Retrofit dry blown wall insulation - Anyone here with experience?

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Wheelbarrow01

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#218070 24-Jul-2017 15:21

Has anyone here had experience having retrofit dry blown insulation installed in their brick veneer house where no wall insulation already exists?

I'm currently considering having the Insulmax product installed in the walls of my 1960's brick veneer home. Keen to get feedback from anyone who has had a similar product installed with regards to the results.

Not interested in the wet stuff ie foam - have heard nothing but trouble about that stuff...

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#1828522 24-Jul-2017 16:11

I got the one that's a foam pumped into the wall cavity of my weatherboard house. It made very little difference to warmth, and I don't know about noise - probably a little. Also consider that if you fill the cavity there's no space for any water to evaporate or drain.

I wouldn't do it again.

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#1828608 24-Jul-2017 18:19

^ + 1

We looked at purchasing a house that had a brick veneer. The building inspector noticed something amiss in the ensuite and it turned out when it had been added, the lagging around the pipes in the wall was touching both the inner wall and the outer brick. Any condensation that had run down the inside of the wall had been wicked across by the laggin to the inner wall, which had begun to rot from the inside. When chatting to him about it, he said he had seen the same from retro-fit insulation that was in contact with the bricks and the inner wall - recommended staying well away from it.

mattwnz

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#1828610 24-Jul-2017 18:23

I would suggest getting a building consent for this type of work (even if it isn't needed), so the council can check that it complies with the building code, and sign it off. You certainly never want insulation installing between the brick and outer side of the framing, as that has to be left clear.

Fred99

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#1828648 24-Jul-2017 19:39

mattwnz:

I would suggest getting a building consent for this type of work (even if it isn't needed), so the council can check that it complies with the building code, and sign it off. You certainly never want insulation installing between the brick and outer side of the framing, as that has to be left clear.

Interesting...

Here's MBIE's determination on one case where consent for use of that specific system was refused.

Some time needed to read all of that, but a TL:DR version:

Was refused building consent.

MBIE determined that refusal was warranted - as there wasn't enough information provided.

MBIE then determined - on receiving more information - that consent should be granted.

In that case the house was older than the OP's - but probably similar - many '60s brick veneer houses won't have building paper.

They (MBIE) seem to accept that with this material, bridging of the cavity may be okay.

In that case the brick was rendered and painted - which was a positive.

There are coatings that can be applied over brick to reduce water absorption. I think you'd need to apply for consent to see if they decide this is needed.

Consent exemption (Schedule 1) might be possible. I think you'd need to talk to council again on this.

mdf

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#1828651 24-Jul-2017 19:54

Installing any insulation to exterior walls requires a building consent (see exemption 13 / page 44).

The (super interesting) case @Fred99 linked to shows that building consent _can_ be obtained, but there is a bit of work required to show the council that it is appropriate. Most brick veneer houses rely on the cavity behind the bricks for draining any moisture. In that case, they were able to show that there wasn't any moisture gaining entry so it was okay. I've seen a brick wall where you could see daylight through the mortar so that won't always be the case. Many will not even have building paper or a wrap.

In terms of insulation, I've looked in to the expanding foam option previously and rejected it on the basis of performance and moisture (I appreciate you're talking about a different product here). Ended up pulling out the gib and just putting normal bats in. Very happy with that decision.

mattwnz

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#1828656 24-Jul-2017 20:05

Fred99:
mattwnz:

I would suggest getting a building consent for this type of work (even if it isn't needed), so the council can check that it complies with the building code, and sign it off. You certainly never want insulation installing between the brick and outer side of the framing, as that has to be left clear.

Interesting...

Here's MBIE's determination on one case where consent for use of that specific system was refused.

Some time needed to read all of that, but a TL:DR version:

Was refused building consent.

MBIE determined that refusal was warranted - as there wasn't enough information provided.

MBIE then determined - on receiving more information - that consent should be granted.

In that case the house was older than the OP's - but probably similar - many '60s brick veneer houses won't have building paper.

They (MBIE) seem to accept that with this material, bridging of the cavity may be okay.

In that case the brick was rendered and painted - which was a positive.

There are coatings that can be applied over brick to reduce water absorption. I think you'd need to apply for consent to see if they decide this is needed.

Consent exemption (Schedule 1) might be possible. I think you'd need to talk to council again on this.

I am guessing that the paint and plaster layer is supposed to stop any water fransferring through the bricks, as normally bricks and mortar are porous? But with normal brick veneer houses, the cavity is there for a reason. Also generally you want the insulation on the inside of the wrap, not on the outer side.

If it was me I would be applying for consent anyway. Also helps when selling so the buyer can see that the work has all been signed off.

Fred99

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#1828659 24-Jul-2017 20:16

mattwnz:
Fred99:

mattwnz:

I would suggest getting a building consent for this type of work (even if it isn't needed), so the council can check that it complies with the building code, and sign it off. You certainly never want insulation installing between the brick and outer side of the framing, as that has to be left clear.

