I am renovating a shop. Its probably never been heated but isn't
damp. The front shop is victorian and lined with the original wood
panelling, which we'll keep. The back section of the shop about 7m x
5m I was intending to dry line.

my questions

is there any point insulating only a part section of outside wall
(probably about 40%) ie the part in the back section of the shop - it
has a window in it, and the external wall is in a vennel so its not at
all exposed

the walls are about 12" thick stone with a lime plaster on the inside
- does this need to be removed before i dryline? was intending to
build a timber frame attached to floor and ceiling about 2" away from
the wall on which to attach plasterboard.

since these walls are probably breathable (lime/stone etc) am i likely
to introduce problems by using a vapour barrier?

(also a suspended timber floor so i imagine there may be an airflow
here)

thanks

On 4 Feb, 20:15, wrote:

I am renovating a shop. Its probably never been heated but isn't
damp. The front shop is victorian and lined with the original wood
panelling, which we'll keep. The back section of the shop about 7m x
5m I was intending to dry line.

my questions

is there any point insulating only a part section of outside wall
(probably about 40%)

Yes, that will cut wall losses by nearly 40%. The more you can
insulate the better of course. Stone walls are quite bad performers
thermally.

ie the part in the back section of the shop - it
has a window in it, and the external wall is in a vennel so its not at
all exposed

the walls are about 12" thick stone with a lime plaster on the inside
- does this need to be removed before i dryline?

no

was intending to
build a timber frame attached to floor and ceiling about 2" away from
the wall on which to attach plasterboard.

since these walls are probably breathable (lime/stone etc) am i likely
to introduce problems by using a vapour barrier?

well, it is a risk, but in most cases its ok. If you dont use a vapour
barreir you'll get condensation in the insulation, so a VB is the
thing to do. Its only a minority of buildings that go on to have damp
probs.


(also a suspended timber floor so i imagine there may be an airflow
here)

thats another place you could insulate then, under the wood floor. If
you wanted to.

Making sure theres good ventilation down there will at least maximise
what wall evaporation surface is available below the floor.


NT

wrote:
I am renovating a shop. Its probably never been heated but isn't
damp. The front shop is victorian and lined with the original wood
panelling, which we'll keep. The back section of the shop about 7m x
5m I was intending to dry line.

my questions

is there any point insulating only a part section of outside wall
(probably about 40%) ie the part in the back section of the shop - it
has a window in it, and the external wall is in a vennel so its not at
all exposed


yes. Every little helps

the walls are about 12" thick stone with a lime plaster on the inside
- does this need to be removed before i dryline?

No.

was intending to
build a timber frame attached to floor and ceiling about 2" away from
the wall on which to attach plasterboard.

Good.

since these walls are probably breathable (lime/stone etc) am i likely
to introduce problems by using a vapour barrier?

No. Quite the reverse I would say. You will be reducing moisture flow to
the inside of he wall..what moisture gets in will be via rain on the
outer wall and any rising damp.

As long as that can get OUIT to teh outside, all will be well

If it bothers you shove a plastic sheet behind the studwork so that even
if the wall DOS get damp, it wont rot the wood.

Then use foil backed plasterboard. as well.




(also a suspended timber floor so i imagine there may be an airflow
here)

Lift it, insulate and seal it, and refit.


thanks

On 5 Feb, 01:48, The Natural Philosopher wrote:
wrote:
I am renovating a shop. Its probably never been heated but isn't
damp. The front shop is victorian and lined with the original wood
panelling, which we'll keep. The back section of the shop about 7m x
5m I was intending to dry line.

my questions

is there any point insulating only a part section of outside wall
(probably about 40%) ie the part in the back section of the shop - it
has a window in it, and the external wall is in a vennel so its not at
all exposed

yes. Every little helps

the walls are about 12" thick stone with a lime plaster on the inside
- does this need to be removed before i dryline?

No.

was intending to

build a timber frame attached to floor and ceiling about 2" away from
the wall on which to attach plasterboard.

Good.

since these walls are probably breathable (lime/stone etc) am i likely
to introduce problems by using a vapour barrier?

No. Quite the reverse I would say. You will be reducing moisture flow to
the inside of he wall..what moisture gets in will be via rain on the
outer wall and any rising damp.

As long as that can get OUIT to teh outside, all will be well

If it bothers you shove a plastic sheet behind the studwork so that even
if the wall DOS get damp, it wont rot the wood.

Then use foil backed plasterboard. as well.

