External wall insulation - Insulmax or Cosywall

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apm45

63 posts

Master Geek

#300805 5-Oct-2022 19:35

Has anyone here had experience with either Insulmax or Cosywall insulation?

I've read the previous threads, and know Wheelbarrow01 had a very positive experience with Insulmax.

Both companies have Codemark certification and seem to use a similar product and methodology. I've had quotes from each, and I was more impressed with the Insulmax offering, but of course they're more expensive. So before I make a decision, I wondered if anyone here had dealt with Cosywall and what your experience was like. I know it may vary by region, depending on the installer, but I am still keen to hear any thoughts before I decide which to go with. Thanks.

tweake

2391 posts

Uber Geek

#2977957 5-Oct-2022 20:13

first thing to keep in mind that these products are so new that your not going to find anyone who has found problems. part of that is no one has had it a long time and no one is pulling apart walls to check. so your always going to get bias opinions.

frankly i would not recommend either.

thats due to their method of install is poking lots of holes through the weather barrier (how long before the repairs fail). poking holes trough any wrb (and not fixing them) if installed. it also can fill any space for drying which removes the walls ability to dry.

imho, pull off the gib, pocket install wrb, install insulation and any new power/data cables. re-gib and paint the room a new color. substantially better way to do it.

apm45

63 posts

Master Geek

#2977970 5-Oct-2022 21:04

Thanks for your input. Good point that flaws may not yet be apparent. I was hoping the Codemark gives some confidence, although obviously the leaky building crisis shows that Branz are far from perfect.

I really would rather not take off internal linings. The walls are in a reasonable condition, and I've already painted them. Also we have an old house with Rimu skirting and moulded architraves, so would need to cut the plasterboard above and below, and nervous about matching in.

I'm not worried about the holes in the weatherboards. About 20 mm diameter, and filled with epoxy and painted.

tweake

2391 posts

Uber Geek

#2977979 5-Oct-2022 21:19

i know branz pulled their cert for the products, not to sure how codemark differs. it says building code compliant but then again its not being used in buildings that are building code compliant.

the thing about the holes is if they leak. just like windows leak, which is fine when the walls are empty as it just dries. but fill it with insulation and then its difficult for it to dry. rot of course is simply how durable is the wood vers how long is the wood wet for.

have a look at https://youtu.be/0oDLwBZurp8

Arcturi

18 posts

Geek

#2982058 12-Oct-2022 18:14

I got Insulmax a couple of years ago in my 1960s brick veneer house. Unfortunately I did not think to track temperature and humidity data before and after, but subjectively it has made a difference in terms of warmth and comfort.

The local team did an average job of patching the holes they drilled in the mortar - most people would not notice but when you are looking closely, or know it's been done then the patching is visible.

Part of my reasoning for doing this rather than removing interior lining and making pockets in the framing:

Council consent process & cost (Invercargill) - Insulmax sorted the consent whereas if I was doing something myself I would have to pay a flat fee plus a cost per square metre for each room, and there would be 2 inspections at different stages. From memory it would be have been over $3k for consent to do the whole house, and if you want to do one room at a time then it ends up costing more because you have to pay the flat fee each time.
This way I didn't have to mess with removing skirtings & gib etc. so that was a huge saving in time and cost too
Ended up with higher R value as the cavity between studs and brick veneer was also filled

Obviously it hasn't been in long enough to know whether it will affect the wall's ability to dry. I had only double glazed part of the house at that point (more is getting done shortly!) and I think that will make more difference to heat retention than the Insulmax, so would prioritise double glazing and topping up ceiling insulation if not already done.

Cheers, Sarah

Arcturi

18 posts

Geek

#2982060 12-Oct-2022 18:17

Arcturi:

Council consent process & cost (Invercargill) - Insulmax sorted the consent whereas if I was doing something myself I would have to pay a flat fee plus a cost per square metre for each room

Clarification: the flat fee is per application, not per room! The cost per square metre is for each room you are insulating.

tweake

2391 posts

Uber Geek

#2982086 12-Oct-2022 19:26

Arcturi:

I got Insulmax a couple of years ago in my 1960s brick veneer house. Unfortunately I did not think to track temperature and humidity data before and after, but subjectively it has made a difference in terms of warmth and comfort.

The local team did an average job of patching the holes they drilled in the mortar - most people would not notice but when you are looking closely, or know it's been done then the patching is visible.

Part of my reasoning for doing this rather than removing interior lining and making pockets in the framing:

Council consent process & cost (Invercargill) - Insulmax sorted the consent whereas if I was doing something myself I would have to pay a flat fee plus a cost per square metre for each room, and there would be 2 inspections at different stages. From memory it would be have been over $3k for consent to do the whole house, and if you want to do one room at a time then it ends up costing more because you have to pay the flat fee each time.
This way I didn't have to mess with removing skirtings & gib etc. so that was a huge saving in time and cost too
Ended up with higher R value as the cavity between studs and brick veneer was also filled
Obviously it hasn't been in long enough to know whether it will affect the wall's ability to dry. I had only double glazed part of the house at that point (more is getting done shortly!) and I think that will make more difference to heat retention than the Insulmax, so would prioritise double glazing and topping up ceiling insulation if not already done.

