I am building a lean-to conservatory and have a slightly unusual setup.
Due to getting a good price on one, but it being too small, I am using a
flat roof (draining to the side) between the conservatory and the house
- this also gives a useful escape route and a working platform for house
maintenance.

Due to various constraints, I have needed to keep the overall height
down, therefore rather than using firrings on top of the timbers, I have
the "flat" section of the roof between the joists. This means that the
conservatory butts up to a horizontal timber joist, with no height
difference.

My intention is to fibreglass the flat roof, particularly as I
fibreglassed the flat roof of the existing extension around fifteen
years ago and it's still fine.

I am still deciding how to waterproof the joint between the conservatory
and the joist and have considered making a fibreglass cap running a
short distance over the roof of the conservatory, over the joist and a
few inches vertically down the other side. My intention is that this
should not be a permanent part of the roof, but instead should be
removeable, so as to allow the glazing bar caps and roof sheets to be
removed if required.

The obvious way to make this is to put something on the roof that will
allow the fibreglass to be released, make the cap in situ and then
remove it to place a self-adhesive sealing strip or similar under it.
the question is, what to use as the release medium?

Tinfoil would work, but is eaily torn during working and will not adhere
to the roof to keep it in place while I work; clingfilm will self-adhere
but may shrink and tear under the heat of the fibreglass curing.

Any comments, experiences or suggestions appreciated.

SteveW

On Apr 17, 10:58*pm, Steve Walker
wrote:
I am building a lean-to conservatory and have a slightly unusual setup.
Due to getting a good price on one, but it being too small, I am using a
flat roof (draining to the side) between the conservatory and the house
- this also gives a useful escape route and a working platform for house
maintenance.

Due to various constraints, I have needed to keep the overall height
down, therefore rather than using firrings on top of the timbers, I have
the "flat" section of the roof between the joists. This means that the
conservatory butts up to a horizontal timber joist, with no height
difference.

My intention is to fibreglass the flat roof, particularly as I
fibreglassed the flat roof of the existing extension around fifteen
years ago and it's still fine.

I am still deciding how to waterproof the joint between the conservatory
and the joist and have considered making a fibreglass cap running a
short distance over the roof of the conservatory, over the joist and a
few inches vertically down the other side. My intention is that this
should not be a permanent part of the roof, but instead should be
removeable, so as to allow the glazing bar caps and roof sheets to be
removed if required.

The obvious way to make this is to put something on the roof that will
allow the fibreglass to be released, make the cap in situ and then
remove it to place a self-adhesive sealing strip or similar under it.
the question is, what to use as the release medium?

Tinfoil would work, but is eaily torn during working and will not adhere
to the roof to keep it in place while I work; clingfilm will self-adhere
but may shrink and tear under the heat of the fibreglass curing.

Any comments, experiences or suggestions appreciated.

SteveW

Polythene's a good multipurpose release agent. It comes off clearly,
dry, and creates a smooth surface. I don't think it matters what
happens to it once the resin's curing.


NT

On 18/04/2011 19:30, Phil L wrote:
Steve Walker wrote:
I am building a lean-to conservatory and have a slightly unusual
setup. Due to getting a good price on one, but it being too small, I
am using a flat roof (draining to the side) between the conservatory
and the house - this also gives a useful escape route and a working
platform for house maintenance.


I understand this bit

Due to various constraints, I have needed to keep the overall height
down, therefore rather than using firrings on top of the timbers, I
have the "flat" section of the roof between the joists. This means
that the conservatory butts up to a horizontal timber joist, with no
height difference.


Can't make head not tail of any of this, which makes the remainder of the
post also nonsensical

My intention is to fibreglass the flat roof, particularly as I
fibreglassed the flat roof of the existing extension around fifteen
years ago and it's still fine.

I am still deciding how to waterproof the joint between the
conservatory and the joist and have considered making a fibreglass
cap running a short distance over the roof of the conservatory, over
the joist and a few inches vertically down the other side. My
intention is that this should not be a permanent part of the roof,
but instead should be removeable, so as to allow the glazing bar caps
and roof sheets to be removed if required.

The obvious way to make this is to put something on the roof that will
allow the fibreglass to be released, make the cap in situ and then
remove it to place a self-adhesive sealing strip or similar under it.
the question is, what to use as the release medium?

Tinfoil would work, but is eaily torn during working and will not
adhere to the roof to keep it in place while I work; clingfilm will
self-adhere but may shrink and tear under the heat of the fibreglass
curing.
Any comments, experiences or suggestions appreciated.

SteveW

Any chance of a sketch? - why is there a joist affixed to the outside of
your house?

It's one of those things that makes perfect sense when you know what
it's about, hence making it difficult to judge whether it makes sense to
anyone else!

I should have said wallplate rather than joist for the one affixed to
the house.

I'll try a quick bit of ASCII art, but you'll need to view it monospaced.

This is a view from the end of the conservatory.

CCCCCCCCCJJ W
CCCCCCCCC JJFFFFFFFFFFFFFFFFFW
CCCCCCCC JJ W


C = the sloped roof of the lean-to conservatory.
J = the end of the wooden joist.
F = the surface of the flat roof (this slants from almost the top of the
joist and wallplate (back of your screen) down towards the middle height
of them as it comes out of the screen towards you.
W = the wallplate attached to the back of the house.

Below the joist, wallplate and end of the flat roof is a brick wall,
sticking out 780mm perpendicular to the house wall.

The top of the joist, down its right side, across the flat section and
up the wallplate and onto the house wall are to be fibreglassed.

My intention is then to produce a cap 5.2m long, overlapping the top
edge of the conservatory roof six inches or so, over the joist and a few
inches down the right side of the joist.

