Can't complain , it must be more than 25 years old.
Leaks due to the felt disappearing over the tacks holding down the bottom
layer of felt. What causes this and how to reduce the possibility when
re-felting?
Is thermal movement wearing away at the upper felt or local heating from the
sun and insufficient pea grit on top, or what - they're quite neat holes ?
When re-doing perhaps place a square of upholstery tape over each tack
before applying the top layer and tar or perhaps tacks pushed through rings
of cut-up bicycle inner tube for rubber washer below the tack heads and
above.?
For the moment temporarily patched with hot-melt glue and patches of felt
with extra heating from a hot air gun , well tar and hotmelt seem to melt at
about the same temperature.

---
A pictorial appreciation of the work of local Southampton architect Herbert
Collins
http://www.diversed.fsnet.co.uk/hc.htm
and buried in the file, linked to at the end of that file, some pics of
mathematical tiles and Fareham/Bishop's Waltham terra cotta chimney pots

N Cook wrote:
Can't complain , it must be more than 25 years old.
Leaks due to the felt disappearing over the tacks holding down the
bottom layer of felt. What causes this and how to reduce the
possibility when re-felting?
Is thermal movement wearing away at the upper felt or local heating
from the sun and insufficient pea grit on top, or what - they're
quite neat holes ? When re-doing perhaps place a square of upholstery
tape over each tack before applying the top layer and tar or perhaps
tacks pushed through rings of cut-up bicycle inner tube for rubber
washer below the tack heads and above.?
For the moment temporarily patched with hot-melt glue and patches of
felt with extra heating from a hot air gun , well tar and hotmelt
seem to melt at about the same temperature.


This post doesn't make much sense to me, 'tacks in the bottom layer of
felt'? - if it's a flat roof, then the felt isn't tacked at all, it's laid
into hot bitumen as are the layers over the top, the only time tacks are
used is at the edges where it meets the fascia boards...am I missing
something here?

Phil L wrote in message
.uk...
N Cook wrote:
Can't complain , it must be more than 25 years old.
Leaks due to the felt disappearing over the tacks holding down the
bottom layer of felt. What causes this and how to reduce the
possibility when re-felting?
Is thermal movement wearing away at the upper felt or local heating
from the sun and insufficient pea grit on top, or what - they're
quite neat holes ? When re-doing perhaps place a square of upholstery
tape over each tack before applying the top layer and tar or perhaps
tacks pushed through rings of cut-up bicycle inner tube for rubber
washer below the tack heads and above.?
For the moment temporarily patched with hot-melt glue and patches of
felt with extra heating from a hot air gun , well tar and hotmelt
seem to melt at about the same temperature.


This post doesn't make much sense to me, 'tacks in the bottom layer of
felt'? - if it's a flat roof, then the felt isn't tacked at all, it's laid
into hot bitumen as are the layers over the top, the only time tacks are
used is at the edges where it meets the fascia boards...am I missing
something here?



Perhaps roof is overstating it, 18 inch wide flat roof over a bay window.
There's definitely tacks, 6 eruptions , so far, over felting tacks, central
area, no problems at the edges.


---
A pictorial appreciation of the work of local Southampton architect Herbert
Collins
http://www.diversed.fsnet.co.uk/hc.htm
and buried in the file, linked to at the end of that file, some pics of
mathematical tiles and Fareham/Bishop's Waltham terra cotta chimney pots

N Cook wrote:
Phil L wrote in message
.uk...
N Cook wrote:
Can't complain , it must be more than 25 years old.
Leaks due to the felt disappearing over the tacks holding down the
bottom layer of felt. What causes this and how to reduce the
possibility when re-felting?
Is thermal movement wearing away at the upper felt or local heating
from the sun and insufficient pea grit on top, or what - they're
quite neat holes ? When re-doing perhaps place a square of
upholstery tape over each tack before applying the top layer and
tar or perhaps tacks pushed through rings of cut-up bicycle inner
tube for rubber washer below the tack heads and above.?
For the moment temporarily patched with hot-melt glue and patches of
felt with extra heating from a hot air gun , well tar and hotmelt
seem to melt at about the same temperature.


