Insulation - good deals?

Forums › Home Workshop DIY › Insulation - good deals?

1 | 2 | 3 | 4

13684 posts

Uber Geek

#1101297 3-Aug-2014 20:52

We don't qualify for any subsidy. One of the reasons that I wanted to upgrade floor insulation was that we want to remove carpet from our living area, and polish floorboards. While it's nice to have close joist spacing, that joist spacing also compromises insulation because of extra thermal bridging. The sub-floor area was quite open and drafty - the house was clad in brick with ventilated cavity system. That's now been sealed off, a closed cavity system needed to meet code for the new cladding system. This also eliminated drafts around architraves etc. The sub-floor space is dry, and 1-3m above ground level. Two bedrooms are over - or partly over - a basement garage. After insulating - I may line the garage ceiling.
The floorboards themselves are T&G heart rimu, very tightly installed and flat - no drafts or gaps.

Stu

Hammered
8344 posts

Uber Geek

Moderator

ID Verified

Trusted

Lifetime subscriber

#1101306 3-Aug-2014 21:14

The part of our house that is only single level (where the bedrooms are) now has nice heavy duty polythene on the ground, and we'll be adding under-floor insulation in coming months. Brick cladding and currently no in wall insulation makes for a fair bit of work to remedy, and the old fluffy rubbish in the ceiling will have batts of some form added in time.

mattwnz

20164 posts

Uber Geek

#1101338 3-Aug-2014 22:32

BigHammer: DIY. Not our first reno, but the first time we've had to sort insulation as well. At this stage wool and polyester are the options we're looking at, but not finalized anything as yet. Cheers

If using wool for walls, I was recommended by an installer to staple it into the framing at sides and top, as wool can slump over time. The composite wool+polyester products however maybe better for this. If you are trying to compare the different insulation products, and the R values, this website is probably the best out there designnavigator.co.nz. It isn't pretty but it is a very useful tool.

gzt

17149 posts

Uber Geek

Lifetime subscriber

#1101341 3-Aug-2014 22:37

Fred99: The only (hopefully) easy to install sub-floor insulation I can find is Mammoth (recycled polyester).

Fred99:The floorboards themselves are T&G heart rimu, very tightly installed and flat - no drafts or gaps.

I have installed expol. There were enough variations in the joists to make that a real pita. Nearly every single bit had to measure precisely and select the right place to cut for a good fit. Time consuming. Sharp knife but still polystyrene bits everywhere and cut polystyrene smells surprisingly awful working in a confined space. In contrast I'm guessing a lot less trouble required with that mammoth product.

Edit: If I did it again tomorrow I would use the foil/polyester/foil blanket the commercial installers favor. Fast and clean.

Stu

Hammered
8344 posts

Uber Geek

Moderator

ID Verified

Trusted

Lifetime subscriber

#1101343 3-Aug-2014 22:42

mattwnz: If using wool for walls, I was recommended by an installer to staple it into the framing at sides and top, as wool can slump over time. The composite wool+polyester products however maybe better for this. If you are trying to compare the different insulation products, and the R values, this website is probably the best out there designnavigator.co.nz. It isn't pretty but it is a very useful tool.

Until we get the first sheet of gib off the walls, we don't know what we're dealing with. Won't start that stage until summer arrives. Just taking notes and getting prices for now. No hurry.

kiwitrc

4123 posts

Uber Geek
Inactive user

#1101375 4-Aug-2014 06:14

Fred99:
DarthKermit: Bump.

So how's your insulation project going?

We installed half of it last Sunday. The Knauf blanket lived up to the claims of being non-irritating, but of course there are already old pink batts in the roof space, which a truly horrible. Combine this with very limited roof space, dust, and the difficulty in either maneuvering long lengths of blanket into position, or cutting and butting it in some kind of methodical basis, and it would be fair to say that it wasn't a hell of a lot of fun. I have some alterations and EQ repairs to do at the other end of the house - so will wait until I've done that before rolling out the insulation in those areas. I hope that won't be quite so bad - access is a bit better.
Meanwhile, I had builders commence work this week, installing framing timber as "packing" for the new cladding system. For a few reasons, I've needed to work alongside the builders. They are working on rates - not a fixed-price quote. This could have caused some tricky issues, but has worked out perfectly. There are some damned good tradesmen out there. I'm more than happy to continue with the rest of the project to completion on rates - still too many tricky/unknown issues may arise. Weather permitting, we should be ready for pre-cladding council inspection this coming week.
Sub-floor insulation I haven't decided on yet. I'd like the highest R value possible. I should be in the basement now - ripping down the last of the old foil and dumping it in the 6m3 skip while it's here, but I need a day off.

What cladding system are you using ?

Fred99

13684 posts

Uber Geek

#1101424 4-Aug-2014 08:00

BigHammer:
mattwnz: If using wool for walls, I was recommended by an installer to staple it into the framing at sides and top, as wool can slump over time. The composite wool+polyester products however maybe better for this. If you are trying to compare the different insulation products, and the R values, this website is probably the best out there designnavigator.co.nz. It isn't pretty but it is a very useful tool.

Until we get the first sheet of gib off the walls, we don't know what we're dealing with. Won't start that stage until summer arrives. Just taking notes and getting prices for now. No hurry.

