Under floor insulation.What's best?

ben2go · January 23, 2009, 10:23:35 PM

I really don't want to use fiberglass insulation under my floor.I will be covering a liquid radiant heating plumbing, as well as the drains and water lines.I will be using a vapor barrier under my house, but we have high humidity.My foundation does have vents but I am still concerned that enough moister will get in and cause the insulation to fall.I do plan to use a breathable mesh to cover the bottom of the floor joist.I am also using gutters and a rain catchment system to help keep water away from the sides of the foundation.I'm also using 16 inch over hangs.What would be the best bang for the buck?I have considered cotton bat(AKA denum),cellulous,and spray foam.Is there something else out there?I am planning to do the installation myself.I have blown insulation and I have sprayed foam in industrial applications.Open to all ideas.

rwanders · January 23, 2009, 10:51:23 PM

I would go for closed cell polyurethane foam----if you can get someone to rent you the equipment and DIY, even better. Enough depth to gain the impermeability and you won't need a separate vapor barrier either.

Good Stuff!

January 24, 2009, 08:23:40 AM

Yep, look up your local Icynene rep and give him a call. I used it to completely envelop my house and I love it.
Okie Bob

glenn kangiser · January 24, 2009, 12:13:42 PM

I think you should get and Icynene suit made, BoB.

FrankInWI · January 24, 2009, 12:51:26 PM

that sprayed foam is so darned expensive though.... really wanted to do that on my roof, but chickened out cause of the $$. Course truth be told, now I wish I whould have...... Not that anything is wrong with the pressure blown moisturized cellulose, but I am concerned with future moisture on my low angle roof that holds a lot of snow when it isn't heated.

January 24, 2009, 05:20:10 PM

I would like to do the entire house in spray foam but we are on a very limited budget.I'll check to see what the price will be.I can get the foam from a boat supply house at a slight discount.Don't know if it would be cheaper that way.Renting the equipment will be tricky.My area is far behind when it comes to building technology.Some contractors I talk to didn't even know that a house could be spray foamed.They ask me how many thousands of cans would it take.

Beavers · January 24, 2009, 07:49:57 PM

It ain't cheap! I just got a quote of $1200 for spray in foam R-28 for the floor of my 14x24.

I'm now leaning towards a concrete block crawlspace. Once I factor in the cost of the insulation, (not even including skirting) the post and pier is more $$$ than the crawlspace.

Okie_Bob · January 25, 2009, 10:39:59 AM

Glenn, don't you think Icynene should send me commission payments?

I do!
For those that decided against Icynene and now wish they had gone ahead, I say, yep, you should have! I bit the bullet
and sure am happy with the product. Since I used it in new construction, I have no record to compare the savings or the ROI
with any exactness. But, I have been pleasently surprised at how low my heating costs have been this year. I can only attribute
it to my excellent building skills and Icynene!!!! (I'm KIDDING about my skills, NOT about the Icynene)
Okie Bob

glenn kangiser · January 25, 2009, 03:53:32 PM

I bet the skills are good too, BoB. Yes - You have sold more Icynene that anyone on our forum. You deserve a check.

January 25, 2009, 04:16:26 PM

glenn kangiser · January 25, 2009, 04:24:01 PM

Always a wiseacre around.

Bill Houghton · January 25, 2009, 05:02:32 PM

Quote from: glenn kangiser on January 25, 2009, 03:53:32 PM
I bet the skills are good too, BoB. Yes - You have sold more Icynene that anyone on our forum. You deserve a check.

I hope you dont' mind me chiming in here. We built this house 6 years ago and used Icynene everywhere we could. Walls, ceiling (sprayd down on top of the drywall), garage, etc... Our heating bills are low and the house is very quiet. When we built the house there wasn't an applicator within our area. The company we used (Kulp's of Stratford) sent a crew of 4 guys and they did a fantastic job. Worked hard, wasted no time, were polite and cleaned up after themselves. We have two companies within a couple of hours of here now. I talked with one on Friday to give them notice that we are planning on using Icynene in our cottage project this summer.

Bill in the U.P.

glenn kangiser · January 25, 2009, 05:17:52 PM

Good to know, Bill. BoB likes supporters.

Bill Houghton · January 25, 2009, 08:00:19 PM

Glenn,

I have an idea on using Icynene on my ceiling. I was thinking of making a kind of drop ceiling, suspending 2 x 4's a few inches below the bottom cord of my trusses. Put cardboard or paneling of some sort (read thin) on the bottom of the truss bottom cords first (where the ceiling is normally anchored), then after all of the wiring, etc... have Icynene sprayed in the cavity. That would leave the attic space for even more insulation (blown in) and have the Icynene to prevent warm air from escaping upward. I know this is overkill (I love overkill espeically in insulation). I am planning on 18" energy heels on my trusses.

I think this will be OK as long as I have the turss strong enough to handle the dead load of the extra framing, the foam, and the T & G 3/4" we are planning.

What do you think? This is going to be a pole style building, so I am planning on leaving the poles long so I can still have 8' ceilings. The walls will be 6 x 6 poles with 2 x 4's flat on the outside and inside, making the walls about 8 1/2 thick for insulation.

(Did I mention that I love well insulated buildings?)

Bill in the U.P.

glenn kangiser · January 26, 2009, 12:36:17 AM

I think the U.P. is a good place for lots of insulation. Sounds like it would work good Bill.