Pros/Cons Tyvek housewrap
George R.
asked him about it and if I could do it myself. He said he
doesn't bother with it. He says that housewrap makes the house
too tight. When you close a door the windows bow out and in the
winter time the inside of the house can trap chemicals and other
airborne stuff potentially causing all kinds of upper
respiratory problems with those so afflicted (not I). In other
words, the house can't breath and may become stuffy on occasion.
He said if I wanted it I could have him do it or I could do it
myself. I live in Ohio. I didn't understand what he was saying
in regards to Tyvek about some builders who use to use 1" foam
instead of plywood sheathing. He uses wood all the way around??
Does this mean that some builders use to use the 1" foam in
place of plywood sheathing, seems cheap. So is Tyvek worth it on
homes constructed in the new millennium? The insulation and
windows in new homes nowadays seem far superior to that of 15
years ago, R19 in the walls and R30 in the ceiling, with windows
enclosed with special gas. I realize that housewrap is not an
insulator but an air barrier. The new home will be a colonial
and about 2700 sq/ft.
Thoughts?
Remove NOSPAM if replying privately.
Thanks,
George
Peter Baumgarten
escape of inside air from inside the building wall envelope. Some air
has to exchange to remove stale and contaminated air, and I wish I knew
what amount. Maybe 2 changes of air per hour? That is 2400 x 8 /2 /60 =
160 cu ft/min., which in a way is a lot, and on a windy day it may be
more. Would excellent caulking around windows and doors, and between
wood siding and concrete foundation and the attic structure do the same
thing? You also need a tight heat air handling system (house wrap
wouldn't cure that).
In other words I don't have a simple answere for you. The company I
represent, K-X Faswall (see http://www.faswall.com) provides breathable
wood concrete wall forms for concrete posts and beam construction.
Michael Bruss
: I'm building a new home and specs do not call for a housewrap. I
: asked him about it and if I could do it myself. He said he
: doesn't bother with it. He says that housewrap makes the house
: too tight. When you close a door the windows bow out and in the
: winter time the inside of the house can trap chemicals and other
: airborne stuff potentially causing all kinds of upper
: respiratory problems with those so afflicted (not I). In other
: words, the house can't breath and may become stuffy on occasion.
: He said if I wanted it I could have him do it or I could do it
: myself. I live in Ohio. I didn't understand what he was saying
: in regards to Tyvek about some builders who use to use 1" foam
: instead of plywood sheathing. He uses wood all the way around??
: Does this mean that some builders use to use the 1" foam in
: place of plywood sheathing, seems cheap. So is Tyvek worth it on
: homes constructed in the new millennium? The insulation and
: windows in new homes nowadays seem far superior to that of 15
: years ago, R19 in the walls and R30 in the ceiling, with windows
: enclosed with special gas. I realize that housewrap is not an
: insulator but an air barrier. The new home will be a colonial
: and about 2700 sq/ft.
Tyvek will not only minimize air movement through the walls, but will help
protect the sheathing and framing in the event that water penetrates the
outer covering of the house. If you decide the house is too tight, open a
window. It's far easier to let more air into a tight house, than it is to
go back and fix one that's too leaky.
Mike
John Barry
The wrap forms a system with the vapor-barrier on the inside, to
controllably allow moisture diffusing through your walls a place to go,
without allowing the airflow that would otherwise occur.
Most houses have substantial airflow through, via the odd gaps all over. If
there's insufficient airflow, the ideal way to provide it is an air-to-air
heat-exchanger. Which gives a controlled flow-rate, and normally recovers
75-80% of the energy that would otherwise have been lost.
Energy is becoming more valuable.
Regards,
John
"George R." <NOSPAMr...@ncweb.com> wrote in message
news:seni3m...@corp.supernews.com...
> I'm building a new home and specs do not call for a housewrap. I
> asked him about it and if I could do it myself. He said he
> doesn't bother with it. He says that housewrap makes the house
> too tight. When you close a door the windows bow out and in the
> winter time the inside of the house can trap chemicals and other
> airborne stuff potentially causing all kinds of upper
> respiratory problems with those so afflicted (not I). In other
> words, the house can't breath and may become stuffy on occasion.
> He said if I wanted it I could have him do it or I could do it
> myself. I live in Ohio. I didn't understand what he was saying
> in regards to Tyvek about some builders who use to use 1" foam
> instead of plywood sheathing. He uses wood all the way around??
> Does this mean that some builders use to use the 1" foam in
> place of plywood sheathing, seems cheap. So is Tyvek worth it on
> homes constructed in the new millennium? The insulation and
> windows in new homes nowadays seem far superior to that of 15
> years ago, R19 in the walls and R30 in the ceiling, with windows
> enclosed with special gas. I realize that housewrap is not an
> insulator but an air barrier. The new home will be a colonial
> and about 2700 sq/ft.
WriterAlan
I read the other day in a really old issue of Modern Maturity that about 80
percent of heat loss is through the ceiling, only 15 percent is lost through
the walls, and that includes windows and doors, and 5 or less through the
floor or elsewhere.
In strictly economic terms, why should one install Tyvek or a tyvek-like
material if it is only going to amount to, I'm guessing here, a 10 percent
reduction in heat loss?
WriterAlan
Rusty
>: in regards to Tyvek about some builders who use to use 1" foam
>: instead of plywood sheathing. He uses wood all the way around??