I'm not sure if you've factored this in, but fitting exterior wall insulation usually needs building consent. The "issue" is that if it's in contact with the brick veneer wall, or slumps and comes in contact with it, then it bridges and directs water to the framing, holds it there - so is a potential problem for rot. I believe that a solution is attaching building paper - working from the inside - and attaching to studs/dwangs.

Sharesies

Trade NZ and US shares and funds with Sharesies (affiliate link).

Fred99

13684 posts

Uber Geek

#1101430 4-Aug-2014 08:15

kiwitrc:

What cladding system are you using ?

A 75mm poly/plaster system designed to replace brick veneer (to work with deep cavity etc). In theory, it should have been easy. In practice - with the need to bring it up to code, there have been many issues.

Stu

Hammered
8344 posts

Uber Geek

Moderator

ID Verified

Trusted

Lifetime subscriber

#1101434 4-Aug-2014 08:22

Fred99: I'm not sure if you've factored this in, but fitting exterior wall insulation usually needs building consent. The "issue" is that if it's in contact with the brick veneer wall, or slumps and comes in contact with it, then it bridges and directs water to the framing, holds it there - so is a potential problem for rot. I believe that a solution is attaching building paper - working from the inside - and attaching to studs/dwangs.

Yes that's something we'll have to sort out once we find out what's there. Certainly an expense we don't need, but will jump that hurdle when we get to it. Cheers

gzt

17149 posts

Uber Geek

Lifetime subscriber

#1101890 4-Aug-2014 17:24

gzt:
Fred99: The only (hopefully) easy to install sub-floor insulation I can find is Mammoth (recycled polyester).

Fred99:The floorboards themselves are T&G heart rimu, very tightly installed and flat - no drafts or gaps.

I have installed edit: ~~expol~~ Bondor RetroTherm. There were enough variations in the joists to make that a real pita. Nearly every single bit had to measure precisely and select the right place to cut for a good fit. Time consuming. Sharp knife but still polystyrene bits everywhere and cut polystyrene smells surprisingly awful working in a confined space. In contrast I'm guessing a lot less trouble required with that mammoth product.

Edit: If I did it again tomorrow I would use the foil/polyester/foil blanket the commercial installers favor. Fast and clean.

Fwiw, the product I installed was Bondor RetroTherm =R1.4 (not Expol as I originally recalled above)

http://www.bondor.co.nz/brochures/974188001241558120.pdf

Several years ago now and I do not recall if I selected that (vs Expol) on price or specification or a bit of both.

Fred99

13684 posts

Uber Geek

#1105069 8-Aug-2014 18:33

Today I got pricing for "Mammoth" from two suppliers (Mitre 10 and Placemakers). I get a 10% loyalty card discount from Placemakers - so "retail" price was about the same.
There's a problem. The Mammoth "Multi" is extremely expensive. It's around $27 / m2 - so for 240m2, to do the sub-floor "material only" is almost $7000. All very nice with recycled PET and photos of cats, but they can forget about it at that price.
I can get Knauf subfloor panels for much less than 1/2 the price, it has a higher R rating, cutting it may result in wastage, and it may take me a little longer to install, but I'm not paying the price for the polyester insulation.
On a more positive note, I had council inspection for the complex proprietary flashing system and cavity batten system I've installed for our full home re-cladding. I knew we did a good job (builders and I) but it had been giving me nightmares, and I've spent many weeks planning, testing, then doing the work. We passed inspection. Bloody fantastic. The rest of the consent inspections are less of a concern to me - as I won't be so involved in technical aspects, and they're more routine.

Stu

Hammered
8344 posts

Uber Geek

Moderator

ID Verified

Trusted

Lifetime subscriber

#1105099 8-Aug-2014 19:52

Well done on passing the inspection. Should make sleeping a little more restful!

Thanks for the heads up on Mammoth. Won't even bother getting quotes on their products. It's going to be expensive enough without looking at gold plated products!

People often mistake me for an adult because of my age.

Keep calm, and carry on posting.

Referral Links: Sharesies - Backblaze -

Are you happy with what you get from Geekzone? If so, please consider supporting us by subscribing.

No matter where you go, there you are.

bfginger

1269 posts

Uber Geek

#1105136 8-Aug-2014 21:20

Are you sure that isn't retailer margin?

I can see someone selling Mammoth R3.6 polyester ceiling blankets for $16m2. Mammoth Multi is R1.9.

Greenstuf, Insulpro and Cocoon are the other brands of polyester.

Fred99

13684 posts

Uber Geek

#1105152 8-Aug-2014 21:55

bfginger: Are you sure that isn't retailer margin?

I can see someone selling Mammoth R3.6 polyester ceiling blankets for $16m2. Mammoth Multi is R1.9.

Greenstuf, Insulpro and Cocoon are the other brands of polyester.

I'm not sure if it's retailer margin and/or in the case of Placemakers, commercial bias in favour of Pink Batts. I mentioned the deal I got for Knauf Earthwool to the sales dude at Placemakers, and got a FUD lecture about foreign manufacturers, different R ratings. All BS - Fletcher is a mere peanut in the global market compared to Knauf.

DarthKermit

5346 posts

Uber Geek

Trusted

#1105171 8-Aug-2014 22:06

I used Knauf Earthwool for external wall insulation in our 2nd bedroom. Seems pretty good compared to no insulation which is what was there before.

Whatifthespacekeyhadneverbeeninvented?

1 | 2 | 3 | 4