.uk/Sylglas-Wate...p/B007SLAI9C/r
ef=sr_1_11?ie=UTF8&qid=1388410785&sr=8-11&keywords=sylglas+tape


given that they now do all sorts!

Thank you. I'll have a look at that stuff.

It is v good for this kind of job if a bit messy to use and perhaps a
tad unsightly but fine for a shed I'd imagine. Gloves and expendable
scissors essential.

On older sheets, it's not uncommon for the coating layer
(paint/powder/polyester/whatever) to detach from the sheet metal when
the screw is tightened which can lead to a drip leak behind the paint.

The tape over the top should solve that.

I was going to suggest Plumbers' Gold sealant as an alternative, evilly
sticky and can be applied to wet surfaces but Sylglas may well be better
(longer lasting).

http://www.toolstation.com/shop/p61679
--
fred
it's a ba-na-na . . . .

Farmer Giles wrote:

Got a bit of a leak in the roof of one my sheds. The roof is constructed
of box-profile sheets and there are some small leaks around some of the
fixing screws.

Presume the screws are on the ridges, rather than in the valleys?

On 30/12/2013 13:44, Andy Burns wrote:
Farmer Giles wrote:

Got a bit of a leak in the roof of one my sheds. The roof is constructed
of box-profile sheets and there are some small leaks around some of the
fixing screws.

Presume the screws are on the ridges, rather than in the valleys?



With box-profile sheets the screws can't be put on the ridges.

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On 30/12/2013 13:47, Farmer Giles wrote:
On 30/12/2013 13:44, Andy Burns wrote:
Farmer Giles wrote:

Got a bit of a leak in the roof of one my sheds. The roof is constructed
of box-profile sheets and there are some small leaks around some of the
fixing screws.

Presume the screws are on the ridges, rather than in the valleys?



With box-profile sheets the screws can't be put on the ridges.

They can be if you fit spacers.
It really needs two people to do it unless you have very long arms.

On 30/12/2013 16:44, dennis@home wrote:
On 30/12/2013 13:47, Farmer Giles wrote:
On 30/12/2013 13:44, Andy Burns wrote:
Farmer Giles wrote:

Got a bit of a leak in the roof of one my sheds. The roof is
constructed
of box-profile sheets and there are some small leaks around some of the
fixing screws.

Presume the screws are on the ridges, rather than in the valleys?



With box-profile sheets the screws can't be put on the ridges.

They can be if you fit spacers.
It really needs two people to do it unless you have very long arms.


I have never heard of, or seen, them being fitted that way but I suppose
it would work. Can't try it here though, because the screws are already
fitted in the flat area.

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In message , Andy
Burns writes
Farmer Giles wrote:

Got a bit of a leak in the roof of one my sheds. The roof is constructed
of box-profile sheets and there are some small leaks around some of the
fixing screws.

Presume the screws are on the ridges, rather than in the valleys?

Box profile is normally secured in the valleys. (sealing washer under
the screw head).

You should also use butyl tape under the lap ridge and *stitchers* every
450mm.

Agricultural roof slope could be 15deg.

--
Tim Lamb

In article ,
Farmer Giles wrote:
Got a bit of a leak in the roof of one my sheds. The roof is constructed
of box-profile sheets and there are some small leaks around some of the
fixing screws.

The real problem is that the slope on the roof is probably too shallow
for these type of sheets, but I can't do much about that at the moment.
A few weeks back I replaced many of the screws - with the correct type,
new washers, etc - but that hasn't solved the problem. I'm thinking of
covering the offending screws with some kind of trowel-on mastic but I'm
not sure which is the best type to use. Any recommendations?

Wicks do a rather good non setting mastic which seems to stick to anything.
Specifically for roof repairs, etc. Not expensive, so worth a try.

--
*Microsoft broke Volkswagen's record: They only made 21.4 million bugs.

Dave Plowman London SW
To e-mail, change noise into sound.

"Farmer Giles" wrote in message
o.uk...
Got a bit of a leak in the roof of one my sheds. The roof is constructed
of box-profile sheets and there are some small leaks around some of the
fixing screws.

