Help Insulation advice needed!

Forums › Home Workshop DIY › Help Insulation advice needed!

Klysznz

8 posts

Wannabe Geek

#296216 30-May-2022 21:22

Hi All,

Working on making my newly purchased 1930s bungalow more energy efficient and have a few questions about insulation (Particularly underfloor insulation).

Being a old house, at some point it has been extended resulting in difference ground clearances, any way I had a consultant from Brightr come and quote. Part of the house was too low to be insulated (29cm between ground & bearer) so was quoted $1,623 for ~42sqm of Underfloor insulation (Mammoth R1.5) and a Moisture Barrier where this could be installed (this would leave ~90sqm with no underfloor insulation which are are the main living areas & 2 of the bedrooms).

In addition, I've recently identified that parts of the house don't have wall insulation, and the ceiling insulation is a bit "Iffy" in parts (Some Gaps and I've just replaced Halogen down lights with Leds)

So i'm after a few bits of advice:

Is the quoted $1,623 reasonable for ~42sqm of R1.5 insulation and a moisture barrier
Are there any solutions out there for low clearance underfloor insulation (Google hasn't been helping)
Would you priorities additional ceiling and then retrofit wall insulation before underfloor?

Note: I also asked about ducted Heat pump (House came with 2 un-flued plumbed Gas heaters which have been placed with electric) but was advised that supply is an issue and they are not doing Ducted heat-pumps at the moment.

Appreciate any help and advice.

1 | 2

20591 posts

Uber Geek

Trusted

Lifetime subscriber

#2920643 30-May-2022 21:30

That's more expensive than when I had mine done in 2007, but maybe consider whether you'd want to do it yourself and how long it'd take, plus cost of materials. It's pretty horrible under many houses. Someone else might have more recent experience. The vapor barrier made a big difference at my place, we could get to about 80% of the underfloor.

I couldn't find any solution for low ground clearance other than to dig it out, but that can obviously cause problems. Interested in what others say here.

I would absolutely do ceiling insulation first. I would probably do double ceiling insulation before I did wall or underfloor, based on my experience with my weatherboard house which is probably similar age to yours. Ceiling makes the biggest difference by far. Wall and underfloor help, but not like ceiling insulation does. Any gaps in the insulation are a big problem, make sure there's no gaps at all.

I wrote a thread about ducted heat pumps here.

k1w1k1d

1528 posts

Uber Geek

#2920651 30-May-2022 22:16

We had R1.8 Mammoth underfloor insulation and moisture barrier done in February. Cost $1870 for 115m2.

vexxxboy

4245 posts

Uber Geek

#2920652 30-May-2022 22:28

have you looked into the Govt schemes where they will pay for insulation for a house that is that old , i got nearly $5,000 of insulation for my 1960's house and i paid 10% of that. Look up Warmer Kiwi Homes scheme and see if you qualify. Well worth it.

Common sense is not as common as you think.

jonherries

1396 posts

Uber Geek

Trusted

Subscriber

#2920653 30-May-2022 22:31

We had similar crawl space in our 1920s bungalow.

If you aren’t claustrophobic you can can carefully remove loose soil to make space, as often the waste from digging piles got spread out under the floor. We removed a lot (4-5 skip bins), then insulated and put down a moisture barrier, it made a massive difference for us (smell of house and humidity/dampness).

Jon

Bung

6498 posts

Uber Geek

Subscriber

#2920661 30-May-2022 23:16

Klysznz: Part of the house was too low to be insulated (29cm between ground & bearer)

Have you been under the house yourself?

roderickh

214 posts

Master Geek

#2920735 31-May-2022 09:11

We did a DPM exercise ourselves last year for a 130sqm home - DPM was about $150 and with tape etc totalled up to around $200 or so.

We then also purchased overalls and knee pads which added to the cost.

It was an absolute PITA, happy we did it but definitely wouldn't do again... (I am 1.8m tall and not the smallest guy)

On a side note, have you considered raising the insulation to meet the proposed new standards?

