On Tue, Sep 15, 2009 at 9:17 AM, Christina A. Snyder
wrote:
Deanne, just to remind you, insulating the inside of your stone walls
with felt, which is moisture permeable, will make the stone walls even
colder, thus causing condensation to form and stay on the stone walls
all winter, so that it becomes a perfect habitat for mold and mildew,
which will likely stain the walls and set up permanent housekeeping in
the felt, even if it doesn't make anyone sick. Sorry, but you can't
re-write physics.
You always want to design so you have your impermeable vapor barrier on
the WARM side of the insulation, which is the reverse of your plan.
There are two potential solutions:
1. Add a impermeable membrane (such as plastic) to the inside of your
interior insulation and seal it back to the stone top and bottom and at
all seams (You'll use exposed plastic over your dead body, I know).
Anything you can do to the inside surface of the felt to make it less
moisture permeable might help, such as building up a thick coat of clay
slurry over its surface in several coats, and then possibly a layer of
oil over that. Unfortunately, since you'll be removing the felt
seasonably, a clay surface would crack and leak when moved, so you'd
need to renew the surface every time it was removed. And if you did put
an oil layer on, that would make the next coating of clay not want to
adhere, so maybe the oil is a bad idea. Possibly whitewash might work,
but it is very brittle, so it it was even bumped after it dried it
would
crack and let moisture in to feed mildew. However, lime washes are
supposed to reseal if cracks if recoated. No good organic answers to
flexible, impermeable barriers, unless you can grow one like an orange
does.
2. Put your insulation on the outside of the impermeable stone, so that
it makes the stone get warmer, not colder. This will mean that you will
need to matt the outside of the felt into as smooth a surface as you
can, and treat it liberally with oils so that any rain will sheet off.
Since it touches the ground, you may also have moisture or insects get
into it from the ground, and I don't have any solutions for that.
Best wishes,
Christina
On Mon, 21 Sep 2009 22:19:35 -0400, "Deanne Bednar" <ecoartdb@gmail.com>
said:
Wow,
that is a lot of challenging news! thanks for your consideration and
details!
My vision on this is the castle made of rock with the large tapestries
which
I assumed beautified and kept the place warmer. I included some quotes
below which might give some traditional-style data.
I get what you mean regarding warm air hitting the cold and condensing.
I
haven't noticed that except during moist hot summer days that get cool
nights and the warm air condenses on the rock on the interior. I get
freaked out, but have learned it will just go away in a day or so.
I would be agreeable to plastic on the interior of the felt, or even
recycled bubblewrap if they were needed. good idea.
Maybe the SBS doesn't have much moisture since there isn't water, shower,
plants or even people usually in there.
I will bring this to the attention of the participants, and will still go
ahead with the workshop, because i an interested in how to make pillows,
cushions, etc from raw wool.
I would love to see how your project is going. It is hard to keep up
with
anything over here, and I am going through a period of discouragement,
but
that too shall pass.
3 interns now. but winter is coming. what stage are you at?
love, deanne
History of tapestries In the middle Ages, tapestries had a purely
utilitarian function. They were originally designed to protect medieval
rooms from damp and cold weather, to cover austere walls of big castles,
or
to insulate big rooms into more comfortable quarters. Tapestries used for
furnishing big stone castles were very big in size and they required big
looms, many workers and high capital investments. Thus, manufactories of
this type arose in prosperous localities, usually weaving centers. By
1500,
Flanders, especially Brussels and Bruges, had become the chief places of
production. Due to their size and intricacy, tapestries became
investments
and displays of wealth and power.
"Stone Castles replaced the earlier form of motte and bailey type
castles.
The most important building in the castle was the .
It was often cold and draughty. The was a long room
that had the lord and ladys table at the top and *tapestries* with scenes of battles
often
hung on the walls.
On Wed, Sep 23, 2009 at 1:29 AM, Christina A. Snyder
wrote:
>
You are right that keeping the amount of humidity generators (people,
plants, cooking, showering) in the SBS down in winter will help, but it
won't eliminate the condensation phenomena if you are heating the room
air so it has higher moisture capacity and you allow the warm moist air
to get behind your interior insulation next to the colder rock wall.
