I'm sure this must be a regular chestnut on this forum, in which case
perhaps there are some useful sites and FAQs which people would be kind
enough to point me at.

I have a very large lounge, with a flat roof. It looks rather like it's an
extension to the main house, but is in fact part of the standard design and
the joists are properly linked in with the main roof. It's in effect a
bungalow with bedrooms within the roof space, with windows on the gable
ends, and from the 'spare' roof space on one side of the first floor I can
peep through and see above the lounge ceiling. Because the joists are the
same thickness as those in the main house, they are perhaps a little deeper
than you might expect in the circumstances - 9" in fact. The relevance of
this will become apparent later.

The main problem is that the roof is done in the traditional 'tar-and-felt'
method, and of course now that it's a few years old, nice big blister have
appeared and it's only a matter of time before the darned thing starts to
leak and spoils the decor. I aim to act before that stage is reached, but am
reluctant to have the roof redone in the same hideously old-fashioned way.
When you come to sell a house with a tar-and-felt flat roof, no matter how
good condition it's in, the surveyors have an absolute field day. I'm sure
they have a little word processor macro specifically to spit out a few
paragraphs of doom and gloom about flat roofs! (Needs redoing imminently,
will cost lots of money, blah blah blah, rhubarb rhubarb rhubarb.)

So, I am looking for a much more elegant and long-term covering, even if it
is going to cost considerably more. At least I'd have peace of mind, if
nothing else. Conversion to a pitched roof is not really practicable for a
variety of reasons, so I'm looking at more modern methods of recovering the
existing flat roof.

One of my neighbours appears to have a sheet metal covering on his, though I
have yet to approach him to allow me to examine it at close quarters. I have
also heard of custom-made rubber covers, rather like a fitted bottom sheet
on a bed, which is made to size and then fitted on site. I suppose it would
resemble a very heavy duty garden pond liner.

Finally, there is the question of roof insulation - there isn't any! I am
wondering whether to get the wooden boarding removed from the roof as well
as the old covering, and get the contractors to lay rolls of insulation.
(This is the method the aforementioned neighbour opted for some years ago.)
With 9" joists there would be room for, say 6" (150mm) of insulation, with a
3" air gap on top to ventilate the joists and boards. Would that be enough
of a gap?

Alternatively, I could do what I did at our last house, and that is insulate
on top of the boarding before the new covering goes on. It was something
like 50mm Kingspan if you know the stuff, only instead of being dense foam
sandwiched in foil it was sandwiched in roofing felt. It worked very well,
but the weak point was the conventional roof covering above it, which did
blister in time. Having said that, it would probably still have had to
deteriorate a lot further before it actually leaked.

Sorry this was rather verbose - please feel free to clip most if it out in
replies.

Ideas pleas?

--
Rick

"Richard Sterry" wrote in message
...
I'm sure this must be a regular chestnut on this forum, in which case
perhaps there are some useful sites and FAQs which people would be kind
enough to point me at.

I have a very large lounge, with a flat roof. It looks rather like it's an
extension to the main house, but is in fact part of the standard design
and
the joists are properly linked in with the main roof. It's in effect a
bungalow with bedrooms within the roof space, with windows on the gable
ends, and from the 'spare' roof space on one side of the first floor I can
peep through and see above the lounge ceiling. Because the joists are the
same thickness as those in the main house, they are perhaps a little
deeper
than you might expect in the circumstances - 9" in fact. The relevance of
this will become apparent later.

The main problem is that the roof is done in the traditional
'tar-and-felt'
method, and of course now that it's a few years old, nice big blister have
appeared and it's only a matter of time before the darned thing starts to
leak and spoils the decor. I aim to act before that stage is reached, but
am
reluctant to have the roof redone in the same hideously old-fashioned way.
When you come to sell a house with a tar-and-felt flat roof, no matter how
good condition it's in, the surveyors have an absolute field day. I'm sure
they have a little word processor macro specifically to spit out a few
paragraphs of doom and gloom about flat roofs! (Needs redoing imminently,
will cost lots of money, blah blah blah, rhubarb rhubarb rhubarb.)

So, I am looking for a much more elegant and long-term covering, even if
it
is going to cost considerably more. At least I'd have peace of mind, if
nothing else. Conversion to a pitched roof is not really practicable for a
variety of reasons, so I'm looking at more modern methods of recovering
the
existing flat roof.

