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Yvan Richard Posted: Jun 05, 2010 08:49 AM	flash & bat I have a number of potential clients that want 2" of 2lb foam and then want to put bat insulation. Being that the foam qualifies as a vapour barrier, however the foam/vapour barrier will not be on the warm side of the application. Will the bat insulation be effective on the warm side without a poly vapour barrier?
jimcoler I have over 10 years of experience specifying and installing open and closed cell spray foam. I've sold my business but I'm still selling for the new owners and consulting on large and custom specific jobs. I've expanded my knowledge into t Posted: Jun 05, 2010 10:44 AM	Anywhere North of Washington DC, I would say no to flash and batt!!! It's just wrong and we've already seen problems with customers who decided to go to competitors and have it done and call us 6 months to a year later and say they have water in their walls!!! In theory, it would be fine, but since filterglass is just that a filter of the air, it will still allow the moisture to pass through and condense on the inside of the foam/ inside edges of the studs! That brings up another point, that the studs are much more of a conductor of the heat than the foam. Since it's only an R-1 per inch of wood and we have 2" of wood separating the outside from the inside, it will condense on the studs before the foam. So, anywhere North of DC, I say no way!! Jim Coler
John Shockney Posted: Jun 05, 2010 11:02 AM	Check with Johns Manville on their recommendations they bought Corbond and have done testing for flash and bat systems. They do say that a closed cell only wall system is still better. I don’t personally recommend flash and bat because I don’t find any cost or performance advantage. I just was at a Walls That Work training in Indy put on by JM and Corbond they recommended no less that 1.5 inches of closed cell foam for a flash and bat system here in Indiana because of the possibility of condensation on the foam with less foam. I think they also did not require a vapor barrier but I could be wrong. Again check with a Johns Manville rep for their recommendations I have the Midwest rep’s email and phone # if you need it Hope this helps Airpro
Posted: Jun 06, 2010 06:41 AM	keep in mind,,, condensation will be happenin in the poorly insulated wall,,foam or not,,it will occur on the next available airspace,,in the flash n batt system this is the filterglass to foam interface... jimster,,i am wonderin,,these folks with water runnin out of the wall...im a guessin the flash n batt installer,,or the drywaller decided they didnt need a poly vapor retarder on the wall since the foam was there???? wrongly decided that is,,, computer modeling shows that 2" of cc foam is sufficient to provide enough thermal resistance to the xfer of hot to cold to prevent condensation on the foam face in my zone 5.. and if you anecdotally consider that foam "performs" at double its rvalue,,this 1.5" -2" app will indeed out perform its r19 filterglass competitor...but you will not have "great" increased performance,,,you cant put in half as much and expect twice a much,,, i consider the foam in a flash n batt system an air barrier system...stopping the uncontrolled air movement into and out of the studwall cavity,,it is not a thermal system adding only minimal r value to the whole wall... round here the filterglass folks who are just gettin in to foam are callin it a "skim coat"... and indeed that is what the customer gets,,1/2" or so in the wide open cavities,,,splatter/froth system works great then!!! and as sir jimster states,,then,,down the road you hear from the consumer who claims they dont see much difference in operating costs from their neighbors,,,go figure,, you cant have steak on a hamburger budget...
John Shockney Posted: Jun 06, 2010 01:06 PM	I have several competitors that do a ½ inch flash coat with fiberglass but most of my suppliers recommend a minimum of one inch per pass to get proper chemical reaction and yield, in fact I find not much more chemical is used to get that additional ½ inch in a one inch pass. Also if you put in 2 inches of foam what is the advantage of an R-13 bat you could add another inch of foam for about the same cost?? R-7 foam or R-13 fiberglass that really only R-5?? Airpro
jimcoler I have over 10 years of experience specifying and installing open and closed cell spray foam. I've sold my business but I'm still selling for the new owners and consulting on large and custom specific jobs. I've expanded my knowledge into t Posted: Jun 06, 2010 01:53 PM	The scenario that I was talking about was of a competitor who was using a specified thickness of 1" of closed cell but when you measure their jobs, you're lucky getting 1/2" in most cases. The thickness varied greatly between 1/2" and 1 1/2" but I still don't think that's enough! So, what does the Filtergalss do on the inside anyway? Is this just a ploy by the filterglass companies to try and keep in on the game? I think so!!! Let's look at the facts - Filterglass is down 40-60% in sales with the decline in the housing market. So they have manufacturing equipment sitting there idle for about 40-60% of the time. So, their marketing reps got together and asked, how do we keep the machines up to capacity? Their answer is to use the filterglass on the inside as a supplemental solution. But what we're finding is this isn't a solution, and it's actually hurting our industry because foam gets a bad name when moisture gets trapped in the walls. So when you follow the practicallity of the scenario, it makes sense! Just look at the rational behind it and it makes sense!
JohnPeters Posted: Jun 08, 2010 07:40 AM	ICC reg states that if your dealing with an air impermeable insulation medium (ie. SPF) a minimum of 3" should be applied to exterior sheathing (roof or wall). If your competitor is pushing flash and batt (ie. Masco) they are offering an application approach that is not compliant with current code. It is my understanding that this reg. is in code because of concerns regarding securing an air seal. On a more concerning note, anything less than 2" of CC will not provide a robust enough thermal break to stop hot from meeting cold (in climate zones 5-6). We all know what happens when hot meets cold. jp
Gerry Wagoner Posted: Jun 28, 2010 11:56 AM	I like the word "robust."

