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great article on energy flow in a home

2082 Views 13 Replies 7 Participants Last post by  Tom M
It has been a while since I've visited buildingscience.com, but they have a wealth of information and a new addition is an interesting read :thumbsup:

http://www.buildingscience.com/documents/insights/bsi-028-energy-flow-across-enclosures

As a followup question, has anyone seen the behaviour described in the house which was insulated...the paint failing/mold problems?
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here's another interesting article about the ''perfect wall''

every time i go there i discover im wrong about something :sad:

http://www.buildingscience.com/documents/insights/bsi-001-the-perfect-wall/2008-05-20.8834197834

no more in sulation....out sulation?:blink:
Building science is a great resource.
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Yes, in my 120 year old house. Sanded orginal siding down to bare wood and fixed everthing, primed twice and 2 coats pf paint, paint was peeling within 5 months.

Plaster walls, blown-in cellulose, wood siding nailed directley to the studs.
It has been a while since I've visited buildingscience.com, but they have a wealth of information and a new addition is an interesting read :thumbsup:

http://www.buildingscience.com/documents/insights/bsi-028-energy-flow-across-enclosures

As a followup question, has anyone seen the behaviour described in the house which was insulated...the paint failing/mold problems?
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Reactions: Tom Struble
would you then attribute the paint failure to the lack of air flow/tightness as described in the article or possibly due to a improper adhesion of the primer coat?

followup: did you correct the problem? if so, what was the remedy?
[/size]paint was peeling within 5 months.

Plaster walls, blown-in cellulose, wood siding nailed directley to the studs.
i think he's still working on it,but i guess the wedges is really your only option,i think there was a thread on here about whether its worth trying to save the old siding or not

maybe a highly flexible paint that can also ''breath'' can over come the peeling

but that would require totaly stripping the wood
with the new lead laws.....i don't know
There was a thread on another forum about rainscreen system
they showed a product that was being used that resembled corrugated cardboard ( actually plastic ) used between the first course or whatever and the same material at each stud location (This was over plywood or osb sheathing so an airspace needed to be maintained.)
the slick part I thought was a screening was over the top end of the corrugated material to exclude bugs which the wedges would not.
If I can only remember which forum that was.
I blame it on the insulation. With out the insulation I would not have those problems but, I would be darn cold.

The paint is peeling from the moisture of the interior traveling through the outside wall, condensating on the back of my siding and wicking its way out. That causes my primer and paint to pop off.

I have taken some of the orginal siding and sanded it down to brand new 1890 and even that did not take care of the peel issues. It is really poor adheasion cause from th interior moisture loss of the building.

There is no vapor barrier behind those plaster walls.
would you then attribute the paint failure to the lack of air flow/tightness as described in the article or possibly due to a improper adhesion of the primer coat?

followup: did you correct the problem? if so, what was the remedy?
Fiberglass Insulation

I found this on wikipedia thought it was interesting;

Historically, fiberglass batts became the preferred choice for residential construction in the late 20th century; it is useful to understand how this evolved, as there is no inherent advantage to batts. [Commercial and industrial construction do not use batts.] In the 1970s in response to oil price shocks, many US state governments sought to cut home heating oil usage by increasing building code insulation requirements for all new housing. At the same time, Owens Corning fiberglass lobbied intensively to convince the building officials who wrote and administered the four separate building codes then used in the USA. They also aimed to eliminate other kinds of housing insulation material (such as polyurethane) on safety or hazard grounds. The result was that Owens Corning successfully lobbied for mandatory 2" x 6" (38 x 140 mm actual dimension) wall framing with fiberglass insulation. This suited timber merchants just as well as it suited Owens Corning. Then, given the predominance of non-wind-proof cladding materials, and the prevalence of sleet (wind-blown ice) during the winters of the northern states, a need was created to ensure the whole 140 mm of fiberglass stayed ice-free and dry at all times. Building code officials also made it mandatory to fix and seal wind-and-sleet-proof sheathing under all claddings. This suited the plywood industry very well - which in turn led to the North American development of its now-massive oriented strand board (OSB) industry.
Other insulation materials present advantages in terms of stopping air, moisture migration, and recycling for sustainability not found in fiberglass batts.
Interesting but I don't believe historically correct. If the 2x6 thing was made mandatory as this said then why are we still building with 2x4's
I found this on wikipedia thought it was interesting;

Historically, fiberglass batts became the preferred choice for residential construction in the late 20th century; it is useful to understand how this evolved, as there is no inherent advantage to batts. [Commercial and industrial construction do not use batts.] In the 1970s in response to oil price shocks, many US state governments sought to cut home heating oil usage by increasing building code insulation requirements for all new housing. At the same time, Owens Corning fiberglass lobbied intensively to convince the building officials who wrote and administered the four separate building codes then used in the USA. They also aimed to eliminate other kinds of housing insulation material (such as polyurethane) on safety or hazard grounds. The result was that Owens Corning successfully lobbied for mandatory 2" x 6" (38 x 140 mm actual dimension) wall framing with fiberglass insulation. This suited timber merchants just as well as it suited Owens Corning. Then, given the predominance of non-wind-proof cladding materials, and the prevalence of sleet (wind-blown ice) during the winters of the northern states, a need was created to ensure the whole 140 mm of fiberglass stayed ice-free and dry at all times. Building code officials also made it mandatory to fix and seal wind-and-sleet-proof sheathing under all claddings. This suited the plywood industry very well - which in turn led to the North American development of its now-massive oriented strand board (OSB) industry.
Other insulation materials present advantages in terms of stopping air, moisture migration, and recycling for sustainability not found in fiberglass batts.
The exterior insulated walls have to be 2x6 for code with fiberglass
That may be a local code for you but not nationally adopted.
Walls in Maryland only need to be 2x4 and have R15 insulation. Fiberglass batts are acceptable insulation.
We are using the 2006 IRC
The exterior insulated walls have to be 2x6 for code with fiberglass
Yeah, we are R-21 with 2x4 walls we can use R15 fiberglass + R-4 ridged foam for prescriptive path
I feel the same way. It seems we created our own problems insulating drafty houses. ----Tar paper is time tested and the housewraps are not so great afterall. In fact I think house wrap should never be used unless the siding is vent or breathable. Locating the vapor barrier is getting more confusing.

From what I understand a mandatory air gap/rain screen in walls and a well ventilated attic would solve all of the issues. Then we can eliminate vapor barriers altogether or at least just let the interior paint do work.
here's another interesting article about the ''perfect wall''

every time i go there i discover im wrong about something :sad:

no more in sulation....out sulation?:blink:
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