House insulation

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carrotcake

Registered User
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Hello, could I ask advice on what is the best amount of insulation to be put into house walls i.e. would partial fill of cavity wall with 60mm and dryline inside wall with 50mm be sufficient or what is recommended if I want a very well insulated house. Also would anyone have advice on whether to partially fill cavity or fully fill? I plan to build early in New Year but am getting a lot of my homework on building process done now! I am putting in geothermal underfloor heating and anyone I have spoken to about this has said that insulation is everything. Also with insulation for the underfloor heating, would 2 layers of 50mm kingspan be sufficient?

Also, how can one be sure that the house is airtight - I can say to the builder that I would like it to be but apart from standing over him and making sure it is (which is not realistic!), how else can I know?

Lastly, would anyone have recommendations on whether to go with timber windows or uPVC timber look windows and double or treple glazed? I read on a brochure recently that timber has a longer life than uPVC and that, 'despite common belief, UPVC windows do degrade, they are not maintanence free and cannot be repaired if needed'. Was thinking of putting in timber look uPVC but am unsure now...any advice would be much appreciated. Thank you!
 
Have you had a thorough read through You could also try giving them a ring for advice.

These two websites might give some further advice:

www.iaosb.com
[broken link removed]
 
Hi carrotcake,

Can't answer your question about insulation. But with regard to airtightness you can ask your builder to do an air tightness test, not all of them would do this but some do - this shows up where the are air leakages. With regard to windows would you not try aluclad timber windows - these are aluminium on the outside and wood on the inside. You can get them double or triple glazed with argon gas in between and a low e thermal coating.
 
As with everything money will be a factor. You should price up 50mm, 100mm and 25mm polyiso board, measure your walls and floors. Your in for a nice surprise about how much this stuff costs. If I'm correct your looking at between €10 and €15 per sq m at 100mm - depending of course on who buys it ie your builder or you.

When it comes to air tightness your looking at some sort of air changing unit and you should source that and using their guidelines on air tightness you can spec the builder on what you want done to achieve air tightness

Windows – money again. The cost of proper hardwood windows will blow you away. Also there are some limitations on the glazing (single, double, triple) that you can use with timber windows.The guys making these windows will run off quotes no problem so to put your mind at ease get the plans out there now. I imagine you will find timber far most aesthetically pleasing then any upvc out there, the frame should also be more energy efficient than pvc in that it passes less heat to the outside.
 
carrotcake said:
1. could I ask advice on what is the best amount of insulation to be put into house walls i.e. would partial fill of cavity wall with 60mm and dryline inside wall with 50mm be sufficient or what is recommended if I want a very well insulated house.
Click to expand...

carrotcake said:
2. I am putting in geothermal underfloor heating and anyone I have spoken to about this has said that insulation is everything. Also with insulation for the underfloor heating, would 2 layers of 50mm kingspan be sufficient?
Click to expand...

carrotcake said:
3.
Also, how can one be sure that the house is airtight - I can say to the builder that I would like it to be but apart from standing over him and making sure it is (which is not realistic!), how else can I know?
Click to expand...

carrotcake said:
4.
Lastly, would anyone have recommendations on whether to go with timber windows or uPVC timber look windows and double or treple glazed?
Click to expand...


1. you need to consider this in association with questions 2 and 3 as well. It is considered that 60mm partial fill 'kingspan' board meets the minimum regulation for wall insulation (0.27) {the true situation may be a lot worse however}...... If you want a true quantifiable u value of a wall, then i would not construct in double leaf cavity method. To be honest this method is almost outdated at this stage and this will become ever more apparent when the new regs come into effect next year... air tightness is not a strong point of cavity wall houses..... Blown-in polystyrene bead insulation will give you a better u value and will aid in the air-tightness of the building envelope.... Drylining on the inside will increase u values but is labour intensive.

2. you should ask the UFH suppliers what they recommend for floor insulation... i think 100mm of 'kingspan' would be ok. If you are putting in geothermal UFH then you need your build to be very airtight... do not put in passive or 'trickle' vents, you must incorporat a Heat Recovery Ventilation System. Personally i would stay a million miles away from cavity wall method if you are incorporating geoT with UFH... i would consider other methods like Poroton block, ICF or SIPs panel systems.....

3. short answer.. you cant.... Block houses by definition are draughty.. as i said above this will become all the more apparent next year when air tightness tests become compulsory...... (if possible, you should organise an air tightness test on a standard block build and see the results for yourself)

4. budget is the main factor here.... timber is sustainable as they are constructed in wood...uPVC is constructed from an oil residual product.... again check th emanufacturers spec and propose u values and mak eyou decision based on this...
 

Aren't the windows you refer to very expensive. If not who quotes them at best price?
 
sydthebeat said:
is the main factor here.... timber is sustainable as they are constructed in wood...uPVC is constructed from an oil residual product.... again check th emanufacturers spec and propose u values and mak eyou decision based on this...
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Aren't timber houses more noisy in terms of outside noise etc, than block ones. Also I know this is not relevant to the threat but you seem knowledgeable....should you concrete first floor or can you use sound insulation to do the trick with standard rafters etc...about €8k more to build cost and harder to organise the plumbing etc etc....
 

