[Keith Dunbar]

Further to previous posts about calculating radiator sizes, my 17th century
timberframed house has been renovated as far as I can tell by replacing all
the old wall materials with rendered breeze blocks. The walls seem to vary
in width in different places, but the minimum seems to be 9 inches,
presumably solid breeze block. My attempts to google for a u value haven't
been very successful. Can anyone suggest a reasonable u value for this wall
construction that I can use in my calculations?

TIA

Keith

[The Natural Philosopher]

Keith Dunbar wrote:
Further to previous posts about calculating radiator sizes, my 17th century
timberframed house has been renovated as far as I can tell by replacing all
the old wall materials with rendered breeze blocks. The walls seem to vary
in width in different places, but the minimum seems to be 9 inches,
presumably solid breeze block. My attempts to google for a u value haven't
been very successful. Can anyone suggest a reasonable u value for this wall
construction that I can use in my calculations?


well I have K values (divide by width in meters for U Value)

aerated concteret 0.16
lightweigght block 0.19
med block 0.51
heavy concrete 1.63
screed 0.38
Brick 0.64

9" is about 125mm or 1/8th of a meter, which gives possible U values
depending on density, from 1.28 up to 12 or 13 or so.

I would suspect around 4-5. Similar to brick.

Ultimately it doesn't matter cos you want to line it all anyway don't you?

Or do you need to expose timbers?


TIA

Keith

[Tony Bryer]

On Fri, 14 Sep 2007 05:15:42 GMT Keith Dunbar wrote :
Further to previous posts about calculating radiator sizes, my 17th century
timberframed house has been renovated as far as I can tell by replacing all
the old wall materials with rendered breeze blocks. The walls seem to vary
in width in different places, but the minimum seems to be 9 inches,
presumably solid breeze block. My attempts to google for a u value haven't
been very successful. Can anyone suggest a reasonable u value for this
wall construction that I can use in my calculations?

If they are medium density blocks (1400kg/m3), then about 1.5. Aerated
concrete (Thermalite/Celcon, 500kg/m3) about 0.6.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk

[Keith Dunbar]

"The Natural Philosopher" wrote in message
...
Keith Dunbar wrote:
Further to previous posts about calculating radiator sizes, my 17th
century timberframed house has been renovated as far as I can tell by
replacing all the old wall materials with rendered breeze blocks. The
walls seem to vary in width in different places, but the minimum seems to
be 9 inches, presumably solid breeze block. My attempts to google for a
u value haven't been very successful. Can anyone suggest a reasonable u
value for this wall construction that I can use in my calculations?


well I have K values (divide by width in meters for U Value)

aerated concteret 0.16
lightweigght block 0.19
med block 0.51
heavy concrete 1.63
screed 0.38
Brick 0.64

9" is about 125mm or 1/8th of a meter, which gives possible U values
depending on density, from 1.28 up to 12 or 13 or so.

I would suspect around 4-5. Similar to brick.

Ultimately it doesn't matter cos you want to line it all anyway don't you?

Or do you need to expose timbers?

I hadn't planned to alter the walls in any way - I'm just trying to check on
radiator sizes. Are you sure about these values? Values I have vary from
0.65 (11" insulated brick cavity) to 2.44 (9" solid brick). Trouble is I
have no easy way to find out what type of block was used. The only clue is
that the work was done in 1967.

Keith

[Keith Dunbar]

"Tony Bryer" wrote in message
...
On Fri, 14 Sep 2007 05:15:42 GMT Keith Dunbar wrote :
Further to previous posts about calculating radiator sizes, my 17th
century
timberframed house has been renovated as far as I can tell by replacing
all
the old wall materials with rendered breeze blocks. The walls seem to
vary
in width in different places, but the minimum seems to be 9 inches,
presumably solid breeze block. My attempts to google for a u value
haven't
been very successful. Can anyone suggest a reasonable u value for this
wall construction that I can use in my calculations?

If they are medium density blocks (1400kg/m3), then about 1.5. Aerated
concrete (Thermalite/Celcon, 500kg/m3) about 0.6.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk

I guess I should just set an arbitrary in-between figure to work with -
perhaps 1.5?

