Ground floor insulation

Hi,

We've just started building our house in Cork - horray!. When we initially went to our builder to talk about insulation, among his recommentations were 60mls of Kingspan on insulation on the ground floor. Now the builder has come back to us as is saying that a few of his other customers are putting in 100mls on the ground floor. I've just got off the phone with Kingspan who didn't prove that helpful - all they said was that the U-Value is improved up to 30%. For an extra cost of around €1000, is this increase in insulation worth it? Bear in mind, we are being generous with the insultion already around the house as well as planning to install good u-value windows. I guess we are a little fearful that we are going to hear about all these other things that would be better, resulting in our house budget going way over. Don't get me wrong, we're not scrimping, we have done a lot of work on insulation and other areas and will put the money into the right places, but we don't want to be taken for a ride either. All comments helpful Thanks.

i wouldn't put any less than a 100mm on a ground floor, either, but that's just me........... I have 150 in places!! 2 layers of 50mm, staggered joints is good.

And, you're not confined to Kingspan, btw. Try Aeroboard, Litepac, Airpac, Dow Floormate etc etc .....the list goes on !!

A thousand euro won't fill the average domestic oil tank (at 1000 litres each fill) twice, which is the average amount of oil that's used by the "average" household in a year. If it were me I'd bump up the insulation; energy costs are rising all the time and there will never be a cheaper time to do this. Anyone building a new house from scratch should be looking at optimising insulation and incorporating any other proven energy saving measures where possible; the extra over cost incurred now will look cheap in 5 years time.

bump up the insulation but use other brand like hytherm or aeorboard which give similar uvalue for alot less money

Thanks for your replies. All points are valid. However, a point that's niggling at me is that heat rises - so why is it a thing that extra insulation is needed at ground floor level.

Also, at present the regs are 60mls - do you believe that this will change soon to 100mls being the reg?

Sparki74 said:

Thanks for your replies. All points are valid. However, a point that's niggling at me is that heat rises - so why is it a thing that extra insulation is needed at ground floor level.

Also, at present the regs are 60mls - do you believe that this will change soon to 100mls being the reg?

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Regs will most definitely change as EU harmonisation continues; some countries are already achieving far higher standards than our own in terms of insulation and energy performance. Heat does rise but a cold floor does impact on the effectiveness of your space heating and heat losses. A well insulated floor reduces heat loss but also contributes to comfort and this is very important.

Thanks eveyone for your replies. We've made a decision to go with the 100mls. Cheers

Another thing to bear in mind is that all homes to be sold or rented, both new homes and existing ones, will soon need to have a BER (Building Energy Rating). The depth of insulation you use throughout the house will have a key impact on your rating. In theory (and hopefully in practice) this will increase the value of your house.

J2K

price 125mm aerobord/springvale floorshield i found it a lot cheaper than kingspan.ring the factory in co.cavan and ask for seamus he gave me all the info i needed and prices and would do a deal maybe

Jumping in here for some info from you guys as you all seem to know a lot about this. I have posted recently about new extension at the back of house but want to build something really warm, energy efficient etc so am trying to find out what is best. No building experience but FIL is doing build and want to be able to go to him with my own suggestions.
Area is 14ft x 24.5ft, sloping roof with skylights x 3 big ones, wooden floor and 2 large ceiling to floor trifold double glazed doors across the back
What is best ecofriendly and most efficient stuff to insulate the walls and floors with?? Not too concerned about costs. Husband is taking about underfloor heating but that sound like a luxury that can't be that energy friendly, am I right or wrong?? Is there a website where I can learn some stuff??
Would appreciate any info as am blond girl in big builders world...

For what it's worth, here's my tuppence worth:

1. I don't think it's worthwhile or cost effective to incorporate UFH in an extension unless you're also planning extensive modifications and upgrades to your entire plumbing system anyway. Is it really necessary either, UFH is very comfortable but doesn't offer a quick response time which is a problem in our changeable (four seasons in one day) climate.

2.Plan your extension to maximise on solar heat gain, if possible. Use high performance coated double glazing window units which retain heat better and allow you to benefit from solar heat gain in the winter months.

3. Incorporate a solar panel in your new roof and upgrade your domestic storage cylinder.

4. Use insulation products which meet or exceed current building regulations. Use higher performance roof underlays (breathable membranes) and cut down on losses through infiltration.

5. Avoid PVC where possible- its environmental credentials are woeful, use anything else- timber and aluminium are both sustainable.

6. Give your plumbing and heating system a makeover- fit TRVs on old rads, fit motorised valves and other zone controls.

7. Improve the lighting and controls in your entire house.

8. Plan an outdoor area or patio to complement your new extension and make it an integral part of how you plan the extension and use it.

9. Incorporate some storage space in the new attic space with a ladder access, where possible.