>: Does this mean that some builders use to use the 1" foam in
>: place of plywood sheathing, seems cheap.
>:
I volunteer with Habitat for Humanity and we used to use 1-1/2" of
Styrofoam (here in Canada) on the ouside but no sheathing - just
galvanised steel T-bars let in to the studs diagonally as wind
bracing. We don't do this any longer as we don't consider it
adequate. We have gone back to 3/8" or 7/16" OSB sheathing
(whichever we can get the cheapest or free!) It not only gives a
much more rigid house but it makes the walls much harder to cut
through with a Stanley knife if you wanted to break in. Just think
about it. If you have vinyl siding, Styrofoam, fibreglass and
drywall it is fairly easy to cut through the lot with a Stanley
knife and a boot and you are in the house. Most people can squeeze
between studs on 16" centres.
G Mulcaster
<NOSPAMr...@ncweb.com> wrote:
>I'm building a new home and specs do not call for a housewrap. I
>asked him about it and if I could do it myself. He said he
>doesn't bother with it. He says that housewrap makes the house
>too tight.
Here are quotes from Keeping The Heat In published by Natural
Resources Canada Office of Energy Efficiency (an excellent, free
publication ):
The wind barrier is located on the outside of the envelope to protect
the insulation from the circulation of outside air. Standard building
materials such as exterior sheathing and building paper or new sheet
materials such as spun-bonded olefin (Tyvec?) act as the exterior wind
barrier.
The air barrier blocks air flow from the inside to the outside. ...
The air barrier can be installed at any location in the envelope.
Usually it's installed on the inside of the envelope, where it is kept
warm. This protects the material from temperature changes which can
affect its durability. When installed on the warm side, the air
barrier is often combined with the vapor barrier. If located on the
inside, the air barrier will also prevent conductive heat loss when
air circulates from the house to the wall space.
End quotes
From the above, my $0.02 is that Tyvec, being a wind barrier, will
not contibute substantially to your house being too airtight. On the
other hand, you should have some form of wind barrier such as building
paper (tarpaper?) or Tyvec over the sheathing.
Regards, Gary
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Thomas G. Baker
reported on tests of various "house wrap" and on building paper. House
wraps were found, by this test, to hold more moisture and dry more slowly
than 30 pound building paper. Neither type of material should make the
house "too tight", but either would help seal against moisture that
penetrates the outer skin.
TB
TW
Heat loss = apples; air-infiltration = oranges.
Both are fruit, but still different.
John Barry
In fact, long term, the purpose of the outer wrap, in conjunction with the
interior vapor barrier, is to allow the moisture that gets into the wall
cavity in winter to leave over the course of the year. The wrap has notably
higher permeability to water vapor than the vb.
Holding moisture in the wrap would seem to be a totally separate issue, like
to not rot the siding when hurricanes or such blow moisture into the wrap,
or flashing etc. is incorrectly done.
Lotsa good research pamphlets available from GPO for many years now on the
subject of insulation/moisture control.
Regards,
John
"Thomas G. Baker" <tgb...@mindspring.com> wrote in message
news:38ED5B3A...@mindspring.com...
William Chapman
this thread..so here goes...
First of all, there is no building on earth that does not need a breathable
wall system. If humans inhabit such buildings, moisture vapor will be generated
and need a place to escape. With the exception of the newer wall designs like
Blue Max, that utilize an air exchanger, there is no real need for Tyvek.
Also, we, I think, have discussed the vapor barrier issue in this newsgroup
before. Down south, vapor barriers on the warm side of the wall are deadly.
This causes alot of condensation, due to the dew point down here. Up north
however, vapor barriers are a good idea.
Tyvek works like this:
liquid molecules = large and bond together covalently
air molecules = large and bond together
vapor molecules = small and in an excited state
Dupont created a spun (not woven) web that allows the vapor to pass but not air
or water. It makes sense to me to put something like that on my house...Do you
go out in the rain with just a sweater (insulation) on???? Nope, you put on that
windbreaker (probably made of Goretex, which breathes similar to Tyvek)
Anyway, Tyvek has a perm value of 58. Highest in the industry of all the
wraps. Felt paper has a perm value of 5....code minimum. 30 pound felt DOES
NOT repel water better than the housewraps...Think about it...paper or
plastic???? Go back and read the article..I have plenty of articles from JLC
and Fine Homebuilding that support the use of housewraps...
My two cents worth,
Bill Chapman
Regional Product Manager
Dupont Tyvek Weatherization Systems
Knoxville, TN
P.S. Isnt it great that we can all agree to disagree???
Larry Pruitt Jr
done, he should not do it get someone else or do it yourself. you need to
look into a heat/air exchanger a new house of your size should have one.
If one is not in the plans get it planned before the heat & air people get
there to install the vents /furnace or heatpump.
> asked him about it and if I could do it myself. He said he
> doesn't bother with it. He says that housewrap makes the house
> winter time the inside of the house can trap chemicals and other
> airborne stuff potentially causing all kinds of upper
> respiratory problems with those so afflicted (not I). In other
> words, the house can't breath and may become stuffy on occasion.
> myself. I live in Ohio. I didn't understand what he was saying
> in regards to Tyvek about some builders who use to use 1" foam
> instead of plywood sheathing. He uses wood all the way around??
> Does this mean that some builders use to use the 1" foam in