the value of insulation

[tk]

During some brainless sort of work the other day, my mind wandered to teardrops--imagine that. I got to thinking about the actual value of insulation in a teardrop. Seems to me that, apart from those in the far North and those that pursue winter camping in harsh climates, insulation has little value as insulation.

Most home-builts seem to have either very good ventilation or AC. Those with ventilation are going to cool off very fast because of the small volume of a tear. Most of the AC builders use small residential units that still are way bigger than actually needed for a tear.

So it seems to me that the biggest utility of the insulation is in creating a matrix that increases the strength of light-weight construction, i.e., a filler. If I'm not off base about that then it makes sense to use the cheapest, lightest material for the middle of the sandwich. Thus, it would make more sense to use, for instance, bead-board as oposed to blueboard.

Any thoughts, comments, or suggestions for even cheaper material welcome.

Tom

[Gaston]

camp in the southwest , southeast or most any place the temps get over 85 and you will soon learn the value of insulation
It ain't just for winter

[mwatters]

Sure this is off-topic?

We don't go camping except in summer. Insulation isn't so much an issue for keeping warm (there are blankets and spouses for that...). But even in moderate weather the insulation is useful for preventing condensation on the walls.

mkw

[Gerdo]

I insulated my ceiling, including the hatch, and my floor. My walls are 3/4" Fiberglass Reinforced Plywood only. My thinking is that I wanted to keep the road heat out and the sun from pounding down and baking us thru the ceiling. I insulated my hatch to keep my food from baking also.

[alaska teardrop]

Tom,

I'll try to add to your thoughts in terms of cold. First on the construction: Extruded polystyrene (usually, blue-Dow or pink-Owens Corning) is the least susceptible to moisture, moisture damage (mold, ect.), compression (in fact used under concrete slabs) and physical damage such as vibration. It is also a good vapor barrier on it's own and IMO is the best value. Expanded polystyrene (usually the white beaded stuff) is much more susceptible to all of the above and has a lower R - value. All of the other insulating materials that I know of have similar issues.

There is another board insulation that you may come accross. Polyisocyanurate. Up here the brand name is R - Max and has a vapor barrier film (not to be confused with R - Tech, which is expanded polystyrene with a covering film.) The polyisocyanurate R - value is slightly higher than EXPS, however it is susceptable to the moisture damage on the edges. And speaking of vapor barrier, it is my opinion that all board insulation should be sealed where moist air can penetrate the wall, floor or roof interior cavities (i.e. everywhere).

As to all the insulation value: What you've said about climate is true. And some would say that insulating the roof is the most important, because heat rises. However, that statement is also saying that the cold follows up through the floor. Most builders in warmer climates seem to find that the mattress is sufficient. (I'm not sure that most mattress materials have a very great R - value per inch).

What to conclude from this?: If the outside temperature is below your comfortable inside temp, even an inch of extruded polystyrene in the floor would be the most helpful. A thought on that, would be to simply lay in 1" - 1 1/2" or 2" on top of the floor and then the mattress.

What you might find a bit humorous: Up here in the far north, we use a piece of blueboard on our outhouse seats. Believe me, it is most practical!

Fred

:peace:

[Sierrajack]

On the underside of my floor and in the roof, I'm using 1 1/2" pink High Density foam. IT's very easy to cut with a razor knife and snaps off clean.
You can kerf the foam for the bend of your profile and if you need to - use strips of the HD faom and fill in between with the low expansion "foam-in-a-can" and trim flush with a hack saw blade.

[madjack]

...we use no insulation in the floor and side wall...1/2 ply for the floor, 3/4 for the side walls...we do put an inch of insulation in the roof for sun protection...we figure a 4r5" mattress is plenty of insulation for the floor and other than the "butt against the cold wall" syndrome, we no reason for insulation there either...of course, everywhere(almost) that we camp is shaded and we don't haveta worry about camping in the bald assed open and subsequent environmental issues...nor do we camp often where temps go below freezing........
madjack

[Ira]

camp in the southwest , southeast or most any place the temps get over 85 and you will soon learn the value of insulation
It ain't just for winter

Bingo.

It is WAY cooler in my tear when the sun is blazing here in South Florida--with the AC OFF.

[halfdome, Danny]

Insulation on all four sides adds privacy, you hear less of them and they hear less of you Danny

[tk]

Thanks all for replies.

MKW--sorry I put this thread in off topic by accident. Somebody can certainly change it to a different forum--I don't know how.

MKW and Fred--condensation was the issue that my feeble mind was skipping over.

Gaston and Ira--yeah, I know about that kinda heat. Missouri is famous for its 95/95 days: 95F and 95% humidity. My point though was that with an AC or good ventilation that it wouldn't take long for air exchange to cool the small volume of a teardrop.

Danny--excellent point about privacy. I had never heard that one mentioned before.

Best,
Tom

[toypusher]

......................
Danny--excellent point about privacy. I had never heard that one mentioned before.
..................

Even with the windows and roof vent open, it makes a huge difference.

[sledge]

Hey now that you brought that up. do any of you guys with roof vents and fans have any problem with leaks around them.??? I never put one on, because I was afraid it would leak... ...... But I need one.

[madjack]

Hey now that you brought that up. do any of you guys with roof vents and fans have any problem with leaks around them.??? I never put one on, because I was afraid it would leak... ...... But I need one.

...as long as it installed and sealed properly, there is no reason it should leak.................

[48Rob]

Mine only leaks when I forget to close it...

Rob

[apratt]

The only problem I have with roof vents is here in the northwest, it rains!! If I have my roof vent just crack a little bit the rain always finds it way in. It would bounce off the roof then into the vent and then inside. I did add a big bubble over the vent on my 5th wheel, that It works. But would look ugly on a tear.