This post doesn't make much sense to me, 'tacks in the bottom layer
of felt'? - if it's a flat roof, then the felt isn't tacked at all,
it's laid into hot bitumen as are the layers over the top, the only
time tacks are used is at the edges where it meets the fascia
boards...am I missing something here?



Perhaps roof is overstating it, 18 inch wide flat roof over a bay
window. There's definitely tacks, 6 eruptions , so far, over felting
tacks, central area, no problems at the edges.


Either way it shouldn't have tacks in it at all, it should have been done
with hot bitumen and had 2 or 3 layers of felt laid into it.
If you put it back the way it was, it will leak again, tacks are not meant
to be used in this way, how long has it been like this?

Phil L wrote in message
. uk...
N Cook wrote:
Phil L wrote in message
.uk...
N Cook wrote:
Can't complain , it must be more than 25 years old.
Leaks due to the felt disappearing over the tacks holding down the
bottom layer of felt. What causes this and how to reduce the
possibility when re-felting?
Is thermal movement wearing away at the upper felt or local heating
from the sun and insufficient pea grit on top, or what - they're
quite neat holes ? When re-doing perhaps place a square of
upholstery tape over each tack before applying the top layer and
tar or perhaps tacks pushed through rings of cut-up bicycle inner
tube for rubber washer below the tack heads and above.?
For the moment temporarily patched with hot-melt glue and patches of
felt with extra heating from a hot air gun , well tar and hotmelt
seem to melt at about the same temperature.


This post doesn't make much sense to me, 'tacks in the bottom layer
of felt'? - if it's a flat roof, then the felt isn't tacked at all,
it's laid into hot bitumen as are the layers over the top, the only
time tacks are used is at the edges where it meets the fascia
boards...am I missing something here?



Perhaps roof is overstating it, 18 inch wide flat roof over a bay
window. There's definitely tacks, 6 eruptions , so far, over felting
tacks, central area, no problems at the edges.


Either way it shouldn't have tacks in it at all, it should have been done
with hot bitumen and had 2 or 3 layers of felt laid into it.
If you put it back the way it was, it will leak again, tacks are not meant
to be used in this way, how long has it been like this?



At least 25 years.

Surely roofing felt has to be tacked down or any half decent wind in the
wrong direction round a corner or whatever, generating negative pressure,
would suck the felt off the roof.


---
A pictorial appreciation of the work of local Southampton architect Herbert
Collins
http://www.diversed.fsnet.co.uk/hc.htm
and buried in the file, linked to at the end of that file, some pics of
mathematical tiles and Fareham/Bishop's Waltham terra cotta chimney pots

N Cook wrote:

Can't complain , it must be more than 25 years old.
Leaks due to the felt disappearing over the tacks holding down the bottom
layer of felt. What causes this and how to reduce the possibility when
re-felting?
Is thermal movement wearing away at the upper felt or local heating from the
sun and insufficient pea grit on top, or what - they're quite neat holes ?
When re-doing perhaps place a square of upholstery tape over each tack
before applying the top layer and tar or perhaps tacks pushed through rings
of cut-up bicycle inner tube for rubber washer below the tack heads and
above.?
For the moment temporarily patched with hot-melt glue and patches of felt
with extra heating from a hot air gun , well tar and hotmelt seem to melt at
about the same temperature.

It sounds like it has been felted in the same way you would do a pitched
roof (i.e. shed etc), with a nail prep layer (hessian reinforced felt),
then bonded middle and top coats.

In your case, someone may have been cutting costs and missed out the
middle coat of under felt!

--
Cheers,

John.

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Apparently in the Welsh valleys a "foof" is what little girls call their
genitalia.

--
Skipweasel
Pay no attention to that man behind the curtain.