The real problem is that the slope on the roof is probably too shallow for
these type of sheets, but I can't do much about that at the moment. A few
weeks back I replaced many of the screws - with the correct type, new
washers, etc - but that hasn't solved the problem. I'm thinking of
covering the offending screws with some kind of trowel-on mastic but I'm
not sure which is the best type to use. Any recommendations?

---
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protection is active.
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I assume there were the soft waterproofing seals under the washers?
The most likely thing is that the sheets have rusted through.
Or the screws have not been put in square so leaving a gap under the washer.

I have never had these leak in the past except through rusting.
Are you certain it's the fixing points leaking and not rain blowing in or
similar?

On 30/12/2013 17:01, harryagain wrote:
"Farmer Giles" wrote in message
o.uk...
Got a bit of a leak in the roof of one my sheds. The roof is constructed
of box-profile sheets and there are some small leaks around some of the
fixing screws.

The real problem is that the slope on the roof is probably too shallow for
these type of sheets, but I can't do much about that at the moment. A few
weeks back I replaced many of the screws - with the correct type, new
washers, etc - but that hasn't solved the problem. I'm thinking of
covering the offending screws with some kind of trowel-on mastic but I'm
not sure which is the best type to use. Any recommendations?

---
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protection is active.
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I assume there were the soft waterproofing seals under the washers?

Yes.


The most likely thing is that the sheets have rusted through.
Or the screws have not been put in square so leaving a gap under the washer.

The sheets haven't rusted, and the screws are in square.


I have never had these leak in the past except through rusting.
Are you certain it's the fixing points leaking and not rain blowing in or
similar?


I have other sheds with the same roofs and they don't leak either. As I
said previously, the slope of this roof isn't really adequate and that
is the main reason for the problems. I have ordered some Sylglas tape,
and I will also get the Wickes stuff that was recommended, and try that
- trying a belt and braces approach!


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"Farmer Giles" wrote in message
o.uk...
Got a bit of a leak in the roof of one my sheds. The roof is constructed
of box-profile sheets and there are some small leaks around some of the
fixing screws.

The real problem is that the slope on the roof is probably too shallow for
these type of sheets, but I can't do much about that at the moment. A few
weeks back I replaced many of the screws - with the correct type, new
washers, etc - but that hasn't solved the problem. I'm thinking of
covering the offending screws with some kind of trowel-on mastic but I'm
not sure which is the best type to use. Any recommendations?

---
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protection is active.
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Just had a further thought about your roof.
If the fixing screws are overtightened, the "thread" in the wood can strip
and the screw neither fixes or makes a proper seal.

This can happen if a power screwdriver is used.
The problem is you then have a hole with a stripped thread.
Only solution (short of wallplug in hole) is a longer screw.
Wallplug in hole soon works loose BTW.

Leaks appear later not right away often.

Box profile roof can be really shallow slope. So long as water is not blown
back up under flashings or whatever.
Check this out. There are fixes for this if it is happening. Leaks only
appear in windy weather with this problem.

On 30/12/2013 17:56, harryagain wrote:
"Farmer Giles" wrote in message
o.uk...
Got a bit of a leak in the roof of one my sheds. The roof is constructed
of box-profile sheets and there are some small leaks around some of the
fixing screws.

The real problem is that the slope on the roof is probably too shallow for
these type of sheets, but I can't do much about that at the moment. A few
weeks back I replaced many of the screws - with the correct type, new
washers, etc - but that hasn't solved the problem. I'm thinking of
covering the offending screws with some kind of trowel-on mastic but I'm
not sure which is the best type to use. Any recommendations?

---
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protection is active.
http://www.avast.com


Just had a further thought about your roof.
If the fixing screws are overtightened, the "thread" in the wood can strip
and the screw neither fixes or makes a proper seal.

This can happen if a power screwdriver is used.
The problem is you then have a hole with a stripped thread.
Only solution (short of wallplug in hole) is a longer screw.
Wallplug in hole soon works loose BTW.

Leaks appear later not right away often.

Box profile roof can be really shallow slope. So long as water is not blown
back up under flashings or whatever.
Check this out. There are fixes for this if it is happening. Leaks only
appear in windy weather with this problem.



Thanks again for your further suggestions.