Author

Comments

Yvan Richard

Posted: Jun 05, 2010 08:49 AM

flash & bat

I have a number of potential clients that want 2" of 2lb foam and then want to put bat insulation. Being that the foam qualifies as a vapour barrier, however the foam/vapour barrier will not be on the warm side of the application. Will the bat insulation be effective on the warm side without a poly vapour barrier?

jimcoler

I have over 10 years of experience specifying and installing open and closed cell spray foam. I've sold my business but I'm still selling for the new owners and consulting on large and custom specific jobs.

I've expanded my knowledge into t

Posted: Jun 05, 2010 10:44 AM

Anywhere North of Washington DC, I would say no to flash and batt!!! It's just wrong and we've already seen problems with customers who decided to go to competitors and have it done and call us 6 months to a year later and say they have water in their walls!!! In theory, it would be fine, but since filterglass is just that a filter of the air, it will still allow the moisture to pass through and condense on the inside of the foam/ inside edges of the studs!

That brings up another point, that the studs are much more of a conductor of the heat than the foam. Since it's only an R-1 per inch of wood and we have 2" of wood separating the outside from the inside, it will condense on the studs before the foam.

So, anywhere North of DC, I say no way!!
Jim Coler

John Shockney

Posted: Jun 05, 2010 11:02 AM

Check with Johns Manville on their recommendations they bought Corbond and have done testing for flash and bat systems.

They do say that a closed cell only wall system is still better.

I don’t personally recommend flash and bat because I don’t find any cost or performance advantage.

I just was at a Walls That Work training in Indy put on by JM and Corbond they recommended no less that 1.5 inches of closed cell foam for a flash and bat system here in Indiana because of the possibility of condensation on the foam with less foam. I think they also did not require a vapor barrier but I could be wrong.

Again check with a Johns Manville rep for their recommendations I have the Midwest rep’s email and phone # if you need it

Hope this helps
Airpro

Posted: Jun 06, 2010 06:41 AM

keep in mind,,,
condensation will be happenin in the poorly insulated wall,,foam or not,,it will occur on the next available airspace,,in the flash n batt system this is the filterglass to foam interface...
jimster,,i am wonderin,,these folks with water runnin out of the wall...im a guessin the flash n batt installer,,or the drywaller decided they didnt need a poly vapor retarder on the wall since the foam was there???? wrongly decided that is,,,
computer modeling shows that 2" of cc foam is sufficient to provide enough thermal resistance to the xfer of hot to cold to prevent condensation on the foam face in my zone 5..
and if you anecdotally consider that foam "performs" at double its rvalue,,this 1.5" -2" app will indeed out perform its r19 filterglass competitor...but you will not have "great" increased performance,,,you cant put in half as much and expect twice a much,,,
i consider the foam in a flash n batt system an air barrier system...stopping the uncontrolled air movement into and out of the studwall cavity,,it is not a thermal system adding only minimal r value to the whole wall...
round here the filterglass folks who are just gettin in to foam are callin it a "skim coat"...
and indeed that is what the customer gets,,1/2" or so in the wide open cavities,,,splatter/froth system works great then!!!
and as sir jimster states,,then,,down the road you hear from the consumer who claims they dont see much difference in operating costs from their neighbors,,,go figure,,
you cant have steak on a hamburger budget...

John Shockney

Posted: Jun 06, 2010 01:06 PM

I have several competitors that do a ½ inch flash coat with fiberglass but most of my suppliers recommend a minimum of one inch per pass to get proper chemical reaction and yield, in fact I find not much more chemical is used to get that additional ½ inch in a one inch pass.

Also if you put in 2 inches of foam what is the advantage of an R-13 bat you could add another inch of foam for about the same cost?? R-7 foam or R-13 fiberglass that really only R-5??

Airpro

jimcoler

I've expanded my knowledge into t

Posted: Jun 06, 2010 01:53 PM

The scenario that I was talking about was of a competitor who was using a specified thickness of 1" of closed cell but when you measure their jobs, you're lucky getting 1/2" in most cases. The thickness varied greatly between 1/2" and 1 1/2" but I still don't think that's enough!

So, what does the Filtergalss do on the inside anyway? Is this just a ploy by the filterglass companies to try and keep in on the game? I think so!!! Let's look at the facts - Filterglass is down 40-60% in sales with the decline in the housing market. So they have manufacturing equipment sitting there idle for about 40-60% of the time. So, their marketing reps got together and asked, how do we keep the machines up to capacity? Their answer is to use the filterglass on the inside as a supplemental solution. But what we're finding is this isn't a solution, and it's actually hurting our industry because foam gets a bad name when moisture gets trapped in the walls.

So when you follow the practicallity of the scenario, it makes sense! Just look at the rational behind it and it makes sense!

JohnPeters

Posted: Jun 08, 2010 07:40 AM

ICC reg states that if your dealing with an air impermeable insulation medium (ie. SPF) a minimum of 3" should be applied to exterior sheathing (roof or wall).

If your competitor is pushing flash and batt (ie. Masco) they are offering an application approach that is not compliant with current code. It is my understanding that this reg. is in code because of concerns regarding securing an air seal.

On a more concerning note, anything less than 2" of CC will not provide a robust enough thermal break to stop hot from meeting cold (in climate zones 5-6). We all know what happens when hot meets cold.

jp

Gerry Wagoner

Posted: Jun 28, 2010 11:56 AM

I like the word "robust."

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