Interesting...

Here's MBIE's determination on one case where consent for use of that specific system was refused.

Some time needed to read all of that, but a TL:DR version:

Was refused building consent.

MBIE determined that refusal was warranted - as there wasn't enough information provided.

MBIE then determined - on receiving more information - that consent should be granted.

In that case the house was older than the OP's - but probably similar - many '60s brick veneer houses won't have building paper.

They (MBIE) seem to accept that with this material, bridging of the cavity may be okay.

In that case the brick was rendered and painted - which was a positive.

There are coatings that can be applied over brick to reduce water absorption. I think you'd need to apply for consent to see if they decide this is needed.

Consent exemption (Schedule 1) might be possible. I think you'd need to talk to council again on this.

I am guessing that the paint and plaster layer is supposed to stop any water fransferring through the bricks, as normally bricks and mortar are porous? But with normal brick veneer houses, the cavity is there for a reason. Also generally you want the insulation on the inside of the wrap, not on the outer side.

If it was me I would be applying for consent anyway. Also helps when selling so the buyer can see that the work has all been signed off.

There's discussion in the document I linked to there about that - also the impact on ventilation to sub-floor and ceiling cavity etc once the wall cavity is blocked off.

Yes - I'd be applying for consent - not assuming Schedule 1 exemption.

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nickb800

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#1828661 24-Jul-2017 20:23

For many reasons, I wouldn't touch it with a barge pole.

- It may spook future purchasers if found in a building report

- The MBIE-council-agent *hitstorm linked to above

- The risk of mould and timber decay if any part of your 50 year old cladding, roofing or flashings starts to let water in

- The risk that the insulation will perform less than expected due to moisture ingress

- It breaches the basic principle of a drained, ventilated cavity which the designers and builders of your house relied on and assumed would remain

I'm probably being a bit conservative here, and yes the alternative of removing interior linings to insulate is a huge job (in terms of time, money and hassle), but I just don't think these sorts of products are worth the risk

Wheelbarrow01

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#1828750 24-Jul-2017 22:49

So the stuff I am considering is installed under the Insulmax brand - www.insulmax.co.nz . I have read the technical specifications on their website, and I understand it to have the following attributes:

Thermal Performance: R2.8 @100mm thickness (for direct fixed cladding ie timber cladding), R4.2 @ 150mm (for typical masonry veneer cladding)

Water Resistant: Treated with inert water repellant, non hydroscopic - floats on water, will not wick or absorb water. They left me a sample when they visited to do the quote. It's been floating on the surface of a glass of water on my bench for a week. It really will not absorb water at all.

Installed under (low) pressure so will not settle (less than 1%)

Will not react with TPS in-wall cabling.

Negligible resistance to water vapour movement - it's breathable but will not wick. I found this video quite interesting

Non combustible to A1 standard.

Installed in over 6 million European homes.

50 Year written guarantee.

Compliance

The Insulmax® Retrofit Wall Insulation Method holds CodeMark certification for installation in all types of existing buildings in New Zealand. Compliance of this product with the requirements of clauses B1, B2, F2, E2, C3 and H1 of the N.Z Building Code is monitored by the CodeMark cerfication body AssureQuality.

Building consent

All forms of external retro wall insulation require an application for building consent, unless a written exemption has been issued by your local council. After assessing the property, only a trained and licensed Insulmax® representative is able to prepare the building consent application on the owners behalf.

Scope of use

The CodeMark certificate covers the retrofitting of Insulmax® wall insulation in all existing buildings. The product can be used in all types of exterior wall structure, with or without building paper. This includes but is not limited to: timber claddings, masonry veneer, brick veneer, solid/rendered plaster, Fibro, EIFS and double brick construction.

In my case, my exterior brick is already painted with an elastomeric paint - it's waterproof. Upon completion of the installation I'll be painting over the filled holes with the same elastomeric paint to preserve the current weather tightness of my brick cladding. After the installation is complete, they use thermal imaging to ensure no spots have been missed. They brought the thermal camera to the quoting session. I was pleased to see that the insulation I installed in my skillion ceiling a year ago is still perfectly in place with no gaps.

There are plenty of testimonials listed on their website, but of course I am interested in hearing from anyone else who has had it done to see what their experience has been.

mattwnz

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#1828759 25-Jul-2017 00:04

I think there is a bit of confusion here. Are they wanting to install it in the actual framing cavity (where normally insulation should go). Or are they wanting to install in the cavity between the back of the brick, and the front of the framing, which is infront of the building wrap? The retrofit systems I have seem always go in the actual framing, which will also provide a far thicker insulation layer. Usually the problem with systems that are loose, is they can compact down over time, leaving uninsulated patches at the top. You can get the same problem with normal wool insulation too.

nickb800

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#1828774 25-Jul-2017 07:11

mattwnz:

I think there is a bit of confusion here. Are they wanting to install it in the actual framing cavity (where normally insulation should go). Or are they wanting to install in the cavity between the back of the brick, and the front of the framing, which is infront of the building wrap? The retrofit systems I have seem always go in the actual framing, which will also provide a far thicker insulation layer. Usually the problem with systems that are loose, is they can compact down over time, leaving uninsulated patches at the top. You can get the same problem with normal wool insulation too.