I don't think that the water is being blown back underneath - although
the problem is mainly along the first 2 feet or so from the edge. I
think your first suggestion may be nearer the mark, as I seem to recall
that getting a tight fix on some of the outer screws was quite
difficult. I think I'll still try the mastic/Sylgas over the screws
suggestion first.



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"Farmer Giles" wrote in message
o.uk...
On 30/12/2013 17:56, harryagain wrote:
"Farmer Giles" wrote in message
o.uk...
Got a bit of a leak in the roof of one my sheds. The roof is constructed
of box-profile sheets and there are some small leaks around some of the
fixing screws.

The real problem is that the slope on the roof is probably too shallow
for
these type of sheets, but I can't do much about that at the moment. A
few
weeks back I replaced many of the screws - with the correct type, new
washers, etc - but that hasn't solved the problem. I'm thinking of
covering the offending screws with some kind of trowel-on mastic but I'm
not sure which is the best type to use. Any recommendations?

---
This email is free from viruses and malware because avast! Antivirus
protection is active.
http://www.avast.com


Just had a further thought about your roof.
If the fixing screws are overtightened, the "thread" in the wood can
strip
and the screw neither fixes or makes a proper seal.

This can happen if a power screwdriver is used.
The problem is you then have a hole with a stripped thread.
Only solution (short of wallplug in hole) is a longer screw.
Wallplug in hole soon works loose BTW.

Leaks appear later not right away often.

Box profile roof can be really shallow slope. So long as water is not
blown
back up under flashings or whatever.
Check this out. There are fixes for this if it is happening. Leaks only
appear in windy weather with this problem.



Thanks again for your further suggestions.

I don't think that the water is being blown back underneath - although the
problem is mainly along the first 2 feet or so from the edge. I think your
first suggestion may be nearer the mark, as I seem to recall that getting
a tight fix on some of the outer screws was quite difficult. I think I'll
still try the mastic/Sylgas over the screws suggestion first.


I don't think mastic will work, have tried it myself.
You can use long round head screws the same diameter as the regular fixing
screw.
They will accept the washer/seals.

Or if the purlin is thin, nuts and bolts that fit the washer.

On 31/12/2013 08:14, harryagain wrote:
"Farmer Giles" wrote in message
o.uk...
On 30/12/2013 17:56, harryagain wrote:
"Farmer Giles" wrote in message
o.uk...
Got a bit of a leak in the roof of one my sheds. The roof is constructed
of box-profile sheets and there are some small leaks around some of the
fixing screws.

The real problem is that the slope on the roof is probably too shallow
for
these type of sheets, but I can't do much about that at the moment. A
few
weeks back I replaced many of the screws - with the correct type, new
washers, etc - but that hasn't solved the problem. I'm thinking of
covering the offending screws with some kind of trowel-on mastic but I'm
not sure which is the best type to use. Any recommendations?

---
This email is free from viruses and malware because avast! Antivirus
protection is active.
http://www.avast.com


Just had a further thought about your roof.
If the fixing screws are overtightened, the "thread" in the wood can
strip
and the screw neither fixes or makes a proper seal.

This can happen if a power screwdriver is used.
The problem is you then have a hole with a stripped thread.
Only solution (short of wallplug in hole) is a longer screw.
Wallplug in hole soon works loose BTW.

Leaks appear later not right away often.

Box profile roof can be really shallow slope. So long as water is not
blown
back up under flashings or whatever.
Check this out. There are fixes for this if it is happening. Leaks only
appear in windy weather with this problem.



Thanks again for your further suggestions.

I don't think that the water is being blown back underneath - although the
problem is mainly along the first 2 feet or so from the edge. I think your
first suggestion may be nearer the mark, as I seem to recall that getting
a tight fix on some of the outer screws was quite difficult. I think I'll
still try the mastic/Sylgas over the screws suggestion first.


I don't think mastic will work, have tried it myself.
You can use long round head screws the same diameter as the regular fixing
screw.
They will accept the washer/seals.

Or if the purlin is thin, nuts and bolts that fit the washer.



Nuts and bolts sounds like a good idea where there is difficulty getting
a good fix, I think I'll give that a try. Many thanks.

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