One of my neighbours appears to have a sheet metal covering on his, though
I
have yet to approach him to allow me to examine it at close quarters. I
have
also heard of custom-made rubber covers, rather like a fitted bottom sheet
on a bed, which is made to size and then fitted on site. I suppose it
would
resemble a very heavy duty garden pond liner.

Finally, there is the question of roof insulation - there isn't any! I am
wondering whether to get the wooden boarding removed from the roof as
well
as the old covering, and get the contractors to lay rolls of insulation.
(This is the method the aforementioned neighbour opted for some years
ago.)
With 9" joists there would be room for, say 6" (150mm) of insulation, with
a
3" air gap on top to ventilate the joists and boards. Would that be enough
of a gap?

Alternatively, I could do what I did at our last house, and that is
insulate
on top of the boarding before the new covering goes on. It was something
like 50mm Kingspan if you know the stuff, only instead of being dense foam
sandwiched in foil it was sandwiched in roofing felt. It worked very well,
but the weak point was the conventional roof covering above it, which did
blister in time. Having said that, it would probably still have had to
deteriorate a lot further before it actually leaked.

Sorry this was rather verbose - please feel free to clip most if it out in
replies.

Ideas pleas?

--
Rick


============================
Consider a fibre glass roof. It's laid 'in situ' and appears to have a good
life expectancy. Do a 'google' search for 'fibre glass roof' to see what's
available.

I haven't used it myself but got the literature with a view to having a
porch roof done.

Cic.

Old roofing felts used a carrier of either paper or rag, or it could
be asbestos.
The cheapest sort in the Sheds is known as 1B type which has weak
paper carrier.
2nd problem is that the coating is oxidised bitumen, which through UV
degradation becomes brittle and cracks.
This then allows water into carrier which if paper, is bad news.
Use a high performance felt, normally based on polyester these days.
Secondly look for one coating with a "modified" bitumen, typically SBS
or APP.
These have good elongation properties and so wont crack.
This combined with a strong polyester base carrier will give you up
to 25 years life. Normally you have at least 2 layers, with top layer
having
granular coating to protect from sun/uv damage.
You can get product that is torched on ie with adhesive bitumen
provided
on the roll.
Or use a cold adhesive, or good old hot bitumen, but as with Torch On
be careful. Yes there are also butyl and other types laid cold; you
can also get customised blankets of the stuff; this means you do not
have all the joins to make yourself when laying product from a roll;
thats where water can get in.
There are alos some self adhesive types.
See http://www.ruberoid.co.uk/

"Richard Sterry" wrote in message ...
I'm sure this must be a regular chestnut on this forum, in which case
perhaps there are some useful sites and FAQs which people would be kind
enough to point me at.

I have a very large lounge, with a flat roof. It looks rather like it's an
extension to the main house, but is in fact part of the standard design and
the joists are properly linked in with the main roof. It's in effect a
bungalow with bedrooms within the roof space, with windows on the gable
ends, and from the 'spare' roof space on one side of the first floor I can
peep through and see above the lounge ceiling. Because the joists are the
same thickness as those in the main house, they are perhaps a little deeper
than you might expect in the circumstances - 9" in fact. The relevance of
this will become apparent later.

The main problem is that the roof is done in the traditional 'tar-and-felt'
method, and of course now that it's a few years old, nice big blister have
appeared and it's only a matter of time before the darned thing starts to
leak and spoils the decor. I aim to act before that stage is reached, but am
reluctant to have the roof redone in the same hideously old-fashioned way.
When you come to sell a house with a tar-and-felt flat roof, no matter how
good condition it's in, the surveyors have an absolute field day. I'm sure
they have a little word processor macro specifically to spit out a few
paragraphs of doom and gloom about flat roofs! (Needs redoing imminently,
will cost lots of money, blah blah blah, rhubarb rhubarb rhubarb.)

So, I am looking for a much more elegant and long-term covering, even if it
is going to cost considerably more. At least I'd have peace of mind, if
nothing else. Conversion to a pitched roof is not really practicable for a
variety of reasons, so I'm looking at more modern methods of recovering the
existing flat roof.

One of my neighbours appears to have a sheet metal covering on his, though I
have yet to approach him to allow me to examine it at close quarters. I have
also heard of custom-made rubber covers, rather like a fitted bottom sheet
on a bed, which is made to size and then fitted on site. I suppose it would
resemble a very heavy duty garden pond liner.

