# What Insulation should I use



## maryfitz (30 Mar 2011)

I'm planning on building a house and need advise on what type of insulation to use as half of my kitchen will be 2 stories and I've been told this can make it hard to heat. My architect said with the insulation available now it shouldn't be a problem, but I want to be able to specify a type when taking my plans to builders, I'd be delighted for any advice.

Thanks


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## horusd (30 Mar 2011)

Does the architect not recommend one and a specification? Check out seai.ie an the UK energy savings trust:http://www.energysavingtrust.org.uk/ 

 I used Kingspan and found them good, but its really down to the insulation qualities/properties rather perhaps than the brand.


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## Roamer808 (31 Mar 2011)

Architects will usually only spec what U-value the external walls need to achieve for regulations. There are a dozen ways to get the house insulated. Kingspan, Xtra Therm, Quinn all do foilfaced foam boards which is the best insulator to thickness ratio. Kingspan being considered the premium product. 

If the walls are double leaf, which they should be, then the builder will be putting 50mm cavtiy board in. What you put on the inside is upto yourself. But one thing I will say is insulate insulate insulate. You can never put too much insulation into external walls. I put 80mm backed plasterboard on all the outside walls here. And that is not even close to what A rated houses are insulated like. I just found a midpoint. Didn't want to be left with tiny rooms.
It's too late when the job is over to discover it's cold in the rooms.
Do be wary of anything 'new' and 'space age'. Some products on the market do not have an agrement cert. That's the magic bit of paper to say it has been tested by independent labs using a standardised test procedure. The foil blanket products are the major offenders.
If you ring or email Kingspan technical or send them a drawing and measurements they will give you all sorts of advice on how to do the job right. 
You might raise an eyebrow when you add up the costs of insulating to a high spec - I spent close to €3500 on materials alone doing my house. But I can turn off the heating quicker and the house stays warm for hours. Until herself stands yapping at the hall door.
and as for this BER cer stuff. I get a real sneaky feeling that is will become a form of tax in years to come. Lower energy efficient house, more tax. Cars have it already.
Your builder should be upto speed and pushing the best job for you. Plasterboard backed foil Kingspan is about €40-€45 per 8x4 sheet. It adds up quick. Good luck


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## maryfitz (31 Mar 2011)

Thanks a million thats great info, it's all a little over my head to start with but I'm sure I'll soon get used to it all.
Mary


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## threebedsemi (31 Mar 2011)

Roamer
A few queries I would have in relation to your response:
You say the walls 'should' be double leaf. I think that this is a bit of an overstatement when there are several other (and in my opinion in some cases better) systems out there at the moment, such as external wall insulation, single leaf timber frame, and so on, which are all worth considering.
Your comment that 'your builder should be up to speed' is in my experience sadly rarely true, an awful lot of builders dont have a clue about selecting or fitting insulation, nor do they have a basic understanding of building physics and the role of insulation in same.   

Maryfitz
I agree with Roamer808 that up to a point, you can't have 'too much' insulation. You should at this stage be getting your BER assessor to run through different levels of insulation for each element of your house (walls, floors, roofs) and giving you the heating load (i.e. the cost) for each option. You will then be at least in a position to estimate the payback period for different amounts of insulation.

The main point to remember is that any amount of insulation is worthless if it is badly or incorrectly fitted. Make sure you have someone supervising or inspecting your build who has a good grasp of this.

www.studioplustwo.com


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## Roamer808 (31 Mar 2011)

Sorry that most of the builders in your experience are not up to speed. The ones I deal with are. Double leaf is one way to build. Of course there are a dozen other ways. I'm just keeping it simple for the woman. Just how many projects are built with innovative techniques or methods?

Her architect I am sure who is not clueless will give her all the advice on building techniques if she wants. And I am sure she will check out the builder before signing up with them. 
Lady asked about insualtion - we could bang on for years about the quality of builders couldn't we?


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## eggerb (1 Apr 2011)

I found [broken link removed] Kingspan guide useful. They'll send you a hard copy in the post if you contact them.


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## horusd (1 Apr 2011)

As a bye the bye, I have the roof insulated between the joists with 300mm. Anyone know if there is an advantage in *also* inserting insulation directly between the joists under the roof or is this overkill?


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## Lex Foutish (2 Apr 2011)

horusd said:


> As a bye the bye, I have the roof insulated between the joists with 300mm. Anyone know if there is an advantage in *also* inserting insulation directly between the joists under the roof or is this overkill?


 
I presume, Horusd, that you're talking about doing something like putting insulated plasterboard on the ceiling, under the existing insulation and joists. It'd be of benefit alright as it'd prevent cold bridging, caused by the joists.


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## horusd (2 Apr 2011)

Lex Foutish said:


> I presume, Horusd, that you're talking about doing something like putting insulated plasterboard on the ceiling, under the existing insulation and joists. It'd be of benefit alright as it'd prevent cold bridging, caused by the joists.


 

Hi Lex, no, I mean directly under the roof and between the beams. I think it's a a layer if insulation board kind of thing with a silver layer. From memory Kingspan do it. I am wondering if, given I already have the 300mm of insulation between the joists, am I wasting money on considering this?


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## threebedsemi (2 Apr 2011)

horusd
If you mean insulating up the slope of the roof as well as having insulated on the flat, you will get better results by laying more insulation over the joists on the flat (in the opposite direction to cover the joists). There are rigid insulation boards with timber upper facings which are suitable for light foot traffic and light storage. This would also resolve the cold bridging issue with the joists which Lex referred to. 

You attic at the moment is a ventilated space, and insulating up the slopes throws up a lot of considerations regarding ventilation between the insulation and the roofing felt etc.

300mm roof insulation isn't bad by any means, if its well laid, and you may well get a better return on investment by looking elsewhere in your home for energy savings, such as draught proofing openings, etc.

www.studioplustwo.com


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