It goes in both the framing cavity and the brick cavity - they are effectively one cavity as there is no building paper or wrap in houses of this type from this era

Wheelbarrow01

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#1828787 25-Jul-2017 08:03

mattwnz:

I think there is a bit of confusion here. Are they wanting to install it in the actual framing cavity (where normally insulation should go). Or are they wanting to install in the cavity between the back of the brick, and the front of the framing, which is infront of the building wrap? The retrofit systems I have seem always go in the actual framing, which will also provide a far thicker insulation layer. Usually the problem with systems that are loose, is they can compact down over time, leaving uninsulated patches at the top. You can get the same problem with normal wool insulation too.

This particular company fills the entire void - so both where normal batt insulation goes, as well as the space between the framing and brick cladding. This is what allows them to gain such a high R value - R4 or above depending on the cavity depth. They can do this in older homes that have no building wrap (such as mine). This particular system is installed under pressure so it actually ends up quite compacted - to the point that if you ever have to remove the Gib board, the insulation will for the most part stay in place.

Although tightly packed, they state the product is breathable and will not wick or absorb water and the sample they left at my house which I have been playing around with does tend to back this up.

Wheelbarrow01

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#1828792 25-Jul-2017 08:07

timmmay:

I got the one that's a foam pumped into the wall cavity of my weatherboard house. It made very little difference to warmth, and I don't know about noise - probably a little. Also consider that if you fill the cavity there's no space for any water to evaporate or drain.

I wouldn't do it again.

Yea I've heard nothing but bad reports about retrofit foam. For a start it goes in wet which makes it damp from the start and then there is the shrinkage issue which creates many gaps over time and has been well documented. I believe most councils won't even give a building consent for it anymore.

I guess the benefit of what I am looking at is that it is a dry product, installed under pressure which (they claim) means it will not settle.

Wheelbarrow01

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#1828797 25-Jul-2017 08:27

Fred99:

mattwnz:

I would suggest getting a building consent for this type of work (even if it isn't needed), so the council can check that it complies with the building code, and sign it off. You certainly never want insulation installing between the brick and outer side of the framing, as that has to be left clear.

Interesting...

Here's MBIE's determination on one case where consent for use of that specific system was refused.

Some time needed to read all of that, but a TL:DR version:

Was refused building consent.

MBIE determined that refusal was warranted - as there wasn't enough information provided.

MBIE then determined - on receiving more information - that consent should be granted.

In that case the house was older than the OP's - but probably similar - many '60s brick veneer houses won't have building paper.

They (MBIE) seem to accept that with this material, bridging of the cavity may be okay.

In that case the brick was rendered and painted - which was a positive.

There are coatings that can be applied over brick to reduce water absorption. I think you'd need to apply for consent to see if they decide this is needed.

Consent exemption (Schedule 1) might be possible. I think you'd need to talk to council again on this.

Thanks for this, I found it very interesting - especially given it involves the company I have engaged to provide my quote (Insulmax). In that example the house is older than mine, but still very similar by the sound of it. My house does not have building paper, and my brick cladding has already been painted with an elastomeric paint. This has been used widely in Canterbury after the quakes to provide an additional layer of weatherproofing to brick and block cladding where EQ cracks have been repaired or remortared. Elastomeric paint has a rubberising effect - it essentially provides a waterproof membrane which ensures no water ingress at the mortar joints (or through the bricks themselves).

Insulmax retrofit insulation does require a building consent and this is included in the quote I have.

mdf

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#1828820 25-Jul-2017 09:38

I have to say, I was pretty skeptical about any kind of blown insulation but it sounds like the insulmax stuff might stack up. It's been approved by the building consent guy (the case linked to by Fred), as well as holding various certifications and the fact they include the building consent stuff (hopefully) shows they're not cowboys. You've actually got an advantage with no building paper, as you have one big cavity that should fill up with a complete barrier, with no thermal breaks due to studs and dwangs.

I was concocting an experiment in my head. If you've got the time/inclination and a bit of the stuff, I thought this might be interesting (but I am not a licensed building practitioner - own risk etc.)

Suppose you wrap 5 sides of a dry block of the insulation with paper/cardboard/something that will change colour when wet - four sides plus the bottom. Dribble a bit of water on the open top. Something like an eye dropper would be ideal. If the sides of the block get wet, that could be a problem, as it shows that the water is not draining down. If the bottom doesn't get wet, again, that could be a problem because the moisture will be being retained by the insulation.

You might like to also do a control, to see how long it takes a piece of uncovered paper to dry from wet vs a piece of paper with the insulation sitting on top of it (i.e. how breathable is it?).

EDIT: sorry, actually watched the video you linked to above. Seems to satisfy my thought experiment that water will drain down, not sit there/go sideways.

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