Insulation in 1980s built house

Johnsee

I was looking at upgrading the internal wall insulation on my 3 bed semi D in Dublin. It was built in the 1980s. The internal (single block) walls currently have polysterene backed plasterboard (to a dept of 50mm (dept of plasterboard and insulation) on the internal walls.

Can anyone tell me if removing this board and ugrading to an up a newer plasterboard with say 12mm with 50mm insulation (total 63mm) attached will make much of a difference from the old polysterene one? W/mK values??

Should I go for more than 50mm insulation and can anyone recommend a specific board Kingspan/Quinn...whover???

MicktheMan

How's your air tightness?

Johnsee

Never had a survey done but from what I can see, PVC windows seem ok, no obvious electrical or plumbing leaks, all rooms vented, walls in reasonable condition, north west-facing rooms are cold though...

cpoh1

MicktheMan wrote: »

How's your air tightness?

Hi Mick,

Completely see where you are coming from when you talk about air tightness but unless there is something obvious like really old poorly sealed windows/doors, holes in the roof etc. then pursuing air tightness in an older home is cost prohibitive to say the least.

As an engineer I was chatting to about my own work recently commented "it would be cheaper to knock the house and start again than to retrofit an existing house and get the required air tightness of a modern build".

It would be wrong to send people solely down the air tightness road without understanding the role it plays overall. Go for the easy air tight wins and then look at your insulation is my advice.

MicktheMan

Johnsee wrote: »

Never had a survey done but from what I can see, PVC windows seem ok, no obvious electrical or plumbing leaks, all rooms vented, walls in reasonable condition, north west-facing rooms are cold though...

You're looking for advice on upgrading your internal wall insulation which will mean a lot of disruption internally with dubious benefit, on an internet forum, yet you have not had an independent survey or test carried out on the house to ascertain exactly where your heat is being lost

Take my advice and have the house tested.

MicktheMan

cpoh1 wrote: »

Hi Mick,

1.Completely see where you are coming from when you talk about air tightness but unless there is something obvious like really old poorly sealed windows/doors, holes in the roof etc. then pursuing air tightness in an older home is cost prohibitive to say the least.

2.As an engineer I was chatting to about my own work recently commented "it would be cheaper to knock the house and start again than to retrofit an existing house and get the required air tightness of a modern build".

3.It would be wrong to send people solely down the air tightness road without understanding the role it plays overall. Go for the easy air tight wins and then look at your insulation is my advice.

1. In the case of the OP it may not be. There is a hell of a lot of other opportunities to improve air tightness than those listed by you.
2. BS. It goes to show the level of ignorance there is out there on the subject. Of course, this level of ignorance doesn't do our insulation companies / industry any harm:rolleyes:
3.I would much prefer to live in an airtight and appropriately ventilated house with moderate insulation than an air leaky but super insulated one.

cpoh1

MicktheMan wrote: »

1. In the case of the OP it may not be. There is a hell of a lot of other opportunities to improve air tightness than those listed by you.
2. BS. It goes to show the level of ignorance there is out there on the subject. Of course, this level of ignorance doesn't do our insulation companies / industry any harm:rolleyes:
3.I would much prefer to live in an airtight and appropriately ventilated house with moderate insulation than an air leaky but super insulated one.

Mick, I got three quotes before we started our work and the level of cost required to bring our house to the level of air tightness for a new build was scanadalous. In the end we settled for basic airtightness opportunities (we were replacing windows anyway) and a decent level of insulation.

Your point 3. is basically agreeing with what I wrote, get the big wins for airtightness sorted (windows/doors, holes in ceilings etc.) and get a decent level of insulation installed.

Cost benefit starts to get really tenuous when you go down the white rabbit road of looking at air tightness beyond sealing basic opes and draughts.

cpoh1

MicktheMan wrote: »

You're looking for advice on upgrading your internal wall insulation which will mean a lot of disruption internally with dubious benefit, on an internet forum, yet you have not had an independent survey or test carried out on the house to ascertain exactly where your heat is being lost

Take my advice and have the house tested.

Would question that comment Mick, I know you have an angle being in the industry with air tightness but dry lining walls DOES make a difference!

Johnsee

Thanks to Mick and Cpoh for your advise. Will look into having a survey done.

Can you answer one thing if you can, is the modern insulated plasterboard (for example) something like "Xtratherm XT/TL(MF)" much more effecient in heat retention W/mK than a polysterene backed insulated board of the same thickness installed in the 1980s....tnks

sydthebeat

Johnsee wrote: »

Thanks to Mick and Cpoh for your advise. Will look into having a survey done.

Can you answer one thing if you can, is the modern insulated plasterboard (for example) something like "Xtratherm XT/TL(MF)" much more effecient in heat retention W/mK than a polysterene backed insulated board of the same thickness installed in the 1980s....tnks

probably about 40% better

however when you take into account all the thermal bridges involved in internal insulation, the overall effectiveness of any layer of any insulation reduces by about 30% anyway

MicktheMan

cpoh1 wrote: »

but dry lining walls DOES make a difference!

Not if those same walls are leaking air like a sieve!