Cheers, Sarah

the wall insulation will make substantially more difference than double glazing the windows. simply due to the larger area the wall is and the much higher increase in insulation value.

long term durability of the walls will be interesting to see. the simple issue is the cavity between the wall and brick is there to allow moisture (that comes through the brick) to go up and vent out. thats why its open top and has air vents at the bottom. fill that cavity, now where is the moisture going to go to?

joshtnx

19 posts

Geek

#3000367 23-Nov-2022 16:15

Hi OP did you end up going for this? I'm also interested, based in Wellington with a weatherboard timber home.

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

Groucho

524 posts

Ultimate Geek

#3000376 23-Nov-2022 16:38

tweake:

thats due to their method of install is poking lots of holes through the weather barrier (how long before the repairs fail). poking holes trough any wrb (and not fixing them) if installed. it also can fill any space for drying which removes the walls ability to dry.

I had a client (since retired) who did retro fit wall insulation. Had a bit of a chat and they only blew through the inside of the wall through the plasterboard and never from the outside. Don't remember if this was industry practice at the time or their own policy. He said you can fill and seal the holes in weatherboard but after a few years of expansion and contraction in the NZ sun gaps open up around the patch inviting moisture into the wall cavity.

apm45

63 posts

Master Geek

#3052569 20-Mar-2023 21:11

joshtnx: Hi OP did you end up going for this? I'm also interested, based in Wellington with a weatherboard timber home.

Late reply sorry, but we got it done in February. We went with Insulmax in the end. Although they were about 20% more expensive than Cosywall, they just seemed all around more professional - including that they apply for a consent exemption with the council. There was no mention of consent requirements at all from Cosywall.

Anyway, winter isn't here yet to really test the results, but straight away we noticed a significant noise reduction. Road noise and wind noise are much more muffled now, which is a great start. We also think it is a bit warmer in the rooms we had done - but until we get into the Dunedin winter we wont know how much.

The install was pretty efficient as well. Three walls of the house all done in about 5 hours, including drilling holes, installing the fluff, and then patching the holes with filler. They came back later to sand and paint the holes. That would be my one gripe - the painted patches are visible when looking from an angle. It would have been much better to have painted the full board rather than just around the holes. Also, the guy said the weather wasn't suitable to paint the second coat, so he just left the paint with us. I was a little disappointed with that.

dazzanz

214 posts

Master Geek

#3112987 7-Aug-2023 20:25

apm45:

Anyway, winter isn't here yet to really test the results, but straight away we noticed a significant noise reduction. Road noise and wind noise are much more muffled now, which is a great start. We also think it is a bit warmer in the rooms we had done - but until we get into the Dunedin winter we wont know how much.

Would you be able to provide another update now we are in to winter? Thanks

apm45

63 posts

Master Geek

#3114285 10-Aug-2023 17:32

I'm happy we got it done. It has made a noticeable difference over winter - less nights with a heater needed in the bedroom, and it definitely keeps the heat in longer.

It isn't night and day different, but enough that I would recommend it. It wasn't cheap, but when you consider the cost of removing either all the internal lining or external cladding, buying and installing insulation and then replacing and repainting, it feels like good value, and so little disruption to install it.

Was there anything else specific you wanted to know?

Wheelbarrow01

1725 posts

Uber Geek

Trusted

Chorus

#3114388 10-Aug-2023 23:38

apm45:

I'm happy we got it done. It has made a noticeable difference over winter - less nights with a heater needed in the bedroom, and it definitely keeps the heat in longer.

It isn't night and day different, but enough that I would recommend it. It wasn't cheap, but when you consider the cost of removing either all the internal lining or external cladding, buying and installing insulation and then replacing and repainting, it feels like good value, and so little disruption to install it.

Was there anything else specific you wanted to know?

I have previously posted at length about my experience with Insulmax on Geekzone so I won't repeat myself, but six years on from the installation I am still loving it. The difference it made to comfort in my house really was night and day. Sound intrusion from outside is very much reduced, and my house stays warm overnight with no heating whatsoever (which it certainly didn't do before).

Eg my lounge is 21 degrees right now with the fire almost completely out. Metservice says it feels like -2 outside right now, and I can predict with reasonable accuracy that at 8am tomorrow morning my house will still be around 16 degrees.

dazzanz

214 posts

Master Geek

#3114442 11-Aug-2023 10:21

Thanks for both updates. We are doing some renos and adding insulation through that but some rooms won’t be touched at all so considering going this route.