(also a suspended timber floor so i imagine there may be an airflow
here)

Lift it, insulate and seal it, and refit.



thanks

.... good advice thanks.

It would be a major undertaking to insulate the floor (I doubt whether
the floorboards would lift undamaged) but if i did I would have about
6" to play with - do I need an airgap or could insulation be packed
into the full depth - and which would be better rockwool or rigid
boards celotex/kingspan.
there is no dpc as such but there is a layer of tar over the solum
which i'm assuming has the same effect - could i use loose fill?
Warmcell (which would only allow 150mm rather than the recommended
250mm) - but would mean i could only lift sections of the floor and
pack it in.

i was intending to sand the floor boards as the final finish so
minimum disturbance would be best and i don't have a limitless budget!

or if i do go to all this trouble insulating the floor then maybe
underfloor heating would be the way to go? ...to many options??

In article . com,
writes

It would be a major undertaking to insulate the floor (I doubt whether
the floorboards would lift undamaged) but if i did I would have about
6" to play with - do I need an airgap or could insulation be packed
into the full depth - and which would be better rockwool or rigid
boards celotex/kingspan.
there is no dpc as such but there is a layer of tar over the solum
which i'm assuming has the same effect - could i use loose fill?
Warmcell (which would only allow 150mm rather than the recommended
250mm) - but would mean i could only lift sections of the floor and
pack it in.

i was intending to sand the floor boards as the final finish so
minimum disturbance would be best and i don't have a limitless budget!

or if i do go to all this trouble insulating the floor then maybe
underfloor heating would be the way to go? ...to many options??

Underfloor insulation is generally a lot of work for little return, heat loss
through floors is estimated to be one quarter of that lost through ceilings
so it is generally an issue of comfort level.

I have insulated my own floors (with 150mm of fibreglass over a hardboard
sub-floor) and I welcome the benefit but this was a situation where there
was a deep and well ventilated underfloor with baltic winds howling through
so I felt obliged to put in some sort of barrier.

You have a limited space underfloor which is less likely to have a howler
blowing through. In your place I'd be inclined to fully draught proof the floor
(sorry not an easy option with bare sanded boards) apply taped and sealed
hardboard followed by substantial underlay and carpet (or dense insulation
and lino if commercial) and leave it at that.

On no account poor in loose fill or do anything to compromise air
circulation or you'll be looking at rot in the long term.
--
fred
Plusnet - I hope you like vanilla

fred wrote:
In article . com,
writes
It would be a major undertaking to insulate the floor (I doubt whether
the floorboards would lift undamaged) but if i did I would have about
6" to play with - do I need an airgap or could insulation be packed
into the full depth - and which would be better rockwool or rigid
boards celotex/kingspan.
there is no dpc as such but there is a layer of tar over the solum
which i'm assuming has the same effect - could i use loose fill?
Warmcell (which would only allow 150mm rather than the recommended
250mm) - but would mean i could only lift sections of the floor and
pack it in.

i was intending to sand the floor boards as the final finish so
minimum disturbance would be best and i don't have a limitless budget!

or if i do go to all this trouble insulating the floor then maybe
underfloor heating would be the way to go? ...to many options??

Underfloor insulation is generally a lot of work for little return, heat loss
through floors is estimated to be one quarter of that lost through ceilings
so it is generally an issue of comfort level.


Umm. Not really. Once your walls are done and your ceiling is done, it
becomes the dominant path....a typical slab has a U value over 1.5..

I have insulated my own floors (with 150mm of fibreglass over a hardboard
sub-floor) and I welcome the benefit but this was a situation where there
was a deep and well ventilated underfloor with baltic winds howling through
so I felt obliged to put in some sort of barrier.

You have a limited space underfloor which is less likely to have a howler
blowing through. In your place I'd be inclined to fully draught proof the floor
(sorry not an easy option with bare sanded boards) apply taped and sealed
hardboard followed by substantial underlay and carpet (or dense insulation
and lino if commercial) and leave it at that.

On no account poor in loose fill or do anything to compromise air
circulation or you'll be looking at rot in the long term.


True enough.

In the end its the OP's call. there is no doubt in my mind that once
you do a pukkah job on the walls, the floor remains a very real source
of heatloss.

Whether you then go insulation and UFH and a thin surface, or a bloody
great shag carpet and radiators, is personal choice.

For bare boards i would always use UFH.

In article , The Natural
Philosopher writes
fred wrote:

Underfloor insulation is generally a lot of work for little return, heat loss
through floors is estimated to be one quarter of that lost through ceilings
so it is generally an issue of comfort level.