Even the woodstove burning wood releases moisture, though most goes up
the chimney.
The condensation phenomena is identical to that at UHEAC, where the
homemade insulating curtains in the presentation room cause lots of
condensation on the window glass because they make the window colder yet
don't seal the room air away from the window. The room air is constantly
flowing down past the window being dehumidified as it cools. Yet the
same building has an example of good interior insulation in the kitchen/
sitting area, where the insulation has a vapor impermable layer on the
inside and seals to the edges of the cold window in a track, thus no
significant condensation develops. The more you can replicate those
features of in your design, the happier you'll be.
I've not lived in many castles, though I've visited lots, and many did
have condensation problems. I'll bet that where they put a tapestry in
the middle of an exterior wall they had condensation and even
mold/mildew problems. If they managed to make the tapestry cover the
whole wall and fit tightly to the edges, they probably had less
problems. Like the SBS, they had little sources of humidity in most
castle rooms, since they didn't have showers or plants, cooking wasn't
done in the living spaces, so people were the only sources. Since they
didn't have glass windows in medieval times when those tapestries were
made, the interior humidity couldn't really get much above they dry
winter air outside. I'll bet a lot of historic tapestries were lost to
mold/mildew when people began adding windows. Maybe they eventually
learned to hang decorative tapestries farther from the cold surfaces,
even though that would have reduced protection against heat loss. They
also made and lived in small tapestry tents within the larger cold stone
rooms, such as inglenooks and canopy beds - since these draperies
weren't against the cold surfaces they wouldn't have had nearly the same
mildew issues.
You are right, summer condensation isn't much of a problem since we
don't have absorbant materials against the cold wall surfaces then, and
because it does go away as soon as the humidity in the air drops. But in
winter in a poorly insulated building (or portion thereof), even
furnishings like beds and couches pushed against cold walls can cause
mildew to form on both the walls and the furnishings, as we've
discovered to our sorrow in this old farmhouse. The moisture on the cold
surface builds up over weeks and doesn't go away for months, so the
mildew has everything it needs: moisture, organic material to eat,
oxygen, and temps above freezing = population explosion! I didn't want
to rain on your parade, but thought if you were forewarned you might be
able to design your insulation so as to deprive these micro-organisms of
at least one of the things they need to thrive, like the moisture. Its a
lot easier to prevent the growth than to kill it off once established.
I doubt you'd find the garage we are just finishing very exciting, but
we'll get to the house this next year. Hope this finds you well!
Christina
Dear Christina,
Thanks again for your thoughtful input !
Another thought I had about the castles is that they probably had almost
NO heat in them...to cause condensation. Just guessing of course.
I do remember the conversations from the past about keeping the thermal
loops from bringing hot, moist air up under the felt/insulation
layer....and the need to make it fit tight....that is something I have kept in mind. It probably would have been wise to cut up an old army blanket and experiment for the previous winter to see how it preformed before going ahead...but I want to make length of this wool felt anyway, and can use it for cushions on things. Kylie wants to
present at the Natural Building Colloquium East next year on this, so it is also
furthering her goals. A couple from MSU are building a yurt and are
geeked...plus some others...so those things are valuable in themselves.
>
Glad to hear the update on your garage, and will definetly check your
house
building out next year ! ! !
On Thu, Sep 24, 2009 at 10:15 AM, Christina A. Snyder wrote:
Experimenting with a couple of different insulation designs is a great
idea to see what works best, w/out wasting much materials. Center of
insulation results will likely be different from edge effects, so don't
make the test pieces too small.
Castles did have fireplaces in at least the rooms of the wealthy, and of
course the kitchen. But without tight windows (oiled parchment was used
before glass), the fire would actually make the rest of the room colder
by pulling in more outside air, so you'd only experience warmth if
sitting almost in the fire. When thermal mass stoves appeared, it was
better, cause a short intense burn could heat up the stove mass, then
when the fire was out it wouldn't pull in more cold air, but the heat
kept radiating from the mass. Some stoves were built with the bed
platform on top.
Best wishes,
Christina
9/24/09
Beautiful response, Christina,
What a rich and fair mind and heart you have.
Love you,
Deanne