Hi
I am thinking of getting my lean to consevatory updated. I would like
to be able to use it for more of the year - at present it is no good
from late September onwards - too cold. It is only single glazed, and
has brick sides so the only glass is the roof and front, which is all
glass with a sliding patio door.
Just considering the options for the change - thinking of hardwood.
Should I go for a low brick wall or keep it all glass? Which is best
for winter use?
Thanks for any advice you can give!

On 2007-02-16 14:11:52 +0000, "Mikeyboy" said:

Hi
I am thinking of getting my lean to consevatory updated. I would like
to be able to use it for more of the year - at present it is no good
from late September onwards - too cold. It is only single glazed, and
has brick sides so the only glass is the roof and front, which is all
glass with a sliding patio door.
Just considering the options for the change - thinking of hardwood.
Should I go for a low brick wall or keep it all glass? Which is best
for winter use?
Thanks for any advice you can give!

In terms of heat loss you can reduce that by going for double glazed
roof and wall/door.

That will be the main part. Going for a low brick wall will only make
a difference to the extent
of the area of that. If you are getting up to the height of a
window as in a normal room window,
you risk exceeding the limit for what is allowable for a conservatory.

This is that at least 50% of wall area and 75% of roof area is
translucent material (i.e. glass or horrible polycarbonate)

Beyond that it becomes an extension and is subject to building and
planning controls and you may not want to bother with that so you will
need to measure and check existing wall areas as you may already be
close to the limit.

If you are going to add heating, then there must be separate controls
for it to those for the house.

In any case, the door and any windows from the main house need to be
equivalent to exterior
versions in terms of insulating properties - i.e. not knock-throughs

The existing walls (2 sides, rear) are part of the house - it is based
on an original Victorian conservatory. Nothing new is planned, merely
updating of a rather out of date design. Are you saying that the dwarf
walls won't add to the heat-retaining qualities? Even if insulated to
the max?

Mikeyboy wrote:
Hi
I am thinking of getting my lean to consevatory updated. I would like
to be able to use it for more of the year - at present it is no good
from late September onwards - too cold. It is only single glazed, and
has brick sides so the only glass is the roof and front, which is all
glass with a sliding patio door.
Just considering the options for the change - thinking of hardwood.
Should I go for a low brick wall or keep it all glass? Which is best
for winter use?
Thanks for any advice you can give!


Hi Mikeyboy,

Having finished my self build dwarf wall conservatory just before
Christmas (had the parts delivered April 2005 but but then I am a slow
worker but did promise the wife that we could have Port and biscuits in
it on Christmas day)
I fitted underfloor heating (from Screwfix) with tiled floor and walls
and 2 twin 13a sockets.
Looked at full length Conservatories but considered they looked too much
like a greenhouse, already got one of those.
The dwarf wall done in the same brick as the house is more
anaesthetically pleasing

During a cold spell in January the underfloor heating (150w per square
metre) kept it to about 13c when outside it was below freezing, have a
convector heater to boost the temperature when needed.
The insulated cavity wall will make a difference to the heat retention.

It all boils down to the fact that glass is not a good insulator so less
is better for warmth but less glass less light, a dwarf wall system
gives you a bit of both

Bazza

On 2007-02-16 16:25:59 +0000, "Mikeyboy" said:

The existing walls (2 sides, rear) are part of the house - it is based
on an original Victorian conservatory. Nothing new is planned, merely
updating of a rather out of date design. Are you saying that the dwarf
walls won't add to the heat-retaining qualities? Even if insulated to
the max?

They will do, but calculate the areas and heat losses using U values
for the surfaces

You can find tables of U values or programs on radiator manufacturer
web sites or
in the Approved Docs to the Building Regulations.

The calculation for a given surface is to multiply the area in square
metres by the U value and
the temperature difference. When you are doing this for calculating
radiator sizes it is
typical to assume -3 degrees outside and 18 or 21 according to taste inside.
Clearly the larger the U value the worse the insulating properties.

Out of what you have, it is likely that the largest heat loss will be
the current glass because it is
single and has a very large area. If the existing walls are single or
double brick with no insulation,
then they will be next, followed by the floor.

Practically, you probably wouldn't do anything about the floor unless
you want to dig it all up, put in a sheet
of polystyrene foam 100mm thick and concrete, or create a floor above
the existing, on joists, insulate it and board over that.

You could add dwarf walls insulated to modern standards and make some
difference vs. having them as all glass.
However, unless the area is substantial, the effect will be minor in
the context of the overall room. that's why I said that to make a
large overall difference you would need to have these walls larger as a
proportion of the whole and then you run towards being outside the
definition of a conservatory and subject to Building Control.

Certainly the type of glass is the one to go for first.

If you don't mind losing some overall size, you could fix studs to the
existing walls, put in Celotex sheet (has 3 times insulating properties
of glass wool for a given thickness)and fit plasterboard over that.
This would take you to modern insulation standards for walls. It is
likely that this would be the second most significant loss of heat
after the roof and glass walls and door.

Whichever way, you need to do the sums to know what you are dealing with.

Thanks Andy and Bazza for your advice. It is very helpful, and has
given me plenty of food for thought.
Cheers.