Best method to insulate floor

[Torque1st]

Hello gentlemen-

What is the best way to insulate a wood floor over a crawlspace? The building is 14 x 24' located in Kansas City. The floor joists are 2x10" on 16" centers. The building is heated and air-conditioned. The only access to the crawlspace is a 24x30" opening in the floor. The perimeter foundation is 8" thick PC. There is approximately 16" of space under the joists near the access hole and 36" of space at the far end of the building. There presently is no insulation under the wood floor.

I was thinking 2" of foam sprayed in but I do not know if a contractor could access that space and I am concerned with safety and a breathable air supply. I know foam would be beyond my abilities.

I am getting a mite long in the tooth to crawl under there besides being stiff and over-sized to boot. It was hell getting under there when I was younger.

 

[walrus]

Hello gentlemen-

What is the best way to insulate a wood floor over a crawlspace? The building is 14 x 24' located in Kansas City. The floor joists are 2x10" on 16" centers. The building is heated and air-conditioned. The only access to the crawlspace is a 24x30" opening in the floor. The perimeter foundation is 8" thick PC. There is approximately 16" of space under the joists near the access hole and 36" of space at the far end of the building. There presently is no insulation under the wood floor.

I was thinking 2" of foam sprayed in but I do not know if a contractor could access that space and I am concerned with safety and a breathable air supply. I know foam would be beyond my abilities.

I am getting a mite long in the tooth to crawl under there besides being stiff and over-sized to boot. It was hell getting under there when I was younger.

Foam would be the best, I was watching "this Old House" the other day and watched them spray open cell foam, the guy spraying had live air coming into the back of his suit so I wouldn't worry about air under there. I 'd think you'd want closed cell foam but..... Is it a dirt floor?

 

[Carsonb]

Foam but be sure it's also a vapor barrier type which is a closed cell. It could be done conventionally if the plastic was laid before the subfloor, then you could have Roxul or fiberglass put in. Roxul is just nicer to work with more R value and fits snuggly instead of sagging. Both would need some kind of strapping.

 

[Torque1st]

It is a wooden floor above a crawlspace that is over dirt.

This structure was built in 1967. There is no vapor barrier in the floor.

 

[Torque1st]

Any other ideas or suggestions?

Anyone venture a guess on what a job like this would run?

When measuring for 2" foam insulation is that considered an average thickness or a minimum thickness?

That dirt floor will make crawling around with a moon-suit on and air supply difficult.

 

[walrus]

Any other ideas or suggestions?

If it was mine and I could get in there, I'd do R19 fiberglass with 4 by 8 sheets of 2" foam on the face of the joists. Caulk or canned foam the joints. Make a huge difference in the comfort of the floor. Thats assuming you could get in there with the foam?. Spray foam around here is over a buck a board foot so you're looking at quite a chunk of change to get it sprayed

 

[Torque1st]

Thanks!

That access opening is only 24 x 30" and it is against a wall so operational room is extremely limited.

The area is 336 Sq Ft and at 2" thick, so 672 Sq Ft ~$700 plus??? That would be a chunk of change. Getting it done may be worth it. Of course I would still have to get my old stiff carcass down there to inspect the work, maybe more than once.

 

[Deltarat]

My house has regular batt insulation between the joists with chicken wire stapled under it. It's been there since the 60s.

 

[nate379]

Most houses around here they they don't insulate the floor. Just the walls of the crawlspace and that's it. Crawlspace normally is 4-5ft from ground to floor joists though.

 

[Torque1st]

I wish they had excavated a bit when they built this building. There is still old dead grass down there. The concrete foundation walls are not insulated. The walls above are insulated as is the ceiling but the floor is cold.

Insulating the rim joist and foundation walls is an option.

The chicken wire is a good idea to hold up insulation. I have wondered about nails and plain wire also. There are stiff wires that can be pushed up in between the joists also. What was done for a vapor barrier?

 

[Carsonb]

We've insulated crawlspaces by installing the vapor barrier over the joists and up into the cavity then up again and over the next taking good care to seal the edges. Chicken wire is a serious PIA to work with in confined spaces they use it on school portable classrooms. It works very well but you're not goning to have any helpful friends fast! I'd just strap it up with wire or even plastic twine like they sell for hay balers but use alot so there's no sagging.
Insulating the exterior wall is a good idea tack and glue on tar paper then fiberglass then vapor barrier or use foam board if you can get it in. Then spread thick plastic on the floor or ground

 

[aim]

If the money is there. Spray foam all the way. That stuff is the cats meow.
It's pretty pricey but I don't believe there is a BETTER way to go. 1" of foam is better than 6" of saggy damp fiberglass.

 

[GSSFC]

Any other ideas or suggestions?

Anyone venture a guess on what a job like this would run?

When measuring for 2" foam insulation is that considered an average thickness or a minimum thickness?

That dirt floor will make crawling around with a moon-suit on and air supply difficult.

About $650. That sounds like a tight but doable area.

Tim

 

[Torque1st]

Thanks Tim!

It looks like I had better talk to a contractor.

I have a soffit area around a sunroom that needs insulation also. They could do both at once.

Happy New Year guys!