Finally, there is the question of roof insulation - there isn't any! I am
wondering whether to get the wooden boarding removed from the roof as well
as the old covering, and get the contractors to lay rolls of insulation.
(This is the method the aforementioned neighbour opted for some years ago.)
With 9" joists there would be room for, say 6" (150mm) of insulation, with a
3" air gap on top to ventilate the joists and boards. Would that be enough
of a gap?

Alternatively, I could do what I did at our last house, and that is insulate
on top of the boarding before the new covering goes on. It was something
like 50mm Kingspan if you know the stuff, only instead of being dense foam
sandwiched in foil it was sandwiched in roofing felt. It worked very well,
but the weak point was the conventional roof covering above it, which did
blister in time. Having said that, it would probably still have had to
deteriorate a lot further before it actually leaked.

Sorry this was rather verbose - please feel free to clip most if it out in
replies.

Ideas pleas?

I would suggest fibreglass laid over insulating board.
[You could also insulate between the joists, but make sure you have adequate
ventilation space]
AFAIK you can get profiled foam(?) sections which will give the required
minimum slope for drainage.

It is a while since we had our balcony over the sun lounge done this way,
but it has lasted well.

You might even consider converting this flat roof into a balcony - it sounds
as though the joists are strong enough.

You would of course need a safety barrier to Building Regs. around the edge
:-)

HTH

Dave R

On Sun, 21 Mar 2004 15:18:11 -0000, "Richard Sterry"
wrote:

I'm sure this must be a regular chestnut on this forum, in which case
perhaps there are some useful sites and FAQs which people would be kind
enough to point me at.

I have a very large lounge, with a flat roof. It looks rather like it's an
extension to the main house, but is in fact part of the standard design and
the joists are properly linked in with the main roof. It's in effect a
bungalow with bedrooms within the roof space, with windows on the gable
ends, and from the 'spare' roof space on one side of the first floor I can
peep through and see above the lounge ceiling. Because the joists are the
same thickness as those in the main house, they are perhaps a little deeper
than you might expect in the circumstances - 9" in fact. The relevance of
this will become apparent later.

The main problem is that the roof is done in the traditional 'tar-and-felt'
method, and of course now that it's a few years old, nice big blister have
appeared and it's only a matter of time before the darned thing starts to
leak and spoils the decor. I aim to act before that stage is reached, but am
reluctant to have the roof redone in the same hideously old-fashioned way.
When you come to sell a house with a tar-and-felt flat roof, no matter how
good condition it's in, the surveyors have an absolute field day. I'm sure
they have a little word processor macro specifically to spit out a few
paragraphs of doom and gloom about flat roofs! (Needs redoing imminently,
will cost lots of money, blah blah blah, rhubarb rhubarb rhubarb.)

So, I am looking for a much more elegant and long-term covering, even if it
is going to cost considerably more. At least I'd have peace of mind, if
nothing else. Conversion to a pitched roof is not really practicable for a
variety of reasons, so I'm looking at more modern methods of recovering the
existing flat roof.

One of my neighbours appears to have a sheet metal covering on his, though I
have yet to approach him to allow me to examine it at close quarters. I have
also heard of custom-made rubber covers, rather like a fitted bottom sheet
on a bed, which is made to size and then fitted on site. I suppose it would
resemble a very heavy duty garden pond liner.

Finally, there is the question of roof insulation - there isn't any! I am
wondering whether to get the wooden boarding removed from the roof as well
as the old covering, and get the contractors to lay rolls of insulation.
(This is the method the aforementioned neighbour opted for some years ago.)
With 9" joists there would be room for, say 6" (150mm) of insulation, with a
3" air gap on top to ventilate the joists and boards. Would that be enough
of a gap?

Alternatively, I could do what I did at our last house, and that is insulate
on top of the boarding before the new covering goes on. It was something
like 50mm Kingspan if you know the stuff, only instead of being dense foam
sandwiched in foil it was sandwiched in roofing felt. It worked very well,
but the weak point was the conventional roof covering above it, which did
blister in time. Having said that, it would probably still have had to
deteriorate a lot further before it actually leaked.

Sorry this was rather verbose - please feel free to clip most if it out in
replies.

