insulation

[Don_Papenburg]

That depends on what you plan to do . If you want to keep the outside as is  you can sdd insulation to the inside with foamboard and cover with drywall or build a wall inside the one you have and insulate to the Rvalue of choice.
 If you want to change the outside facade any way add the insulation on the outsideof the framing and then cover with new siding.

[Larry]

I done educated myself since posting the other day.  The method I was talking about is called the Airtight Drywall Approach devised by Canadian building scientist Joe Lstiburek.  He has written a few books one of which my local library had...Builders Guide to Mixed Climates.  He also has a huge website which I have been exploring....buildingscience.com.  Here is a little excert from his site about vented attics.

http://www.buildingscienceconsulting.com/topten/south.htm

Even if you don’t agree with some of his ideas I think reading his book is a “must” for anybody building a house.  I learned more about insulation and a tight house than I ever ever wanted to know.

Happy Easter all...and hope ya all find plently of eggs.

[Handy Andy]

  Regarding the wood ceilings,  when I was building in town, the city inspectors required us to install drywall before applying wood.  This was for fire protection.  Old mobile homes have paneling over studs and they just go up in a flash.  Fire that is.  Have you thought about that?  And also about the metal roof over the skip sheathing, is it just the climate that allows you to do that?  Here where it gets cold, the practice is to sheet solid, then cover with some thin insulation before applying the metal roof, if installed on a heated building.  Am I missing something?  Even on unheated buildings, the metal tends to sweat on the inside if enclosed.

[Raider Bill]

Larry,

Great link! Thanks!
I've been reading a bunch about super sealing and insulating the living space and forgetting about the dead overhead space.
In my case all my HVAC will be run from the basement up to the living area through the floor. The only ceiling openings I will have are ceiling fan, light wires and exhauset fans for baths and kitchen. Except for the exhaust  fan ductwork I will be able to foam seal the wire holes.

On another note I'm considering placing tubing along my back below grade wall which is about 8' deepand 6' wide for a geo thermo water exchanger.
I have 48 ft along that side so I figure I can get several runs totalling 500 feet of pipe or more.

[scsmith42]

Andy, there are several old buildings on my farm that have the tin installed over the skip sheathing.  I believe that you are correct re the sweating; however by allowing the bottom of the tin to "breathe" it prevents moisture from being trapped and the tin does not rust out from the inside out.

On the house photo's that I posted, I had spray foam insulation applied directly to the bottom of the tin and skip sheathing.  That will make it non condensing and also maximize it's longevity.  The insulation company will return in a few weeks to insulate the porch and tin under the eaves (portions in the photo's).

Scott

[Raider Bill]

Scott,

What do they charge per sqft for the spary in?

[scsmith42]

Bill, I don't know but I can ask.  I was fortunate in that the owner of a spray-foam insulation company is building a house near my farm, and we did a trade out (I did some grading work at his homesite and he insulated my farmhouse project).  To do the entire perimeter walls of the house 24 x 36 x 10', plus the upstairs end walls (14' tall) and the rafters(12/12 pitch - about 15' of exposed underside), he originally estimated around $3,500 - $4,000.00

Running the numbers, the house ( 24 x 36 footprint 2 story) has around 8,600 square feet of 3" insulation (lower walls), 330 square feet of 5" insulation (upstairs end walls), 1000 square feet of 6" insulation (roof), and 864 square feet of 3" insulation (upstairs floor for noise deadening).  The insulation guy recommended - whenever possible - leaving an air gap between the insulation and the drywall, versus totally filling in the space, as the airgap provides additional insulating properties by reducing thermal transfer from the foam to the drywall.  I couldn't do this on my 2 x 4 walls, but could on the 2 x 6 and roof joists.

In general, I'm told that 6" of open cell spray foam costs about three to four times the amount of 6" of fiberglass.

My insulation guy tells me that the "R" value measurement typically used for insulation is not totally applicable to spray foam, and that the actual performance is about twice the "R" rating.  I think that this is partially based upon the fact that properly applied spray foam will insulate in areas where fiberglass cant (such as behind an outlet box installed in a 2 x 4 stud), and also that it provides a complete vapor and draft barrier when properly installed.

One thing that I noticed in my farmhouse project, was that the open cell foam provides significantly more noise insulation than fiberglass.

Scott

[Raider Bill]

In my case with a ICF house I can't see skimping on my ceiling insulation. If I did the ICF's would be a waste. Through this building process I've saved some $$$ by not going timber frame and by doing all the work myself so I can and will apply that to a super insulation overhead.

[Qweaver]

Scott, the only problem that I've found with skip sheathing is the occasional rain of condensation that I will get on a sunny morning after an overnight frost.  Full sheathing with 30 lb felt over that stops that problem.  For some reason I don't have the condensation problem in my saw shed but I get a real "rain" in my motorhome shed.
Quinton

[scsmith42]

Quinton, thanks for the tip.  I'm hoping that by spraying foam 100% on the underside of the tin/skip sheathing, I will eliminate the condensing surface and prevent the "rain".

SS