I hope that makes it clearer.

SteveW

On 18/04/2011 20:55, Phil L wrote:
Steve Walker wrote:
On 18/04/2011 19:30, Phil L wrote:
Steve Walker wrote:
I am building a lean-to conservatory and have a slightly unusual
setup. Due to getting a good price on one, but it being too small, I
am using a flat roof (draining to the side) between the conservatory
and the house - this also gives a useful escape route and a working
platform for house maintenance.


I understand this bit

Due to various constraints, I have needed to keep the overall height
down, therefore rather than using firrings on top of the timbers, I
have the "flat" section of the roof between the joists. This means
that the conservatory butts up to a horizontal timber joist, with no
height difference.


Can't make head not tail of any of this, which makes the remainder
of the post also nonsensical

My intention is to fibreglass the flat roof, particularly as I
fibreglassed the flat roof of the existing extension around fifteen
years ago and it's still fine.

I am still deciding how to waterproof the joint between the
conservatory and the joist and have considered making a fibreglass
cap running a short distance over the roof of the conservatory, over
the joist and a few inches vertically down the other side. My
intention is that this should not be a permanent part of the roof,
but instead should be removeable, so as to allow the glazing bar
caps and roof sheets to be removed if required.

The obvious way to make this is to put something on the roof that
will allow the fibreglass to be released, make the cap in situ and
then remove it to place a self-adhesive sealing strip or similar
under it. the question is, what to use as the release medium?

Tinfoil would work, but is eaily torn during working and will not
adhere to the roof to keep it in place while I work; clingfilm will
self-adhere but may shrink and tear under the heat of the fibreglass
curing.
Any comments, experiences or suggestions appreciated.

SteveW

Any chance of a sketch? - why is there a joist affixed to the
outside of your house?

It's one of those things that makes perfect sense when you know what
it's about, hence making it difficult to judge whether it makes sense
to anyone else!

I should have said wallplate rather than joist for the one affixed to
the house.

I'll try a quick bit of ASCII art, but you'll need to view it
monospaced.
This is a view from the end of the conservatory.

CCCCCCCCCJJ W
CCCCCCCCC JJFFFFFFFFFFFFFFFFFW
CCCCCCCC JJ W


C = the sloped roof of the lean-to conservatory.
J = the end of the wooden joist.
F = the surface of the flat roof (this slants from almost the top of
the joist and wallplate (back of your screen) down towards the middle
height of them as it comes out of the screen towards you.
W = the wallplate attached to the back of the house.

Below the joist, wallplate and end of the flat roof is a brick wall,
sticking out 780mm perpendicular to the house wall.

The top of the joist, down its right side, across the flat section and
up the wallplate and onto the house wall are to be fibreglassed.

My intention is then to produce a cap 5.2m long, overlapping the top
edge of the conservatory roof six inches or so, over the joist and a
few inches down the right side of the joist.

I hope that makes it clearer.

Not really becaue I've no idea how ascii works or how i'm supposed to view
it

You should just be able to see it without doing anything, it's just
plain text, but if your newsreader is set to a proportional font, spaces
and different characters will have different widths and so things won't
line up, using a monospaced font corrects this as everything has the
same width.

but it sounds like you are asking for a 5metre length of 'L' shaped
coverboard, about a tenner from your local pvc stockist, comes in 150mm,
175, 200, 225 etc etc, if it's not 'L' shaped, try them anyway as they have
all manner of profiles and sizes of pvc

No, that's no good. I need and 6" section, another 6" section at 10
degrees to that and then a two inch section at 90 degrees to that. In
addtion to that the 5.2m length has a 2-1/2" wide (1" at the top),
2-1/2" high trapezium profiled glazing bar ever 900 or so mm.

I do not want to use self-adhesive flashing - it doesn't last long -
hence thinking of a rigid, fibreglass cap, made in-situ. However,
replacement of a damaged roof sheet requires lifing the capping of the
glazing bars upward, hence I can't just continue the fibreglass of the
flat roof over them.

SteveW

On 18/04/2011 20:15, Tabby wrote:
On Apr 17, 10:58 pm, Steve Walker
wrote:
I am building a lean-to conservatory and have a slightly unusual setup.
Due to getting a good price on one, but it being too small, I am using a
flat roof (draining to the side) between the conservatory and the house
- this also gives a useful escape route and a working platform for house
maintenance.

Due to various constraints, I have needed to keep the overall height
down, therefore rather than using firrings on top of the timbers, I have
the "flat" section of the roof between the joists. This means that the
conservatory butts up to a horizontal timber joist, with no height
difference.

My intention is to fibreglass the flat roof, particularly as I
fibreglassed the flat roof of the existing extension around fifteen
years ago and it's still fine.

I am still deciding how to waterproof the joint between the conservatory
and the joist and have considered making a fibreglass cap running a
short distance over the roof of the conservatory, over the joist and a
few inches vertically down the other side. My intention is that this
should not be a permanent part of the roof, but instead should be
removeable, so as to allow the glazing bar caps and roof sheets to be
removed if required.

The obvious way to make this is to put something on the roof that will
allow the fibreglass to be released, make the cap in situ and then
remove it to place a self-adhesive sealing strip or similar under it.
the question is, what to use as the release medium?

Tinfoil would work, but is eaily torn during working and will not adhere
to the roof to keep it in place while I work; clingfilm will self-adhere
but may shrink and tear under the heat of the fibreglass curing.

Any comments, experiences or suggestions appreciated.

SteveW

Polythene's a good multipurpose release agent. It comes off clearly,
dry, and creates a smooth surface. I don't think it matters what
happens to it once the resin's curing.


NT

I'll give a piece a try. Thanks.

SteveW