Our house is about 130 years old, we have a room in our roof space in
which the angled ceiling is plasterboard fastened to the underside of
the rafters (leaving about a 4" gap between the underside of the roof
and the plasterboard.

The plasterboard is a recent replacement for lathe and plaster.

Although the room looks great we didn't put any insulation between the
rafters and the plasterboard (worried about ventilation) meaning that
we have a very large uninsulated roof area.

Is there anything I can do to insulate this space that doesn't involve
removing the board and that wont compromise the ventilation between the
rafters.

Thanks

Richard

Jacko wrote:
Our house is about 130 years old, we have a room in our roof space in
which the angled ceiling is plasterboard fastened to the underside of
the rafters (leaving about a 4" gap between the underside of the roof
and the plasterboard.

The plasterboard is a recent replacement for lathe and plaster.

Although the room looks great we didn't put any insulation between the
rafters and the plasterboard (worried about ventilation) meaning that
we have a very large uninsulated roof area.

Is there anything I can do to insulate this space that doesn't involve
removing the board and that wont compromise the ventilation between the
rafters.

Thanks

Richard

Celotex is designed for this, but I doubt it will be easy to fit or
effective, without removing the ceiling, no.

Bite the bullet?.

The Natural Philosopher wrote:
Jacko wrote:

Our house is about 130 years old, we have a room in our roof space in
which the angled ceiling is plasterboard fastened to the underside of
the rafters (leaving about a 4" gap between the underside of the roof
and the plasterboard.

The plasterboard is a recent replacement for lathe and plaster.

Although the room looks great we didn't put any insulation between the
rafters and the plasterboard (worried about ventilation) meaning that
we have a very large uninsulated roof area.

Is there anything I can do to insulate this space that doesn't involve
removing the board and that wont compromise the ventilation between the
rafters.

Thanks

Richard

Celotex is designed for this, but I doubt it will be easy to fit or
effective, without removing the ceiling, no.

Bite the bullet?.

Why would it be ineffective to attach it to the existing ceiling?

NT

wrote:
The Natural Philosopher wrote:
Jacko wrote:

Our house is about 130 years old, we have a room in our roof space in
which the angled ceiling is plasterboard fastened to the underside of
the rafters (leaving about a 4" gap between the underside of the roof
and the plasterboard.

The plasterboard is a recent replacement for lathe and plaster.

Although the room looks great we didn't put any insulation between the
rafters and the plasterboard (worried about ventilation) meaning that
we have a very large uninsulated roof area.

Is there anything I can do to insulate this space that doesn't involve
removing the board and that wont compromise the ventilation between the
rafters.

Thanks

Richard

Celotex is designed for this, but I doubt it will be easy to fit or
effective, without removing the ceiling, no.

Bite the bullet?.

Why would it be ineffective to attach it to the existing ceiling?

NT

Oh..create a false ceiling inside? Still needs a whole new ceiling
added..might as well take the oldone down..

The Natural Philosopher wrote:
wrote:
The Natural Philosopher wrote:
Jacko wrote:

Celotex is designed for this, but I doubt it will be easy to fit or
effective, without removing the ceiling, no.

Bite the bullet?.

Why would it be ineffective to attach it to the existing ceiling?

Oh..create a false ceiling inside? Still needs a whole new ceiling
added..might as well take the oldone down..

What I meant was just apply the insulation to the existing PB or L&P,
and plaster over it.. No need to remove anything.


NT

wrote:
The Natural Philosopher wrote:
wrote:
The Natural Philosopher wrote:
Jacko wrote:

Celotex is designed for this, but I doubt it will be easy to fit or
effective, without removing the ceiling, no.

Bite the bullet?.

Why would it be ineffective to attach it to the existing ceiling?

Oh..create a false ceiling inside? Still needs a whole new ceiling
added..might as well take the oldone down..

What I meant was just apply the insulation to the existing PB or L&P,
and plaster over it.. No need to remove anything.