Sharesies referral

Klysznz

8 posts

Wannabe Geek

#2920847 31-May-2022 12:33

k1w1k1d:

We had R1.8 Mammoth underfloor insulation and moisture barrier done in February. Cost $1870 for 115m2.

Are you in Auckland and could you share the name of the company you used?

Quic Broadband

Move to New Zealand's best fibre broadband service (affiliate link). Free setup code: R587125ERQ6VE. Note that to use Quic Broadband you must be comfortable with configuring your own router.

testycanuck

5 posts

Wannabe Geek

ID Verified

#2920875 31-May-2022 13:31

Recently got Greenstuf R1.8 installed, 101m2 for 1,919 in Auckland region by Elite Insulation. Already had a moisture barrier so not sure how much more that would cost

elpenguino

3427 posts

Uber Geek

#2920883 31-May-2022 13:59

timmmay:

That's more expensive than when I had mine done in 2007, but maybe consider whether you'd want to do it yourself and how long it'd take, plus cost of materials. It's pretty horrible under many houses. Someone else might have more recent experience. The vapor barrier made a big difference at my place, we could get to about 80% of the underfloor.

I couldn't find any solution for low ground clearance other than to dig it out, but that can obviously cause problems. Interested in what others say here.

I would absolutely do ceiling insulation first. I would probably do double ceiling insulation before I did wall or underfloor, based on my experience with my weatherboard house which is probably similar age to yours. Ceiling makes the biggest difference by far. Wall and underfloor help, but not like ceiling insulation does. Any gaps in the insulation are a big problem, make sure there's no gaps at all.

I wrote a thread about ducted heat pumps here.

I agree with most of your post except about the (non) effectiveness of wall insulation.

Imagine going outside on a cold day wearing 3 jumpers and no pants.

There's absolutely a benefit to wall insulation, in summer and winter.

Most of the posters in this thread are just like chimpanzees on MDMA, full of feelings of bonhomie, joy, and optimism. Fred99 8/4/21

timmmay

20591 posts

Uber Geek

Trusted

Lifetime subscriber

#2920964 31-May-2022 14:36

elpenguino:

I agree with most of your post except about the (non) effectiveness of wall insulation. Imagine going outside on a cold day wearing 3 jumpers and no pants. There's absolutely a benefit to wall insulation, in summer and winter.

I am just saying that after we did wall insulation we didn't really notice much difference in temperature or heating costs, whereas when adding extra ceiling insulation or a vapor barrier the difference was quite obvious. All types of insulation should help, and I'm sure they do at least a bit, but some houses will get more benefit than others. I've seen someone on GZ say it made a huge difference for them.

Shrapz

126 posts

Master Geek

ID Verified

#2920981 31-May-2022 15:04

We just got our quote for ceiling, underfloor and vapour barrier. Note our install is very easy as we have a large space underhouse where you can walk.

Something to compare to

JayADee

2148 posts

Uber Geek

#2921044 31-May-2022 17:24

It would have cost us a touch over $2700 for 140m2 of Temper Cloud Poly Ceiling Blkt R2.9 last year except the government scheme ended up paying for it. Felt like a miracle. Not often you get something that useful for 'nothing' (being mindful we all pay taxes and that's where it came from plus some local trust money)

Definitely check to see if you are eligible for the government funding.
https://tools.eeca.govt.nz/warmer-kiwi-homes-tool

We got the above poly blanket as a top up for the existing pink bat ceiling insulation which was less than great in places, particularly over the lounge and the r value wasn't up to the latest standard. It wasn't terrible to start with (we put some of it it in a few decades ago to add to what was there when we moved in) but I was unprepared for what a big difference the top up made. It also didn't hurt that we bought some curtains for French doors we didn't use to have curtains for. I also went around and added more weather stripping to gaps. It all adds up.

For sure get the ceiling done to the best standard you can, it makes a huge difference.

We had most of the underfloor done around 2012 or thereabouts and the plastic on the ground too. There's a section that's hard to get at under the fourth bedroom that I reckon another company would have done (once you're in there it isn't particularly low but it's awkward, you'd have to do a lot of squirming.) I'm still debating trying to get it done by another company. Anyway, I found the underfloor also made a big difference. We have tongue and groove wooden floors with no carpet. You really notice the heat retention like if you walk over where the dog was laying.

