solid wall insulation

[stormtroupper]

solid walls need insulate -
my flat over looks river and is cold but not damp .
my rented house had black mould for the first time on north facing walls above skirting board below windows in bedrm 1 rm -behind bed and the other behind curtains. its been cleaned and not returned as I sugested better ventatlation and more heat.
clearly I still need to get to root of problem .
most of the walls are windows but can I still dry line .
and can I use a flexable sheeting or do I need to plaster board as well.
I was shocked just how damp the walls are in bedrooms can there be another reason why - there no damp marks.

thks - damsel in distress

 

[alittlerespect]

Hi

It is highly probable that one of the problems you are having is a lack of air circulation, rather than ventilation - behind wardrobes etc which meant the hidden areas of walling were getting colder and any warm air that does find its way to these areas of walls will reach its dew point (warm air holds more moisture than cold air and when the warm air meets a cold surface the air temperature drops and what was the warm air can no longer hold the moisture and hey presto you have surface condensation.

It may be that the rented house costs so much to heat that occupiers cannot afford to have the heaters on all day and all night, and where the heating is put 'on and off' all day long it will aggravate the conditions as above where warm air meets a cold enough surface, surface condensation will occur - which is why windows are the first sign of a problem, as glass is so poor at providing any real thermal resistance that it is generally the first point where surface condensation occurs - the walls having slightly better thermal resistance don't have such a problem with condensation, but conditions can easily get to the level's that you are experiencing.

Solution - you may not be agreeable, but I will still make it as a suggestion: stick 25mm bitumen impregnated felt in small sections say 75mm wide by 200 long onto walls at correct spacing and stick insulated plasterboard panels to the felt dabs. Possibly need an insulation thickness of 80mm on 12.5mm plasterboard and skim coat of plaster to finish: this will give you an insulation U value of around 0.25 to 0.3 W/m2C compared to the original U value of 2.1W/m2C for solid walls in normally exposed areas.

Others may have different solutions to your problem, but at least the above will provide you with an indication of what is achievable.

 

[stormtroupper]

many thks - sounds excellent advice .

 

[stormtroupper]

whoops - what do you mean by small sections .... onto walls at correct spacing - what is correct spacing ? sorry if that a silly question ?

 

[alittlerespect]

Hi

Damson in distress!! I have done a sketch for you - on the basis that one picture is worth more than words alone!!

Other people may have other idea's, but the solution means that the insulated panel is not fitted directly to the cold/damp wall which would otherwise affect the performance of the installation.

I have done some calculations, which I thought might interest you. The existing wall has a U value of 2.1W/m2C and looses the equivalent of 114kWh of energy per square metre of wall area. The proposed solution would reduce this energy loss down to a mere 12kWh of energy per square metre of wall area (that is on a cold day where the temperature difference between the outside and inside is 15 degree's C) the wall will than have a revised U value of only 0.22W/m2C (impressive don't you think?)

From a sustainability perspective the saving in energy consumption of 102kW is equivalent to a reduction in CO2 emmissions of 53kg/kWh.

One final note: You could reduce the insulation thickness to 50mm and this would give you a revised consumption of 17kWh/m2 and a U value of 0.31W/m2C.

Regards
GJ

Insulated Wall

• alittlerespect
• 28 Feb 2009
• 1

 

[alittlerespect]

Humm! typical the spell checker did not pick up the grammer mistake!! Just shows one should not rush in to impress!!

Regards
GJ

 

[stormtroupper]

Gosh that is impressive - thank you so much for taking the time to explain .
and what a saving - I see on Planet insulation they have a home table - of savings according to them - duble glazing at a cost of 4000 pounds would take 97.6 years to recoup with a 26 kg carbon saved each year ! sounds like you save me a fortune in money, and greatly reduced my carbon footprint . thank you .

now for the big question - do you know if there's a solar power method that can ran an AC in extreme hot climate - like the middle east Dubai .
being doing some googling and not found much ?

 

[alittlerespect]

Apologies for not getting back to you sooner - I feel like I have had a week (or could easily be more of information overload, more to do with work than anything else!)

I should explain that the figures that I previously provided represent a bad case scenario in that I took the outside design temperture as 0C and the internal temperature of 15C this is slightly less than the differential used in design of buildings where the average minimum external temperature is -1C which would have given a temperature differential of 16C rather than the 15C that I used which would mean that the energy loss through the external walls would be slightly worse, however, the figures do provide an approximate idea of the energy loss that can occur. You also need to be aware that when the external temperature is at 15C (this is the design temperature where theoretically there is no heat loss from and no heat gain to the building. The point that I am trying to get across is that as the external temperature rises so the energy loss through the walls is reduced, as are the cost benefits, which will have an impact on the payback period for the project.

I have not been on Planet Insulations website - but I assume they have a similar calculator for the payback period for wall insulation, if so, it would be worthwhile checking out which is the better payback option - 50mm or 80mm urethane insulation. My choice would be urethane for the insulation material as it has the benefit of being vapour resistant and saves the need to introduce a vapour barrier into the design for cladding the external walls.

I have carried out a short search on google and have come up with the attached sheets, which may be of interest to you. One is an article by BSEE which gives a useful head's up on the current benefits of PVs. The others two sheets are systems currently available, which may or may not be of interest to you.

Regretfully, net has given codes that don't relate to the titles so I am assuming that the article by BSEE is the middle file!

Regards
GJ

Untitled

• alittlerespect
• 4 Mar 2009
• 1

Untitled

• alittlerespect
• 4 Mar 2009
• 1

Untitled

• alittlerespect
• 4 Mar 2009
• 1