underfloor insulation

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8043 posts

Uber Geek

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#569446 16-Jan-2012 13:56

Though good luck if you are on a community services card. In the Manawatu there are 10 providers if you aren't after the community services extra discount. Select yes I have a card and that number magically drops to only 2-3 providers. That's pretty shameful.

People I know finally got a call 2 - 3 years after they had applied (with a community services card) in Palmerston North, by which time they had sold the house and moved on.

That said if you are going to pay someone to do it then the grant scheme is excellent given you'll get some assistance. If you were going to DIY then maybe you'll get it installed for free sort of thing.

To be honest I think insulation (especially ceiling) should be checked afterwards with a thermal imaging camera. If that's not being done then honestly how do they know they have done a sufficient job?

Jaimita

15 posts

Geek

#569447 16-Jan-2012 13:57

Be careful with rigid products such as polystyrene because they are hard to get the shape right and it's very easy to get gaps where less rigid products can be squeezed and molded better into gaps.

Jaimita

15 posts

Geek

#569451 16-Jan-2012 14:01

Insulation providers from the scheme are being audited which means they get EECA auditers checking houses they have insulated providing some assurance to homeowners it is done right.

Byrned

455 posts

Ultimate Geek

#569482 16-Jan-2012 14:56

I looked at doing the insulation myself, but in the end got someone to do it. With the EECA money you get from an approved installer doing the job, that makes the labour free.

The hardest part then was working out which product to go with. Stayed away from Expol due to the R value compared to the cost of the product + installation. From memory it is an R value of 1.4 compared with most of the "wool" type products starting at 1.5 and up.

jaymz

1133 posts

Uber Geek

#569484 16-Jan-2012 14:59

Jaxson:

Very good point though about ensuring the ground is covered with plastic sheet. If that's not there, and ground seems a bit moist, that should be the first point of call. Also can make it a lot easier to move about too! If the ground is wet, try working out why whilst you're under there too.

+1 for this. Under our house the dirt was damp (not wet but defiantly not dry)

Last year i installed black polythene directly over the dirt under the house. It cost me $100 for a 25m by 5m roll of nice thick stuff.

I stapled it to the side boards under the house and joined the sections together with tape.

It made a HUGE difference to the house, it was much warmer and feels drier that before. The house already had the foil based insulation under it, and with the removal of the moisture from the dirt, i feel there is no need for further insulation under the house.

I checked under the plastic a couple of weeks ago, and there was a lot of moisture stuck to the underside of the plastic, so i know it is doing it's job!

What is the condition of the dirt under your house? if it is damp i would moisture proof it before investing in insulation.

Jaimita

15 posts

Geek

#569492 16-Jan-2012 15:22

The plastic for on the ground is called polythene sheeting, and also qualifies for subsidies under the EECA scheme. Moist air is harder to heat so that's why it is a good idea in areas where soils are damp.

shaopu

111 posts

Master Geek

#569499 16-Jan-2012 15:30

Great to know about the polythene sheeting, i will check tonight and see the condition of the dirts..so do you simply laying the sheetings onto the soil area?? cheers

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Jaimita

15 posts

Geek

#569502 16-Jan-2012 15:34

It may be dry in summer but not in winter so when it's dry now don't assume it is ok. Look out for tell tale signs such as mould, mushrooms growing under the house, although some soil deposits can look like mould but aren't so can be tricky.

jaymz

1133 posts

Uber Geek

#569504 16-Jan-2012 15:40

shaopu: Great to know about the polythene sheeting, i will check tonight and see the condition of the dirts..so do you simply laying the sheetings onto the soil area?? cheers

Pretty much, the idea is to create a sealed barrier over the dirt.

I laid the plastic over the dirt and stapled it to the lower boards along the side of the house (closet to the ground) then sealed the joins with tape

It doesn't have to be perfect, but the less gaps and holes the better.

I will take a photo tonight and upload for you.

shaopu

111 posts

Master Geek

#569508 16-Jan-2012 15:54

thanks!!!!!!!!!

