Spray Foam Insulation

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AACTech

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#1200489 19-Dec-2014 11:38

gazbo: Spray type foam will shrink away from the framing during setting which leaves uninsulated gaps at framing lines that leak heat to the exterior.

Depending on your finish to the internal linings and the type of external cladding you have, you will get better performance by removing either of these two linings and install a standard fitted product such as batts. This is more expensive now but will be paid back in power savings over time.

From what I can gather "closed cell polyurethane foam insulation" has not really been used extensively in New Zealand and when it has been used it has been in commercial buildings. In Europe and North America it is used extensively in residential buildings. The Canadian contractor, Mike Holmes, with the TV show swears by it.

I think what most people in this forum have been mainly talking about is a UFFI or urea-formaldehyde foam insulation, which incidentally was banned in Canada 33 years ago because of the formaldehyde. It is a very different product.

"Properly applied (polyurethane) spray foam will not sag, settle or shrink. Shrinkage of spray foam insulation occurs within 24 hours of spraying and curing. When the cured foam shows signs of pulling away from the substrate, the most common cause is surface temperature. Another reason could be improperly mixing chemicals. The A and B need to mix at a 1-1 ratio for proper foam to be made. The main way to prevent improper spray foam insulation application is to do a couple of test patches. While the foam is curing, look for signs of it pulling away from the substrate, the density and uniformity of the cells, the colour and the texture. “A” rich foam is crunchy and glassy while “B” rich foam is soft and squishy. If any of these characteristics are not correct, examine the substrate for moisture and excess heat or cold."

Batts shrink and sag, moisture and air pass through it where as closed cell polyurethane foam does not.

The foam also has a much higher insulation rating. Getting close to double that of fibreglass.

mdooher

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#1200525 19-Dec-2014 12:27

AACTech:
gazbo: Spray type foam will shrink away from the framing during setting which leaves uninsulated gaps at framing lines that leak heat to the exterior.

Depending on your finish to the internal linings and the type of external cladding you have, you will get better performance by removing either of these two linings and install a standard fitted product such as batts. This is more expensive now but will be paid back in power savings over time.

From what I can gather "closed cell polyurethane foam insulation" has not really been used extensively in New Zealand and when it has been used it has been in commercial buildings. In Europe and North America it is used extensively in residential buildings. The Canadian contractor, Mike Holmes, with the TV show swears by it.

I think what most people in this forum have been mainly talking about is a UFFI or urea-formaldehyde foam insulation, which incidentally was banned in Canada 33 years ago because of the formaldehyde. It is a very different product.

"Properly applied (polyurethane) spray foam will not sag, settle or shrink. Shrinkage of spray foam insulation occurs within 24 hours of spraying and curing. When the cured foam shows signs of pulling away from the substrate, the most common cause is surface temperature. Another reason could be improperly mixing chemicals. The A and B need to mix at a 1-1 ratio for proper foam to be made. The main way to prevent improper spray foam insulation application is to do a couple of test patches. While the foam is curing, look for signs of it pulling away from the substrate, the density and uniformity of the cells, the colour and the texture. “A” rich foam is crunchy and glassy while “B” rich foam is soft and squishy. If any of these characteristics are not correct, examine the substrate for moisture and excess heat or cold."

Batts shrink and sag, moisture and air pass through it where as closed cell polyurethane foam does not.

The foam also has a much higher insulation rating. Getting close to double that of fibreglass.

that stuff that Mike Holmes uses is amazing, what's more amazing is how easy it looks to do...and how clearly it is anything but easy... As for the stuff they retrofit into non insulated walls here ... yeah; Nah

Matthew

gazbo

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#1200629 19-Dec-2014 15:45

From what I can gather "closed cell polyurethane foam insulation" has not really been used extensively in New Zealand and when it has been used it has been in commercial buildings. In Europe and North America it is used extensively in residential buildings. The Canadian contractor, Mike Holmes, with the TV show swears by it.

Batts shrink and sag, moisture and air pass through it where as closed cell polyurethane foam does not.

The foam also has a much higher insulation rating. Getting close to double that of fibreglass.

Canadian construction is a bit different in that walls are fully sheathed and vapour barriers such as polyethylene are installed which prevent any moisture from passing through. This is standard with their construction which relies on a rainscreen usually in the form of a cavity behind the cladding which allows drainage of any moisture which penetrates the exterior cladding.