Keith

[Andy Hall]

On 2007-09-14 15:30:19 +0100, "Keith Dunbar" said:


"Tony Bryer" wrote in message
...
On Fri, 14 Sep 2007 05:15:42 GMT Keith Dunbar wrote :
Further to previous posts about calculating radiator sizes, my 17th
century
timberframed house has been renovated as far as I can tell by replacing
all
the old wall materials with rendered breeze blocks. The walls seem to
vary
in width in different places, but the minimum seems to be 9 inches,
presumably solid breeze block. My attempts to google for a u value
haven't
been very successful. Can anyone suggest a reasonable u value for this
wall construction that I can use in my calculations?

If they are medium density blocks (1400kg/m3), then about 1.5. Aerated
concrete (Thermalite/Celcon, 500kg/m3) about 0.6.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk

I guess I should just set an arbitrary in-between figure to work with -
perhaps 1.5?

Keith



The other thing is that as this is for a heating sizing exercise, take
a look on the spreadsheet or program that you use at how much heat loss
is involved in watts once the areas are taken into account.

For example, you may find that a wall that you find is difficult to
determine is not a major contributor to heat loss because of a
relatively small area. There's no point in fretting about +/- 20%
on 500W on one wall if there's 2kW going out of another wall that you
can determine easily.

[Timothy Murphy]

Andy Hall wrote:

For example, you may find that a wall that you find is difficult to
determine is not a major contributor to heat loss because of a
relatively small area. There's no point in fretting about +/- 20%
on 500W on one wall if there's 2kW going out of another wall that you
can determine easily.

All these figures seem absurdly high to me.
I cannot imagine a room which would not be warmed up by a 2kW fire,
unless there is an actual opening to the outside.

[Andy Hall]

On 2007-09-14 17:16:26 +0100, Timothy Murphy said:

Andy Hall wrote:

For example, you may find that a wall that you find is difficult to
determine is not a major contributor to heat loss because of a
relatively small area. There's no point in fretting about +/- 20%
on 500W on one wall if there's 2kW going out of another wall that you
can determine easily.

All these figures seem absurdly high to me.
I cannot imagine a room which would not be warmed up by a 2kW fire,
unless there is an actual opening to the outside.

I just used the figures to illustrate the point about focussing on the
components that actually matter. They are deliberately high.

I could have equally said 20% on 50W and 500W through the other wall.

[Newshound]

"Keith Dunbar" wrote in message
...

"Tony Bryer" wrote in message
...
On Fri, 14 Sep 2007 05:15:42 GMT Keith Dunbar wrote :
Further to previous posts about calculating radiator sizes, my 17th
century
timberframed house has been renovated as far as I can tell by replacing
all
the old wall materials with rendered breeze blocks. The walls seem to
vary
in width in different places, but the minimum seems to be 9 inches,
presumably solid breeze block. My attempts to google for a u value
haven't
been very successful. Can anyone suggest a reasonable u value for this
wall construction that I can use in my calculations?

If they are medium density blocks (1400kg/m3), then about 1.5. Aerated
concrete (Thermalite/Celcon, 500kg/m3) about 0.6.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk

I guess I should just set an arbitrary in-between figure to work with -
perhaps 1.5?

Keith

Sample drilling will tell you whether it's lighweight blocks or not. Just an
old carbon steel drill: will go straight through thermalite, won't touch
concrete

[[email protected]]

On 14 Sep, 06:15, "Keith Dunbar" wrote:
Further to previous posts about calculating radiator sizes, my 17th century
timberframed house has been renovated as far as I can tell by replacing all
the old wall materials with rendered breeze blocks. The walls seem to vary
in width in different places, but the minimum seems to be 9 inches,
presumably solid breeze block. My attempts to google for a u value haven't
been very successful. Can anyone suggest a reasonable u value for this wall
construction that I can use in my calculations?

TIA

Keith

My guess is between 2 and 3
Chris
I would unhesitatingly line it intermally if possible
Let me know if you want a spec for this as I am doing this myself and
have developed quite a good system even tho i say it myself!
chris

[Keith Dunbar]

wrote in message
oups.com...
On 14 Sep, 06:15, "Keith Dunbar" wrote:
Further to previous posts about calculating radiator sizes, my 17th
century
timberframed house has been renovated as far as I can tell by replacing
all
the old wall materials with rendered breeze blocks. The walls seem to
vary
in width in different places, but the minimum seems to be 9 inches,
presumably solid breeze block. My attempts to google for a u value
haven't
been very successful. Can anyone suggest a reasonable u value for this
wall
construction that I can use in my calculations?

TIA

Keith

My guess is between 2 and 3
Chris
I would unhesitatingly line it intermally if possible
Let me know if you want a spec for this as I am doing this myself and
have developed quite a good system even tho i say it myself!
chris

There are loads of beams visible inside, so lining isn't really an option
without losing a lot of the character of the place. But thanks anyway for
the offer.