Ideas pleas?
Polyroof is one of the brands of fibreglass roof covering which comes
with a decent guarantee. It is not cheap but we used it for a roof
which covers the garage and parts of the house.
I suggest you include them in your survey of suppliers.
With regard to insulation, you will need to ensuire that you
provide adequate ventilation below the roof. With good access,
polystyrene slabs can be inserted quite easily as an alternative to
glass fibre.
When we inserted insulation in similar locations I was
surprised by the extent of the improvement in comfort levels - I had
expected some improvement but not as much.

"Richard Sterry" wrote in message
...

So, I am looking for a much more elegant and long-term covering, even
if it is going to cost considerably more.

Sarnafil (http://www.sarnafil.co.uk/) is good.

--
Andy

"David W.E. Roberts" wrote in message ...

You might even consider converting this flat roof into a balcony - it sounds
as though the joists are strong enough.

Sounds nice.

I believe the old fashioned quality way of flat roofing was to use
zinc sheet metal, soldered together at the joins.

Fibreglassing is something that is diyable, if you dont mind working
with the strong fumes.


On the odd side there is always one, er, radical way of dealing with
this that I saw done once - someone put a wooden shed onto their
section of flat roof, giving them an extra utility room and avoiding
the cost of replacing the flat roof cover. Practical I suppose, but
it looked a bit odd. The balcony sounds much nicer.


Regards, NT

Thanks for your replies to this thread - all read with great interest. I
have also spoken to a few people 'in the known' in person or by phone.

The solution which apppeals to me most at the moment is a rubber membrane
covering, with hard foam (eg Kingspan) insulation underneath to make it
either a 'hot roof', or on top to make it an 'upside down' roof. However,
when I receive the quotes and see all the noughts on the end, I may not be
quite so enthusiastic!

I would be interested in hearing the views of anyone with experience of EPDM
rubber membrane roof coverings, such as Hertalan and Prelasti.

Thanks and bye from Rick in Wakefield

In article ,
N. Thornton wrote:
You might even consider converting this flat roof into a balcony - it
sounds as though the joists are strong enough.

Sounds nice.

I believe the old fashioned quality way of flat roofing was to use zinc
sheet metal, soldered together at the joins.

For a balcony, asphalt might be a better solution. This is what I've got
on my roof terrace which is an addition. I've got 'promenade tiles' on top
of this which are IIRC GRP reinforced concrete. It's all pretty practical
and hardwearing.

I made a zinc tray to replace the rotten one above a bay window, which has
a flat roof. It was pretty easy using my school taught metal working
skills.

--
*Life is hard; then you nap

Dave Plowman London SW 12
RIP Acorn

"Richard Sterry" wrote in message ...
Thanks for your replies to this thread - all read with great interest. I
have also spoken to a few people 'in the known' in person or by phone.

The solution which apppeals to me most at the moment is a rubber membrane
covering, with hard foam (eg Kingspan) insulation underneath to make it
either a 'hot roof', or on top to make it an 'upside down' roof. However,
when I receive the quotes and see all the noughts on the end, I may not be
quite so enthusiastic!

I would be interested in hearing the views of anyone with experience of EPDM
rubber membrane roof coverings, such as Hertalan and Prelasti.

Thanks and bye from Rick in Wakefield


Butyl rubber pool liners, those I've experienced, very long lived.
Dont know about anything else personally.

Regards, NT

(N. Thornton) wrote in
om:

"Richard Sterry" wrote in message
...
Thanks for your replies to this thread - all read with great
interest. I have also spoken to a few people 'in the known' in person
or by phone.

The solution which apppeals to me most at the moment is a rubber
membrane covering, with hard foam (eg Kingspan) insulation underneath
to make it either a 'hot roof', or on top to make it an 'upside down'
roof. However, when I receive the quotes and see all the noughts on
the end, I may not be quite so enthusiastic!

I would be interested in hearing the views of anyone with experience
of EPDM rubber membrane roof coverings, such as Hertalan and
Prelasti.

Thanks and bye from Rick in Wakefield


Butyl rubber pool liners, those I've experienced, very long lived.
Dont know about anything else personally.

Regards, NT


We've got a couple of sections of flat roof that we've had re-surfaced
using EPDM. Can't comment (yet) about the longevity (three years only),
but they are still looking as they were when they were fitted, and as far
as I recall they cost 30-40% more than the felt/tar/stones alternative.
Recommended local company fitted them and did a pretty good job, edges
and joins with downpipes etc look neat since the material is a lot more
malleable than the layers of felt.

Geoff
High Wycombe