i've been doing a lot of googling and searching on this group re
insulating floors - but need some clarification on my own particular
setup. i have the opportunity to insulate a ground floor because i'm
lifting the floorboards and laying a ply subfloor followed by bamboo
T&G planks. the floor joists 6" x 2" are resting on bricks on a
solum to which a thick layer of tar has been applied (DPC I
presume?). So in all there is only 7" - 8" airpace. The floor is is
over two rooms. all in the floor area is approx 70m2 (7.5x5 &
6.5x5). The front is ventilated with two grills, but I cant see any
other ventilation, and because the ground slopes up the joists towards
the back are under ground level. There is no sign of any dampness at
present.

.... is it practicle/beneficial to insulate this space, what thickness
can i use without comprimising the airflow?

wrote:
i've been doing a lot of googling and searching on this group re
insulating floors - but need some clarification on my own particular
setup. i have the opportunity to insulate a ground floor because i'm
lifting the floorboards and laying a ply subfloor followed by bamboo
T&G planks. the floor joists 6" x 2" are resting on bricks on a
solum to which a thick layer of tar has been applied (DPC I
presume?). So in all there is only 7" - 8" airpace. The floor is is
over two rooms. all in the floor area is approx 70m2 (7.5x5 &
6.5x5). The front is ventilated with two grills, but I cant see any
other ventilation, and because the ground slopes up the joists towards
the back are under ground level. There is no sign of any dampness at
present.

... is it practicle/beneficial to insulate this space, what thickness
can i use without comprimising the airflow?

Yes it is practicable,

Use about 2-3" of celotex.

On 19 Feb, 12:09, The Natural Philosopher wrote:
wrote:
i've been doing a lot of googling and searching on this group re
insulating floors - but need some clarification on my own particular
setup. i have the opportunity to insulate a ground floor because i'm
lifting the floorboards and laying a ply subfloor followed by bamboo
T&G planks. the floor joists 6" x 2" are resting on bricks on a
solum to which a thick layer of tar has been applied (DPC I
presume?). So in all there is only 7" - 8" airpace. The floor is is
over two rooms. all in the floor area is approx 70m2 (7.5x5 &
6.5x5). The front is ventilated with two grills, but I cant see any
other ventilation, and because the ground slopes up the joists towards
the back are under ground level. There is no sign of any dampness at
present.

... is it practicle/beneficial to insulate this space, what thickness
can i use without comprimising the airflow?

Yes it is practicable,

Use about 2-3" of celotex.- Hide quoted text -

- Show quoted text -

Thanks... what about a vapour barrier? over the ply perhaps.
Polystyrene is cheaper would this be a suitable alternative to
celotex?

On Mon, 19 Feb 2007 03:09:17 -0800, mcmook wrote:

... is it practicle/beneficial to insulate this space, what thickness
can i use without comprimising the airflow?

Sounds like underfloor heating without the heating. Er, have you
considered .... ?

wrote:
On 19 Feb, 12:09, The Natural Philosopher wrote:
wrote:
i've been doing a lot of googling and searching on this group re
insulating floors - but need some clarification on my own particular
setup. i have the opportunity to insulate a ground floor because i'm
lifting the floorboards and laying a ply subfloor followed by bamboo
T&G planks. the floor joists 6" x 2" are resting on bricks on a
solum to which a thick layer of tar has been applied (DPC I
presume?). So in all there is only 7" - 8" airpace. The floor is is
over two rooms. all in the floor area is approx 70m2 (7.5x5 &
6.5x5). The front is ventilated with two grills, but I cant see any
other ventilation, and because the ground slopes up the joists towards
the back are under ground level. There is no sign of any dampness at
present.
... is it practicle/beneficial to insulate this space, what thickness
can i use without comprimising the airflow?
Yes it is practicable,

Use about 2-3" of celotex.- Hide quoted text -

- Show quoted text -

Thanks... what about a vapour barrier? over the ply perhaps.
Polystyrene is cheaper would this be a suitable alternative to
celotex?


Celotex is foil coated and installed with foil sealing tape.

Polystyrene is only half as good - need twice as much - and might be a
fire/toxic fume risk. I really only like to use it inside a screed. It
really is *very* nasty in a fire. And it burns very well.

Celotex simply chars..it won't sustain combustion. I tried..

In article , The Natural
Philosopher writes
wrote:

Thanks... what about a vapour barrier? over the ply perhaps.
Polystyrene is cheaper would this be a suitable alternative to
celotex?


Celotex is foil coated and installed with foil sealing tape.

Polystyrene is only half as good - need twice as much - and might be a
fire/toxic fume risk. I really only like to use it inside a screed. It
really is *very* nasty in a fire. And it burns very well.

Celotex simply chars..it won't sustain combustion. I tried..
Very good point.

Maybe rockwool batts would be the way to go for a budget solution,
100mm would be equivalent to 65mm of Celotex and still leave a healthy
airgap.
--
fred
Plusnet - I hope you like vanilla

fred wrote:
In article , The Natural
Philosopher writes
wrote:
Thanks... what about a vapour barrier? over the ply perhaps.
Polystyrene is cheaper would this be a suitable alternative to
celotex?

Celotex is foil coated and installed with foil sealing tape.

Polystyrene is only half as good - need twice as much - and might be a
fire/toxic fume risk. I really only like to use it inside a screed. It
really is *very* nasty in a fire. And it burns very well.

Celotex simply chars..it won't sustain combustion. I tried..
Very good point.

Maybe rockwool batts would be the way to go for a budget solution,
100mm would be equivalent to 65mm of Celotex and still leave a healthy
airgap.
Not good if there are underfloor draughts.