Umm. Not really. Once your walls are done and your ceiling is done, it
becomes the dominant path....a typical slab has a U value over 1.5..

Of course, when you start plugging the leaks in an old bucket the last hole
will always be responsible for 100% of the loss ;-)

Btw, this is boards, not a slab.

I have insulated my own floors (with 150mm of fibreglass over a hardboard
sub-floor) and I welcome the benefit but this was a situation where there
was a deep and well ventilated underfloor with baltic winds howling through
so I felt obliged to put in some sort of barrier.

You have a limited space underfloor which is less likely to have a howler
blowing through. In your place I'd be inclined to fully draught proof the floor
(sorry not an easy option with bare sanded boards) apply taped and sealed
hardboard followed by substantial underlay and carpet (or dense insulation
and lino if commercial) and leave it at that.

On no account poor in loose fill or do anything to compromise air
circulation or you'll be looking at rot in the long term.

True enough.

In the end its the OP's call. there is no doubt in my mind that once
you do a pukkah job on the walls, the floor remains a very real source
of heatloss.

Whether you then go insulation and UFH and a thin surface, or a bloody
great shag carpet and radiators, is personal choice.

For bare boards i would always use UFH.

Go that route and you'll definitely need top notch floor insulation but that
means lifting the floor which was the step I had hoped to save the o/p. A
recent post (which I haven't checked for accuracy) suggested that a
minimal (12mm?) thickness of celotex on a solid (or was it cavity) double
brick wall was enough cut the heat loss in half. Given that I'd be inclined to
forgo lifting the floor and add a thin but dense insulator with a ply sub-floor
(if anything).
--
fred
Plusnet - I hope you like vanilla

On 5 Feb, 22:47, fred wrote:
In article , The Natural
Philosopher writesfred wrote:

Underfloor insulation is generally a lot of work for little return, heat loss
through floors is estimated to be one quarter of that lost through ceilings
so it is generally an issue of comfort level.

Umm. Not really. Once your walls are done and your ceiling is done, it
becomes the dominant path....a typical slab has a U value over 1.5..

Of course, when you start plugging the leaks in an old bucket the last hole
will always be responsible for 100% of the loss ;-)

Btw, this is boards, not a slab.



I have insulated my own floors (with 150mm of fibreglass over a hardboard
sub-floor) and I welcome the benefit but this was a situation where there
was a deep and well ventilated underfloor with baltic winds howling through
so I felt obliged to put in some sort of barrier.

You have a limited space underfloor which is less likely to have a howler
blowing through. In your place I'd be inclined to fully draught proof the floor
(sorry not an easy option with bare sanded boards) apply taped and sealed
hardboard followed by substantial underlay and carpet (or dense insulation
and lino if commercial) and leave it at that.

On no account poor in loose fill or do anything to compromise air
circulation or you'll be looking at rot in the long term.

True enough.

In the end its the OP's call. there is no doubt in my mind that once
you do a pukkah job on the walls, the floor remains a very real source
of heatloss.

Whether you then go insulation and UFH and a thin surface, or a bloody
great shag carpet and radiators, is personal choice.

For bare boards i would always use UFH.

Go that route and you'll definitely need top notch floor insulation but that
means lifting the floor which was the step I had hoped to save the o/p. A
recent post (which I haven't checked for accuracy) suggested that a
minimal (12mm?) thickness of celotex on a solid (or was it cavity) double
brick wall was enough cut the heat loss in half. Given that I'd be inclined to
forgo lifting the floor and add a thin but dense insulator with a ply sub-floor
(if anything).
--
fred
Plusnet - I hope you like vanilla

ok i've done a little bit more investigating and i've almost convinced
myself it would be a good idea to lift the floor, lay 18mm ply
subfloor and then T&G bamboo planks. this way i can get a better
finish, be confident about draught proofing and i can probably use the
old boards upstairs... so under the floor i have 6" joists resting on
bricks on a tar solum (i presume the tar was an old method of DPC) no
sign of any damp/rot in the areas already lifted.

.... i'm wondering is this enough space (only about 7") to fit any
insulation that would have a worthwhile effect (25mm/50mm? - rigid
board type) - without comprimising airflow?
the floor is 70m2 and is vented at the front only.

(ps a shag pile carpet is not in the equation - this will be a coffee
shop and gallery - and i want it to be warm because we're trying to
promote biomass heating by installing a wood pellet stove boiler...)