When we got the underfloor done they used white, spun (polyester?) between joists. Now they do a blanket/sheets that covers the whole of the underfloor I understand. I bet that works better.

Oh and why not get a couple quotes?

Firenyth

2 posts

Wannabe Geek

#2921334 1-Jun-2022 11:08

JayADee:

It would have cost us a touch over $2700 for 140m2 of Temper Cloud Poly Ceiling Blkt R2.9 last year except the government scheme ended up paying for it. Felt like a miracle. Not often you get something that useful for 'nothing' (being mindful we all pay taxes and that's where it came from plus some local trust money)

Definitely check to see if you are eligible for the government funding.
https://tools.eeca.govt.nz/warmer-kiwi-homes-tool

We got the above poly blanket as a top up for the existing pink bat ceiling insulation which was less than great in places, particularly over the lounge and the r value wasn't up to the latest standard. It wasn't terrible to start with (we put some of it it in a few decades ago to add to what was there when we moved in) but I was unprepared for what a big difference the top up made. It also didn't hurt that we bought some curtains for French doors we didn't use to have curtains for. I also went around and added more weather stripping to gaps. It all adds up.

For sure get the ceiling done to the best standard you can, it makes a huge difference.

We had most of the underfloor done around 2012 or thereabouts and the plastic on the ground too. There's a section that's hard to get at under the fourth bedroom that I reckon another company would have done (once you're in there it isn't particularly low but it's awkward, you'd have to do a lot of squirming.) I'm still debating trying to get it done by another company. Anyway, I found the underfloor also made a big difference. We have tongue and groove wooden floors with no carpet. You really notice the heat retention like if you walk over where the dog was laying.

When we got the underfloor done they used white, spun (polyester?) between joists. Now they do a blanket/sheets that covers the whole of the underfloor I understand. I bet that works better.

Oh and why not get a couple quotes?

This here, we discovered we were missing some ceiling insulation in our home, so we got a few inspections to come check insulation for this grant. we are getting a poly blanket put in our roof and the floor insulation touched up, for free, thanks to the government 80% discount and some 3rd party grants/discounts.
definitely want to call around and get multiple inspectors to come have a look, some wanted us to pay, some barely had a look and one had a actual proper look and gave us the free insulation job.

MikeAqua

7785 posts

Uber Geek

#2921392 1-Jun-2022 12:57

We haven't done any for a few years. However we've always used wool and found the wool underfloor (which has synthetic layer at the bottom) to be excellent. R1.5 sounds a bit light to me.

I personally think that insulation is an all or nothing thing. while every bit helps, full insulation just seems to work that bit betterer.

It's a pity someone hasn't developed a spray on foam system for low clearance floors. I've seen spray on insulation used in marine environments and it works. I'm imagining a little remote control rover with a camera and spray gun.

When I insulated my first house, I managed to deal with 25cm between framing and floor in the worst places. It was a hideous ordeal. I put the plastic down first, under the whole floor in autumn then waited until late summer so the timber all dried out. Then I put the insulation in. I mention this for three reasons.

First: The plastic itself made noticeable difference over winter to the apparent temperature inside the house.

Second: parts of the floor framing moved as they dried out. In the end I had to address framing height in a couple of places (actually not hard to do).

Third: once the plastic is down, It's much easier to move around. I was wearing once of those white coverall things, which was slightly plasticky and it made it easy to slide on the ground sheeting. Being able to move freely in the horizontal plane made being under a very low floor seem much less claustrophobic.

Mike

evilengineer

466 posts

Ultimate Geek

#2921400 1-Jun-2022 13:17

I'd agree that R1.5 is a bit light.

Go big or go home in my opinion, particularly if it's a DIY job.

I did my house which has a 400-500mm sub-floor space and its not an experience I'd want to repeat.

Most underfloor products do seem to be R1.5 or R1.8 at present but this will have to change as the upcoming version of H1 says R2.5 for suspended timber floors in all climate zones.

1 | 2