Regs

4066 posts

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Snowflake

#569528 16-Jan-2012 16:35

shaopu: Hi everyone, we just bought a 50s old house with timeber floor, i am planning to do the underfloor insulation by myself and really would like some advises: (BTW, i am in hillsborough Auckland)

1: what material woudl be the best suit? from both cost, effectiveness, insatllation difficulty perspective.

2: which suppliers would be recommended?

3: i have done my celling on my previous house before and this one does have the celling insulation done already.. i have never done the underfloor one and i hope it would not be too hard..i have heaps of rooms downstaires. any previous DIY experience/tips to share would be great!!

4: wonder if it would be the same cost if i get someone to installed it with the subsidies as i beliebe my house does qualify for the government subsidy..

thanks in advance and love Geekzone as i always receive highest quality help and answers...

with the subsidy you can basically get free installation.... note that you need to have your ceiling insulation up-to-spec before you get subsidy for underfloor.

i used www.underfloor.co.nz for my ceiling top-up and underfloor insulation install. can recommend them. i went with their higher r-rated product = cocoon r2.6

we also have a timber floor and it made a huge differenc to floor temperature and heat retention (and therefore heating costs). highly recommend doing it.

Sales Engineer
Snowflake
www.snowflake.com

about.me/nzregs
Twitter: @nzregs

Regs

4066 posts

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Snowflake

#569531 16-Jan-2012 16:39

SaltyNZ:
Jaxson: Foil doesn't get the official nod:www.energywise.govt.nz

Foil by itself doesn't meet Building Code requirements where it's formally deemed that underfloor insulation is required. www.waitakere.govt.nz/abtcit/ec/bldsus/pdf/energy/insulation.pdf

For $200 though it's better than nothing. It all hinges around creating an air type gap, just the same as double glazing. In practise this takes quite a bit of effort and thought to achieve. Watch you don't electrocute yourself either, that's not cool.

When we did it about 2.5 years ago it was acceptable in the Rodney district as underfloor insulation. Interesting to see where the Supercity sits on it.

As far as not stapling your wiring... I would have *thought* that went without saying. :-)

EECA doesnt give it the nod for subsidy, but i think its still meets the requirements under the building code - at least it did when we did some renovations to our house a couple of years back.

Foil only gave an R value of 1.1 though, so you're much better off using a better product - *especially* with timber floors

Sales Engineer
Snowflake
www.snowflake.com

about.me/nzregs
Twitter: @nzregs

graemeh

2078 posts

Uber Geek

#569541 16-Jan-2012 16:56

Regs: i used www.underfloor.co.nz for my ceiling top-up and underfloor insulation install. can recommend them. i went with their higher r-rated product = cocoon r2.6

we also have a timber floor and it made a huge differenc to floor temperature and heat retention (and therefore heating costs). highly recommend doing it.

+1

We used the same product and also have timber floors. It made the house much easier to heat and keep warm.

The product is also easy to install (as easy as it can be crawling around on your back under a house) as it goes from bearer to bearer so you end up doing about 1.5m2 with each piece.

When I was stapling near cables I would put one hand over the cable, that way I knew if the stapler was ever close to the cable. I did not staple my hand (or any cables).

jaymz

1133 posts

Uber Geek

#569555 16-Jan-2012 17:37

shaopu: thanks!!!!!!!!!

As promised, here are the photos from under our house.

It makes moving around under the house so much easier, and cleaner!

I got the polythene from Mitre10Mega in the trade supplies section.

timmmay

20587 posts

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#569572 16-Jan-2012 18:31

Polythene under the house, properly pegged down, can do wonders to stop rising damp. It has to be pegged everywhere, and taped to piles.

I have a blanket type insulation under my house, I got some kind of grant to do it. Not sure how much difference it made, but my floor boards fit together well and I have carpet. I would like to put that silver foil in, in addition to the blanket stuff, and I may pay someone to do it one day.

If I were doing it now i'd want something that both sealed (like foil) and insulated (like a blanket).

Other than stopping damp, i'm not sure how much difference it made. Adding pink batts on top of loose fill wool insulation made a much bigger difference to keeping the house warm.

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