Insulating Advice

dub_dan

Hi All,

Looking for all advice, suggestions.

Have just bought a 2nd hand house, 4 bed bungalow with approx 1400sqft.

We have replaced all windows in the house, triple glazed some of them depending on the room location/size and double glazed the rest.

Now I would like to make the house better at retaining heat.

The exterior walls are cavity block so pumping them with insulation is out.

A friend has suggested we take down all plasterboard/old insulation/all battons attached to exterior walls and replace it with 100mm kingspan insulation board held to the wall with steel mushrooms. (Is it ok to bolt these boards straight to the wall?)

There is fibreglass insulation in the attic but it is old so I am thinking of topping that up also with thicker matting.

I'm a complete novice when it comes to this type of work so looking for some advice with it.

Cheers,

Dan

Johny 8

Sounds like its gona be warm! Cosy winter!

BryanF

dub_dan wrote: »

Hi All,

Looking for all advice, suggestions.

Have just bought a 2nd hand house, 4 bed bungalow with approx 1400sqft.

We have replaced all windows in the house, triple glazed some of them depending on the room location/size and double glazed the rest.

Now I would like to make the house better at retaining heat.

The exterior walls are cavity block so pumping them with insulation is out.

A friend has suggested we take down all plasterboard/old insulation/all battons attached to exterior walls and replace it with 100mm kingspan insulation board held to the wall with steel mushrooms. (Is it ok to bolt these boards straight to the wall?)

There is fibreglass insulation in the attic but it is old so I am thinking of topping that up also with thicker matting.

I'm a complete novice when it comes to this type of work so looking for some advice with it.

Cheers,

Dan

as regards the walls:
id have a read of this
http://www.josephlittlearchitects.com/documents/Breaking_the_Mould_1_Construct_Ireland_Issue_6_Vol_4.pdf

its a pity you didn't look at insulation when installing the windows, as its difficult to achieve an insulation overlap when their already installed..

as regards the attic: make sure there is space retained at the eaves to allow the roof to ventilate properly.

you mayalso want to revsit your internal ventilation strategy especially with new windows, are there window vents or wall vents?

Merch

I came across joseph littles documents previously completely by accident when looking up insulation.
Pages 3 and 4 have some good points regarding condensation/dew point and what is as important as heat loss, which is managing the moisture content in the building. I think this needs to be modelled by computer and I'm not sure if access is available to something like that reasonably cheaply?? I tried DEAP for heat loss myself and I gave up on it.

Either way you need some accurate figures on what the values of thermal resistance or heat transmittance are for the materials used in any existing construction.

After reading up on a few of the articles, I'm more convinced that its better to NOT improve my insulation than to do it wrong, hopefully I'll have figured something out by the time I can get around to it.
In an ideal world, it'd be external insulation/minimised thermal bridges at doors and windows/heat,ventilation recovery. All thats going to cost and its out of my range at the minute, plus as the house is built, much of it cannot be done (maybe not even allowed) as it would change the look of it compared surrounding/attached houses.

again, after reading a few of his articles
I'm more convinced to external insulation than internal, as I'm concerned about reducing the temperature on the internal side of the blocks as this would reduce the temperature at that point and cause the dew point temp to be reached more easily.
having said that, internal would be the cheapest route if i can figure out the dew point across a range of temperatures and relative humidity.

I'm a bit wary of current installers of external insulation as Im uncertain if any of what they are doing is measured for its effectiveness (what the benefits in savings are compared to the instal cost), as I've heard the cost for this is high, then it'd need to be a bit more than slapping up some insulation,membrane and rendering it.

Anyone any pointers on figuring out the temperature on the internal side of a construction (dew point) when installing internal insulation over existing dry lining.
I'm looking at making even a moderate improvements in retaining heat, while not creating the conditions for mould (health/structural damage) at a cost effective price!

ShiresV2

Merch wrote: »

Anyone any pointers on figuring out the temperature on the internal side of a construction (dew point) when installing internal insulation over existing dry lining.
I'm looking at making even a moderate improvements in retaining heat, while not creating the conditions for mould (health/structural damage) at a cost effective price!

This software has a 30 day trial and does condensation risk analysis among other things. I think it's worthwhile noting that it is of course just a "best guess" by software and doesn't take into account all factors, for example the standard of installation.

http://www.builddesk.co.uk/our+software/builddesk+u

Merch

ShiresV2 wrote: »

This software has a 30 day trial and does condensation risk analysis among other things. I think it's worthwhile noting that it is of course just a "best guess" by software and doesn't take into account all factors, for example the standard of installation.

http://www.builddesk.co.uk/our+software/builddesk+u

Thanks, I've just been thinking about it again, when I have time in between other things.
Im not sure if I saw this last post at the time or if it just went to the backburner, I know I made enquiries here on boards regarding insulation going back a good while, there are different reasons for it not getting going but I really wanted to wait and see if I could model different insulation and installation types and see their effects on moisture and heat loss. I wont try the above software due to the trial date running out until I have time to look at it.

I wonder why people are getting insulation (usually external) done, without knowing what the effects of it are or measuring the potential savings. Although Im sure there is some saving to be made, there are finer points which I think are not addressed by getting external (any) insulation work done.

While its probably better to use the software for this, re the trial time limit, I'll just ask for the moment.

I was thinking about installing insulation internally over plasterboard, but am concerned about trapping moisture between the existing plasterboard and the inner side of the cavity block walls.

I began to think, if I removed the existing plasterboard and bonded the new insulated plasterboard directly to the inner surface of the block construction, that I would save some depth (not a major requirement, except for small rooms) but that it would improve upon the existing layer of a plasterboard airspace and also (mostly) possibly prevent a place where moisture could get trapped and cause mould growth.
Is this likely? it would push the temerature gradient down steeply just outside the insulation, but there would be no airspace for mould to exist and grow nor anywhere for extra mositure to exist and condense on the internal block surfaces.

My concerns are,
if just insulated over existing plasterboard
that the warmest part of the wall cross section after the insulation will still transmit enough heat to the coldest part of the internal block face where moisture in the space could condense there and cause mould growth.

It should depend on the outside air temperature, wind speed and humidity whether mould spores can grow??

Id be more concerned during warm weather as the RH would be higher although the temperature difference would be less between inside/outside so there would be less reason/opportunity for moisture to condense on cold surfaces.