I can understand why people would think that timber frame houses are 'noiser' than block houses, but in truth its more ambigious than that.. it does all come down to standards and quality of construction and specification of materials. In theory the only difference between a standard TF and a block houses is the inner leaf is timber.... that shouldnt matter from an external noise situation... if anything internal impact noise is greater in TF than block....

anyway mickaeldes..... ive often said to clients that if i had a few extra quid during a build the very first thing i would do is install a concrete first floor...... never mind your paved driveway or granite worktop.... a concrete first floor is a huge advantage in a house... from noise and fire proofing.. and the general feeling of solidity under your feet....
the servicing shouldnt be considered difficult either... just remember to carry all the services under the floor ie inteh ground floor ceiling.... and in doing so remember to leave enough floor to ceiling height in the ground floor.....
 
Many thanks syd......my architect was of the same opinion on concrete flooring (forgo elsewhere to install it etc) - are timber frame cheaper to build in terms of these national companies...is it Kingspan subsid, and are they in the main good qual? My architect was not to up on them, as most res homes he does are block etc?
 
Thanks everyone for your really helpful replies - I do appreciate it - I will start getting quotes on timber windows versus UPVC and will also check up on airtightness test/cost of higher insulation etc. I will let ye know how I get on once I have got some prices etc. as the information may be helpful to others here on this website. Again, thanks very much for the advice - there is soo much to research/learn when building a house that it's almost impossible to get the time to look into every single factor so it is great to be able to get others advice/direction here. I'll come back with whatever useful information I pick up in next few weeks.
Regards, carrotcake.
 
MichaelDes said:
....- are timber frame cheaper to build in terms of these national companies...is it Kingspan subsid, and are they in the main good qual?.....
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im not entirely sure what you are asking me here michaeldes???

generally timberframe builds are not cheaper than conventional block..(usually they are around the same)..... and like anything in life you can have the Lada version or the rolls royce version..... budget is the main factor....

for me the Rolls Royce of timber frames is the Kingspan TEK build method.... (i have no association with this company, BTW, other than supervising a build where it was used....
 
Sueellen, thank you for those two websites names - the iaosb one has some very helpful information on it and I wasn't aware it existed until you told me - so many thanks. Regards.
 
Hi MichaelDes,

You refer to the aluclad windows as being expensive. It depends on what's important when building - to me I want to get the envelope of the house well insulated - my preference would be to use poroton block and aluclad double glazed windows with low e thermal coating and argon gas or crypton gas (more expensive). I have had various quotes for windows. There are a lot of windows in house all mainly on the south and south west of house. Ecoglaze do a lovely window - www.ecoglaze.ie but I found quote very expensive. The most competitive quote I got was from isothermal in newbridge - the windows are polish - [broken link removed] (think that's the correct address) the company is based in rathcoole. There is another company called nordan windows - the builder I am hoping to use got a quote from them in an around same price as isothermal. On my existing house here I added a sunroom 3 years ago and used Marvin aluclad windows - personally I wouldn't use Marvin again - the windows are lovely and look lovely but you can get better quality and cheaper prices if you shop around.

Hope I've been of some help
 

I was pleasantly surprised by the quote I got from www.ecolodge.ie . I too had gotten a quote from ecoglaze. The ecolodge quote was 18k cheaper for similar spec ( on paper at least ).
 
sas said:
I was pleasantly surprised by the quote I got from www.ecolodge.ie . I too had gotten a quote from ecoglaze. The ecolodge quote was 18k cheaper for similar spec ( on paper at least ).
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Hi SAS,

I'll have a look at the ecolodge windows. The ecoglaze was almost E20,000 in the difference than the two I've mentioned. Thanks for the name sas.
 
Hi Angela59 , your thread about windows was most helpfull to me also , I have submitted my plans to the vendors you mentioned ..!! , you mentioned poroton construction, are you referring to the poroton / paroc style or just insulating and plastering external and drywalling internally ?
very interested in the poroton construction style , but two many people/vendors saying thier way is the way to go !! too many choices makes only for confusion

thanks ............. MudHut
 

Hi MudHut,

[broken link removed] - Wolfgang is the person to talk to. FBT supply the weinberger poroton block. To fill you in a little - there are various types of poroton block, different sizes and different u-values and varying in price also. We brought our plans down to Wolfgang and asked his advice. The external of our house is part natural stone and part plaster. There is no problem using either stone or brick on the external of the poroton block, the external plaster has to be a breathable plaster recommended by FBT, it is was normal plaster there could be cracking or it could pull away from the block. This plaster only comes in off white but you can paint over so long as paint is water based. Using external insulation is not recommended on the poroton even though I have seen it used. I think in a very severe climate you can do this but our climate is mild. My main concern would be that the house breathe in winter and also summer. Poroton block is not cheap but because it is a single leaf layer this cuts on labour and again because it is self insulating no insulation costs apart from floors and roof. What you loose on the roundabout you gain on the swings. Hope I've been of some help but to get the exact technical date get on to FBT, Finnoula and Wolfgang are very helpful. I have no affiliation to FBT just very pleased with their help and advice.
angela59
 
Thanks for info Angela I have actually being in contact with FBT, and their brouchere arrived yesterday..!! so I will have a good look thru it , Also I read on this board about people having problems as regards hanging fixtures or securing hook points to the poroton , that it is a not capable of supporting the weight , or becomes too brittle , do you think there is any truth to this or just isolated incedents ? sorry for chewing your ear off ...!! thanks again............... MudHut
 
Hi Mudhut,

With regard to the fixings, it would be a concern of mine also and there was a thread going back a while on this but again you can get fixings suitable for this type of block - not sure how expensive.
 
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