Keith

[Keith Dunbar]

"Newshound" wrote in message
...

"Keith Dunbar" wrote in message
...

"Tony Bryer" wrote in message
...
On Fri, 14 Sep 2007 05:15:42 GMT Keith Dunbar wrote :
Further to previous posts about calculating radiator sizes, my 17th
century
timberframed house has been renovated as far as I can tell by replacing
all
the old wall materials with rendered breeze blocks. The walls seem to
vary
in width in different places, but the minimum seems to be 9 inches,
presumably solid breeze block. My attempts to google for a u value
haven't
been very successful. Can anyone suggest a reasonable u value for this
wall construction that I can use in my calculations?

If they are medium density blocks (1400kg/m3), then about 1.5. Aerated
concrete (Thermalite/Celcon, 500kg/m3) about 0.6.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk

I guess I should just set an arbitrary in-between figure to work with -
perhaps 1.5?

Keith

Sample drilling will tell you whether it's lighweight blocks or not. Just
an old carbon steel drill: will go straight through thermalite, won't
touch concrete
Ah, I think I may already know the answer then. But I shall do a drill test
later. If it is concrete, what u value would we be talking about for 9".

Keith

[The Natural Philosopher]

Keith Dunbar wrote:
"The Natural Philosopher" wrote in message
...
Keith Dunbar wrote:
Further to previous posts about calculating radiator sizes, my 17th
century timberframed house has been renovated as far as I can tell by
replacing all the old wall materials with rendered breeze blocks. The
walls seem to vary in width in different places, but the minimum seems to
be 9 inches, presumably solid breeze block. My attempts to google for a
u value haven't been very successful. Can anyone suggest a reasonable u
value for this wall construction that I can use in my calculations?

well I have K values (divide by width in meters for U Value)

aerated concteret 0.16
lightweigght block 0.19
med block 0.51
heavy concrete 1.63
screed 0.38
Brick 0.64

9" is about 125mm or 1/8th of a meter, which gives possible U values
depending on density, from 1.28 up to 12 or 13 or so.

I would suspect around 4-5. Similar to brick.

Ultimately it doesn't matter cos you want to line it all anyway don't you?

Or do you need to expose timbers?
I hadn't planned to alter the walls in any way - I'm just trying to check on
radiator sizes. Are you sure about these values? Values I have vary from
0.65 (11" insulated brick cavity) to 2.44 (9" solid brick). Trouble is I
have no easy way to find out what type of block was used. The only clue is
that the work was done in 1967.

\
If you are simply sizing radiators, you will want to oversize anyway for
fast warm up times.

Assume 9" solid brick.


Keith

[The Natural Philosopher]

Timothy Murphy wrote:
Andy Hall wrote:

For example, you may find that a wall that you find is difficult to
determine is not a major contributor to heat loss because of a
relatively small area. There's no point in fretting about +/- 20%
on 500W on one wall if there's 2kW going out of another wall that you
can determine easily.

All these figures seem absurdly high to me.
I cannot imagine a room which would not be warmed up by a 2kW fire,
unless there is an actual opening to the outside.


I can.

I used to live i an uninuslated 9" solid brick cottage with leaky sahs
windows.

Around 2Kw ona small room.

Now I get away with around 500W/room or less.

[The Natural Philosopher]

Keith Dunbar wrote:
wrote in message
oups.com...
On 14 Sep, 06:15, "Keith Dunbar" wrote:
Further to previous posts about calculating radiator sizes, my 17th
century
timberframed house has been renovated as far as I can tell by replacing
all
the old wall materials with rendered breeze blocks. The walls seem to
vary
in width in different places, but the minimum seems to be 9 inches,
presumably solid breeze block. My attempts to google for a u value
haven't
been very successful. Can anyone suggest a reasonable u value for this
wall
construction that I can use in my calculations?

TIA

Keith
My guess is between 2 and 3
Chris
I would unhesitatingly line it intermally if possible
Let me know if you want a spec for this as I am doing this myself and
have developed quite a good system even tho i say it myself!
chris

There are loads of beams visible inside, so lining isn't really an option
without losing a lot of the character of the place. But thanks anyway for
the offer.

Even a thin layer of something insulating makes a considerable
difference in a solid brick wall.

Do no ignore the pssibility of external insulation, either.. If its
rendered outside, that is a distinct possibiliy.



Keith