In New Zealand rainscreens or similar were more or less compulsory for new houses that scored greater than 6 on the E2/AS1 3rd Edition risk matrix introduced in 2004 and implemented in January of 2005. However, we still do not allow a vapour barrier that prevents diffusion to be installed over framing as this stops any moisture that is sourced internally or penetrates externally from exiting the building quickly. Diffusion is a slow process that takes months but one off leaks will dry out eventually - except if a vapour barrier is installed. This will force water to migrate inwards rather than outwards.

I suspect that existing houses in New Zealand with wood framing and direct fixed cladding would suffer several problems after installing a closed cell foam insulation that is fully adhered to framing. The insulation will act as a vapour barrier preventing drying by diffusion of any moisture source and possibly interstitial condensation of internal moisture will occur on the surface of the insulation damaging internal linings and/or adjacent framing (particularly if the framing is untreated or poorly treated as allowed between 1996 - 2004).

I also note that it is not possible to inspect gaps in the insulation after setting if injecting through existing linings. The only way to ensure proper installation and plug any gaps that occur due to shrinkage during setting is to remove all the linings which defeats the purpose of using an injected material.

Lastly properly installed batts will not sag. I have pulled apart many failed buildings over the last 10 years and have seen the best and worst and properly installed batts work just fine. At least with batts you can see exactly how they are installed prior to lining. With in-situ injection you are completely reliant on the installer and even they will have no idea if they have missed any wall areas due to randomly installed blocking of nogs/dwangs.

Fred99

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#1200636 19-Dec-2014 16:00

There is information relevant to NZ on the MBIE / DBH website.
Building consent is required for this, except in Christchurch at the moment (so that someone could re-clad and or re-line EQ damaged home "like for like" and insulate external walls very cheaply and easily at the same time)

AACTech

34 posts

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#1200657 19-Dec-2014 16:41

gazbo:
From what I can gather "closed cell polyurethane foam insulation" has not really been used extensively in New Zealand and when it has been used it has been in commercial buildings. In Europe and North America it is used extensively in residential buildings. The Canadian contractor, Mike Holmes, with the TV show swears by it.

Batts shrink and sag, moisture and air pass through it where as closed cell polyurethane foam does not.

The foam also has a much higher insulation rating. Getting close to double that of fibreglass.

Canadian construction is a bit different in that walls are fully sheathed and vapour barriers such as polyethylene are installed which prevent any moisture from passing through. This is standard with their construction which relies on a rainscreen usually in the form of a cavity behind the cladding which allows drainage of any moisture which penetrates the exterior cladding.

In New Zealand rainscreens or similar were more or less compulsory for new houses that scored greater than 6 on the E2/AS1 3rd Edition risk matrix introduced in 2004 and implemented in January of 2005. However, we still do not allow a vapour barrier that prevents diffusion to be installed over framing as this stops any moisture that is sourced internally or penetrates externally from exiting the building quickly. Diffusion is a slow process that takes months but one off leaks will dry out eventually - except if a vapour barrier is installed. This will force water to migrate inwards rather than outwards.

I suspect that existing houses in New Zealand with wood framing and direct fixed cladding would suffer several problems after installing a closed cell foam insulation that is fully adhered to framing. The insulation will act as a vapour barrier preventing drying by diffusion of any moisture source and possibly interstitial condensation of internal moisture will occur on the surface of the insulation damaging internal linings and/or adjacent framing (particularly if the framing is untreated or poorly treated as allowed between 1996 - 2004).

I also note that it is not possible to inspect gaps in the insulation after setting if injecting through existing linings. The only way to ensure proper installation and plug any gaps that occur due to shrinkage during setting is to remove all the linings which defeats the purpose of using an injected material.

Lastly properly installed batts will not sag. I have pulled apart many failed buildings over the last 10 years and have seen the best and worst and properly installed batts work just fine. At least with batts you can see exactly how they are installed prior to lining. With in-situ injection you are completely reliant on the installer and even they will have no idea if they have missed any wall areas due to randomly installed blocking of nogs/dwangs.