Well its easier to board up and then skim..but I take the point. The
issue is whether that is less hassle than taking down what is up there,
and the loss of space..if these come out on the plus side, then of
course its a good way to go. Here they wouldn't.


NT

Jacko wrote:
Our house is about 130 years old, we have a room in our roof space in
which the angled ceiling is plasterboard fastened to the underside of
the rafters (leaving about a 4" gap between the underside of the roof
and the plasterboard.

Is the roof membrane breathable, or is it just tar paper?

The plasterboard is a recent replacement for lathe and plaster.

Although the room looks great we didn't put any insulation between the
rafters and the plasterboard (worried about ventilation) meaning that
we have a very large uninsulated roof area.

Is there anything I can do to insulate this space that doesn't involve
removing the board and that wont compromise the ventilation between the
rafters.

Kingspan over the whole lot, and new plasterboard over the top of it.

I'd recommend biting the bullet.
Get 25mm kingspan.
Rip off the existing plasterboard.
Place the 25mm kingspan along the rafters.
Get some 75mm thick fibreglass, and some string or mesh.

Cut the fibreflass so that it fits between the rafters.

Fix the mesh onto the joists as you go up, holding the fiberflass up.
Now, put vapour barrier plasterboard over this.

The easier way - if you have a reasonable budget is to use either
rocksilk, or kingspan - which can simply be pressed into the rafters and
then plasterboarder over.

Jacko wrote:
Our house is about 130 years old, we have a room in our roof space in
which the angled ceiling is plasterboard fastened to the underside of
the rafters (leaving about a 4" gap between the underside of the roof
and the plasterboard.

The plasterboard is a recent replacement for lathe and plaster.

Although the room looks great we didn't put any insulation between the
rafters and the plasterboard (worried about ventilation) meaning that
we have a very large uninsulated roof area.

Is there anything I can do to insulate this space that doesn't involve
removing the board and that wont compromise the ventilation between the
rafters.

Thanks

Richard


I am battling with a similar situation where the original lath and
plaster walls/celing are intact. On one side I have good access from the
loft space so I hope to nudge 50mm celotex up between the rafters,
leaving a 2" gap under the roof tiles. The other side is not so easy so
I am resigned to taking some of the walls and ceiling down.
As the man says, best to bite the bullet and put it down to experience :-)

Thanks for the replies, I suspected this would be the case. The roof is
original.

The area to be removed would be massive and I'm concerned about losing
any ventilation so I might be tempted to take the advice of leaving the
plasterboard as is and putting 50x50 battens up, insulation in between
then more plasterboard over the top to give me a finish - any thoughts
on this?

Cheers

Richard

Jacko wrote:
Thanks for the replies, I suspected this would be the case. The roof is
original.

The area to be removed would be massive and I'm concerned about losing
any ventilation so I might be tempted to take the advice of leaving the
plasterboard as is and putting 50x50 battens up, insulation in between
then more plasterboard over the top to give me a finish - any thoughts
on this?

Cheers

Richard


Plenty of room for ventilation with 50mm celotex. I'd rather take the PB
down and not lose the space

Jacko wrote:
Thanks for the replies, I suspected this would be the case. The roof is
original.

The area to be removed would be massive and I'm concerned about losing
any ventilation so I might be tempted to take the advice of leaving the
plasterboard as is and putting 50x50 battens up, insulation in between
then more plasterboard over the top to give me a finish - any thoughts
on this?



If that is your choice, go for it. just seal the whole thing up
completely before plasterboarding over.


Cheers

Richard

Jacko wrote:
Thanks for the replies, I suspected this would be the case. The roof is
original.

The area to be removed would be massive and I'm concerned about losing
any ventilation so I might be tempted to take the advice of leaving the
plasterboard as is and putting 50x50 battens up, insulation in between
then more plasterboard over the top to give me a finish - any thoughts
on this?

It sounds like you have plenty of room and are going to get the best of
both worlds. Even if you hadn't lower down, the method would be fine
nearer the apex.