Is more insulation the answer here

[Randyj]

I recalled reading the subject of insulation and moisture problems in Florida a few months ago so I'll post a link to an article on the subject here.
http://www.rlcengineering.com/sprayfoam.htm

Thinking about using the sprayed in foam myself...or how I can incorporate it into my design or if it is necessary for me to do so.

[DIY]

comment to all:

1.) Climate,
2.) where the building is, and
3.) how it was built,
are necessary to know.
All of the above except for location and climate was addressed in my first post regarding this thread.
Do we agree?Not my intention to post here whether people agree or not its all about sharing knowledge ,experience and advice whether accepted or not.Perhaps ALL threads and ALL queries should explain as early as the first post, where they are, in terms of climate or geography.

DAvid

p.s. R40 sounds like a lot to me, for an attic in a Florida house, especially when I think about how the rest of house was likely to have been built.

Your thoughts on how the rest of the house was built? The insulation companys that evaluated to mentioned nothing of R40.

[geniescience]

in climates far north of Florida, people wrap the unfinished house in a breathable sheet -- a housewrap -- which lets humidity evaporate but does not let wind or air pressure through.

Any house built on site with 2x4's, stick built, will have hundreds of seams and (small) openings that let air push through, whenever any wind or air pressure is present. These gaps / leaks / openings all become a significant factor in calculating what to do in terms of HVAC, heating, cooling, etc.

All heating or cooling creates air pressure, since air density changes; heated air wil push up, cooled air down. Since your house is likely to have been built to local building standards, you have a "leaky" house -- which is not a serious problem in your climate.

However, you mentioned above that you would put R40 in the attic. (!).

On Feb 2nd at 9:31 PM you said "Seems the next step would be to blow in or roll in an insulation value of R40 ,and go from there... Thanks for all the replys and advice again all! Much appreciated."
-- That sounded like you were gone, done, finished, and gone off to order an installation of R40 ....

Hope that clarifies a bit.

Another thing you have in your climate, as in most, is a house built in direct contact with the foundation. Far north of Florida, people put a plastic bubble wrap (as a heat break / insulator), on top of the concrete walls of the foundation, and then lay the first sill plate of the entire house on top of that. See FoamSealR™ sill gasket using any search engine. I have a roll of it on my desk, 5.5" x 82" which cost me $5. It prevents air infiltration and it slows down the inevitable heat transfer from the (heated) house to the (cold) foundation. Heat-cold transfer works both ways -- cool house, hot foundation.

So, R40 sounds like a lot for an attic when the rest of the house is what it probably is.

New topic: Foam is far better than "batts".

David

[jadnashua]

My comment on R40 did not directly relate to places like Florida, but stated that some parts of the country require this. A bunch of heat is lost when it rises, so the easier place to insulate is the attic. How much, is up to a cost/benefit review. This can help for cooling loads as well, although a radiant barrier there probably helps more. I know that I have both a radiant barrier and about R40 in my attic. The radiant barrier is on the underside of the roof joists, and the batts are on the ceiling of the top floor. In the summer, prior to the radiant barrier, the ceilings were hot at the end fo the day. Now, they are "room" temperature. Traditional insulation slows the transfer of heat - a radiant barrier can redirect that energy - back into the house in the winter, and back out the roof in the summer.

Tightening up the house has its good and bad points. A truely tight house will have moisture and pollution problems unless addressed (controlled air exchange). A really loose one will cost a bunch to condition.

[geniescience]

.... I have both a radiant barrier and about R40 in my attic. The radiant barrier is on the underside of the roof joists, and the batts are on the ceiling of the top floor. ..... a radiant barrier can redirect that energy - back into the house in the winter, and back out the roof in the summer.

Well said. A radiant barrier redirects a lot of the heat radiating from the sun to earth, like what a mirror does to light waves, whereas as all other types of heat insulation do something totally different: they slow heat transfer down to a lower rate.

My comment on R40 did not directly relate to places like Florida ....

-- I wonder if there is a way to make it automatic that people have to mention their climate they are in, after they describe their problem. It's critical in most situations dealt with in these forums.

David

[scottstrodel]

Hopefully, you've resolved your situation. Just a note concerning concrete block walls; I am a unit owner and the board president of a 1962 built, 49 unit condominium complex in the Seattle area which is constructed of concrete block walls. One concern I have come across (not sure about Florida) from an engineer concerned a similar building where all the metal single paned windows were replaced with energy efficient vinyl double pane glass.

Previously, the interior unit moisture would condense on the colder metal window frames and glass. After the new windows, the interior moisture began to condense behind the walls (hidden) where the air came into contact with the cooler exterior sheathing of the concrete block. This moisture along with a nice food source (framing wood, sheetrock paper, etc.) brought about some problematic mold issues.

So be cognizant of your vapor barriers or lack of when considering insulating or sealing the envelope of your home if it has similar temperature concerns inside/outside.