I'm a computer geek not a builder so I'm no expert. As understand it in order for condensation to occur there must be warm air meeting a cold surface. So where is the cold surface and where is this moisture coming from? And so why aren't Canadian having moiusture problems?

All the NZ technical stuff on vapour barriers I've read seems to indicate that there is still a lot of confusion and that the jury is still out.
Very little real research has been done.

The purpose of foam is that it completely stops air and moisture and thus heat loss.

Many years ago, south of Nelson, I helped a chippy build a little batch (like a "batchelor" apartment in Canada) in the mountains. It was fully insulated on all 6 surfaces with fibreglass and with a vapour barrier. There was never a condensation problem and it was always warm and dry even the wet rainy mountain days. It didn't actually need any heating at all. Fixing your cuppa on the stove in the morning took the chill off the room - from stove not the tea.

Ever since that I have wanted to have a house in NZ like that.

timbosan

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#1200667 19-Dec-2014 16:58

I'm a computer geek not a builder so I'm no expert. As understand it in order for condensation to occur there must be warm air meeting a cold surface. So where is the cold surface and where is this moisture coming from? And so why aren't Canadian having moiusture problems?

I think (and I am prepared to be corrected on this), but the word you are missing is MOIST, as in " there must be MOIST warm air ", because if there is no moisture in the air, then = no condensation. And in reference to Canada, isn't is due to their very low humidity? When I was there in Jan (Calgary) I found the air so dry, I think it was < 30%, and I needed constant lip balm!

jonathan18

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#1231521 5-Feb-2015 09:32

I saw an article this morning on a new company building modular housing (from the old GM plant in Upper Hutt), and checked out their website (also mentioned in another thread on mortgages) - interestingly this states that:

Matrix homes use superior closed cell fire resistant polyurethane foam insulation for under-floor, wall and ceilings.

This not only provides a superior draught seal but also increases the strength of the walls and ceilings and excellent sound deadening.

The insulation complies to Climate 3 zone for all homes as standard.

Source: http://matrixhomes.co.nz/environment

(edit: formatting)

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Jase2985

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#1231525 5-Feb-2015 09:38

they need to sort out their hosting keep getting 508 errors

jonathan18

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#1231587 5-Feb-2015 10:37

Jase2985: they need to sort out their hosting keep getting 508 errors

Yeah, I did too for quite a while. What causes these errors? I'd imagine there'd be a bit of interest in the company, given the articles in the newspapers and on-line - and you'd think their website would be sorted prior to the official opening!

I was also surprised with the lack of photos of actual houses - CAD drawings (whether 2D or 3D) never replace images of the real thing.

timmmay

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#1231588 5-Feb-2015 10:45

508 - Resource limit is reached. Their website has gotten popular and has insufficient capacity to serve requests. They probably have cheaper hosting that isn't up to the publicity they've received.

Distorter

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#1231614 5-Feb-2015 11:22

Each time someone has updated this thread, I've checked the link and it's worked for me. Yet to see the problem :-D

MikeAqua

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#1234673 11-Feb-2015 13:09

That retrofit spray foam isn't great. Some of them emit formaldehyde, which is nasty.

The installer can't overfill the cavities or he will bulge the internal cladding, but if he under-fills, the insulation will be significantly less effective. It's a fine line, and voids, crack etc are almost unavoidable.

When we did our last place, we just ripped off the linings and fitted wool batts. The pink-batts between the framing in the ceiling stayed and we rolled a wool batting blanket over the top of the whole lot. Awesome. Amazing difference. The house even had a different ambience.

Mike

AACTech

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#1306287 16-May-2015 13:41

The only air without moisture would be in a lab.

Insulation with a vapour barrier solves the condensation problem. Everybody who know building insulation knows this. Unfortunately in New Zealand we have very little understanding of the basic princples.

It is very simple. If there is no vapour barrier the moisture passes through the interior wall into the insulated wall cavity. As it passes through the insulation material the temperature drops and the moisture precipitates into the insulation material.

It is just physics. Warm air holds more moisture than cold. "Warm" or "cool" is relative. All that is needed is a temperature differential. Look at a coke bottle in the summer.

You can especially see this in ceiling insulation where the bats actually shrink. Fortunately in attics the moisture is able to evaporate. In walls, well as you can see the evaporation process would be much impeded. So vapour barrier the entire house!

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