Insulating Enclosed Deck
bob regent
is approx 10' x 40' and the room covers about 20' of the length. We
installed a subfloor on top of the enclosed decking over which we will
install Pergo. We wish to insulate the floor in the enclosed area for
warmth and also to prevent moisture from reaching the finished flooring.
The patio room contractors recommended installing a vapor barrier
between the deck and subfloor. The folks at Pergo did not think this was
a good idea as moisture could get trapped between the barrier and the
deck material. Instead, they suggested insulating the joists from below
and then stapling a vapor barrier to the underside of the joists, then
finishing with exterior plywood.
The folks at the local Home Depot did not think the additional vapor
barrier was neccessary. They suggested using insulation with a vapor
barrier, with the barrier facing upward and fastened with simpson ties.
Who is right? Are there any other options? We live in Northern
California with mild temperatures, dry summers and a sometimes long and
wet rainy seasons. Thanks in advance for any assistance.
--bob
JamesBow1
barrier then finish off with exterior plywood.
home Depot doesn't build houses either.
Most of their people - at least here - have a good knowledge of what aisle
something is in but not how to apply it.
Often what I know is not what I have been taught.
That which I have learned is often the most valuable.
Trust your instincts.
Remember there is some good in everyone - just sometimes it isn't worth saving
the good if you have to put up with the rest.
Pierre Levesque
barrier on the warm side of the room.
In California it could be a little different if the room will always be air
conditioned and if the temp in the room will always be cooler than the
outside air.
But "rules of thumb" aside, vapor barriers are intended to prevent moisture
from transfering into enclosed spaces such as rooms. Moisture is carried
via thermal conductivity and thermal tranfer always flows from hot to cold.
An old professor of mine always used to say, "an open refrigerator door
doesn't let the cold get out, it let's the heat get in".
So in your enclosed porch, a heated space will carry moisture (water VAPOR
not rain or water droplets) from the interior to the exterior at night and
vice versa during the day. In extreme temperature conditions, the due point
(the point when water goes from vapor to liquid) will occur at the vapor
barrier. If the vapor barrier is against the interior wall, floor or
ceiling (where it should be), the due point will not occur since the
interior space of the room provides ventilation as does the exterior. But
if the vapor barrier is on the exterior face of the wall, floor or ceiling
(where it should not be), the due point can occur between the interior face
and the exterior an enclosed space has been created, allowing water droplets
to form, not allowing anyplace for it to escape thus being trapped and
eventually causing water damage, rot, failure, and costly repairs.
Understand that building sheathing such as TYVEK and other construction
papers are used on the exterior and many contrue these as vapor barriers.
They are not. These are breathable materials that allow water vapor to pass
through. Vapor barriers are impermeable plastic membranes (such as 6mil
poly) that completely prevent water vapor from passing through.
So your answer is..... as close to the floor as you can, between the
joists. The folks at Pergo are well intended but wrong.
Good luck,
Pierre Levesque
__________________________________________________________________________
connections architectural
a division of ConnArch Inc
http://www.connarch.com
tel. 212.982.5619
fax. 212.673.6331
__________________________________________________________________________
turtle
this sound like a chinese fire drill with no equipment.
i could not say on which should be used or not but i do know you don't put
vapor barrier and no insulation on it. this will make water or hold water.
you must have insulation between the out side and the vapor barrier.
now just reading here the pergo ideal to be a fair ideal to me. now i'm no
expert,
one thing to look at is if you have a problem with the pergo flooring and
they come to look at it for warrenty you may not get the flooring
warrentied.
just a thought from
TURTLE
danh...@infonet.isl.net
near the ground then the vapor barrier on the bottom is probably a good
idea. If it's elevated several feet with free air circulation below, then
the vapor barrier, if any, should be on TOP of the insulation. The facing
on faced insulation is probably sufficient for a vapor barrier in that
climate, but wouldn't be in a colder climate.
In any event, make sure there's a wind barrier on the bottom of the
insulation. Leaving the fiberglass exposed with no wind barrier will
reduce the insulation effectiveness considerably.
In <36328FAA...@jps.net>, bob regent <bre...@jps.net> writes:
>We just installed a patio room over an existing redwood deck. The deck
>is approx 10' x 40' and the room covers about 20' of the length. We
>installed a subfloor on top of the enclosed decking over which we will
>install Pergo. We wish to insulate the floor in the enclosed area for
>warmth and also to prevent moisture from reaching the finished flooring.
>
>The patio room contractors recommended installing a vapor barrier
>between the deck and subfloor. The folks at Pergo did not think this was
>a good idea as moisture could get trapped between the barrier and the
>deck material. Instead, they suggested insulating the joists from below
>and then stapling a vapor barrier to the underside of the joists, then
>finishing with exterior plywood.
>
>The folks at the local Home Depot did not think the additional vapor
>barrier was neccessary. They suggested using insulation with a vapor
>barrier, with the barrier facing upward and fastened with simpson ties.
>
>Who is right? Are there any other options? We live in Northern
>California with mild temperatures, dry summers and a sometimes long and
>wet rainy seasons. Thanks in advance for any assistance.
>
>--bob
>
>
>
Dan Hicks
Hey!! My advice is free -- take it for what it's worth!
http://www.millcomm.com/~danhicks
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Harry
>We just installed a patio room over an existing redwood deck. The deck
>is approx 10' x 40' and the room covers about 20' of the length. We
>installed a subfloor on top of the enclosed decking over which we will
>install Pergo. We wish to insulate the floor in the enclosed area for
>warmth and also to prevent moisture from reaching the finished flooring.
>The patio room contractors recommended installing a vapor barrier
>between the deck and subfloor. The folks at Pergo did not think this was
>a good idea as moisture could get trapped between the barrier and the
>deck material. Instead, they suggested insulating the joists from below
>and then stapling a vapor barrier to the underside of the joists, then
>finishing with exterior plywood.
>The folks at the local Home Depot did not think the additional vapor
>barrier was neccessary. They suggested using insulation with a vapor
>barrier, with the barrier facing upward and fastened with simpson ties.
>Who is right? Are there any other options? We live in Northern
>California with mild temperatures, dry summers and a sometimes long and
>wet rainy seasons. Thanks in advance for any assistance.
>--bob
Bob, go with the Home Depot suggestion. Although you could put poly
under the joists, it is only used in extreme situations and could trap
moisture between the floor and the poly. This leads to rot.
Harry
The TRUTH is out there somewhere ....
does anyone know the URL ????????????