cabin floor insulation

[wv cabin]

hey guys I am getting ready to start insulating the floors on my cabin, it is built on 6x6 timbers and is about 2ft off the ground. I was thinking about useing that 2 inch thick fiber board insulation and cutting it to fit between to floor joists. my problem is how to attatch it to the flooring. my question is I thought about useing construction adhesive on the flooring and then press insulation onto that. has anyone tried this before? and also will the construction adhesive bond to the insulation or maybe melt it (chemical reaction). Any help would be greatly appreciated. Tim

 

[Western]

You could use bailing twine or wire. Nail to joist then tie it in place. You can also use aluminum screen or similar and attach it to the bottom of the joist to help keep bugs and critters out. May need thicker wire to keep out mice, they love living in the insulation.

 

[Cami]

I once saw a raised cabin whose floor was insulated by fiberglass batting held up with stapled chicken wire. Shanty-town enough for ya?

A friend of mine, up North, used to store hay underneath his mobile home and was pleasantly surprised to find it cured his chilly floors.

I'm a lurker on The Journal of Light Construction forums; you might want to look/ask there too.

 

[brin]

I you go to Lowes or Home Depot they have wire hangers made for that purpose they easily spring in between the floor joists under your insulation and give it support..check it out..

 

[/pine]

I can't remember what the r-value is for dead air space but it is substantially more than one would think...especially for horrizontal areas...

The floor system could be "dead-panned" with sheet material fastened to the bottom of the joists sealing and creating "dead air"

Solid wood is generally only good for about 1 r-value per inch of wood...I think dead air is about 4 times that but I will look for a chart...

 

[/pine]

I can't remember what the r-value is for dead air space but it is substantially more than one would think...especially for horrizontal areas...

The floor system could be "dead-panned" with sheet material fastened to the bottom of the joists sealing and creating "dead air"

Solid wood is generally only good for about 1 r-value per inch of wood...I think dead air is about 4 times that but I will look for a chart...

 

[studor]

I would think about running foam board insulation across the whole surface (attached with glue and/or strapping) then sealing any gaps with spray foam. This would be easier to do, create a vapour barrier and give you a higher r value because the wood would not be creating a thermal break which it would otherwise. If you are worried about critters making a home in the cavities, I would use a wire mesh or PT plywood to cover it

 

[schmism]

id go with insulated bats between joists and then cover it with blue poly tarp stapled to the joists.

 

[Travelover]

I'd definitely cover whatever you use for insulation with a wire mesh to keep out mice, squirrels, etc. They'll find the smallest holes to get in, too, so staple it carefully around the perimeter.

 

[biggerten]

Since it's rigid, leave it in 4x8 sheets and nail it to the underside of the joists. Then tape the seams to prevent drafts. It'll go up easier and faster, and be a much better job. Otherwise, go with the batts and the springy wire deals they sell for the job. The rigid foam will cost the most. Or do both, using the rigid foam to hold the batts up.

 

[schmism]

I'd definitely cover whatever you use for insulation with a wire mesh to keep out mice, squirrels, etc. They'll find the smallest holes to get in, too, so staple it carefully around the perimeter.

wire mesh wont keep mice out. unless you figure on 1/8" hardware cloth and for the cost of that you might as well just cover the bottom side with 4x8 sheets of OSB

 

[tommu56]

I used truss joists on my addition and used fiberglass stapled up in there and cut osb to lay on the top of the bottom flange of the to close it in to keep the critters out of the insulation been working for about 5 years that way.

The other part of the floor I got the panel insulation 3/4" thick that is made to fit between furring strips for doing walls.
It fit between the joist perfectly and glued it to bottom of floor in 2 layers and out a couple of nails in the joist to hold it up till the glue dried

tom

 

[dave1949]

wire mesh wont keep mice out. unless you figure on 1/8" hardware cloth and for the cost of that you might as well just cover the bottom side with 4x8 sheets of OSB

OSB isn't really mean to be an exterior exposed product. Even under a cabin it may deteriorate over time from moisture/humidity. I wonder how painted steel roofing or siding panels would hold up? They could be screwed to the underside of the joists with insulation between joists. Probably easier to work with than OSB, and you could get them pre-cut to length too. I would consider putting a vapor barrier layer in there somewhere. It really should be on the heated side of the floor. Across the bottom of the joists, it may do more harm than good. That train may have left the station already
Dave.

 

[dave1949]

hey guys I am getting ready to start insulating the floors on my cabin, it is built on 6x6 timbers and is about 2ft off the ground. I was thinking about useing that 2 inch thick fiber board insulation and cutting it to fit between to floor joists. my problem is how to attatch it to the flooring. my question is I thought about useing construction adhesive on the flooring and then press insulation onto that. has anyone tried this before? and also will the construction adhesive bond to the insulation or maybe melt it (chemical reaction). Any help would be greatly appreciated. Tim

There are special adhesives for working with foam board products. They are not more expensive - just different chemically.
Dave.

 

[ElDorado]

I too have this projects ahead of me. We have a fair amount of cabins up here on piers so I look at each cabin I get a chance to. The critters are industrious and always seem to get in and the batts seem to always end up falling.

I am in Dave1949's camp. I used metal on a few buildings so far and I have scrap sheets that the manufacture uses to protect the order as well as some that I salvaged from the junk pile. I don't have enough but my lumber yard has galvanized relatively cheap. I'm going with batt insulation and then screwing up the metal in managable sizes. This way I have easy access to wiring/plumbing in the future if/when needed.

The vapor barrier is a good idea that I had forgotten about, thanks for reminding me.

Matt

 

[Steve C]

hey guys I am getting ready to start insulating the floors on my cabin, it is built on 6x6 timbers and is about 2ft off the ground. I was thinking about useing that 2 inch thick fiber board insulation and cutting it to fit between to floor joists. my problem is how to attatch it to the flooring. my question is I thought about useing construction adhesive on the flooring and then press insulation onto that. has anyone tried this before? and also will the construction adhesive bond to the insulation or maybe melt it (chemical reaction). Any help would be greatly appreciated. Tim

If the insulation is "fiber board" then the adhesive probably won't desolve it like some plastics. It should do a great job, heat flows up and cold flows down therefore the tranmission through a floor in minimal, especially if you can stop the wind from blowing accross the bottom of it. For a vapor barrier to be effective it needs to be on the warm side of the insulation. If you decide to install one you will need to put it directly above the insulation, probably a plastic sheet? This will make the use of adhesives impossible and you will have to resort to mechanical means to hold the 2 inch fiber insulation in place.

 

[PILOON]

Get an insulation contractor to shoot foam in place.
Most effective and makes for a totally tight seal.
Probably only need 2" or so.
We did the underside of a 12' X 24' porch this way and it was good to -30 deg. and cost about $500 two years ago.

 

[bdeboer]

PL makes an adhesive specifically for foam boards. PL300 is the product.

StickWithPL - Sealants, Adhesives Products Page

Some types of rigid insulation are borate treated for insects.

Another option, although probably more expensive maybe DIY spray foam like Tiger Foam.

 

[forgeblast]

what about using the foil bubble foil insulation. First it could be stapled to the underside of the 6x6's and then you can tape the seams. This would allow you to put in bat insulation or blown in insulation. I have seen on cordwood insulation where people use sawdust and lime (masonary lime) mixed to fill voids to keep out mice.
Second i think the foil and bubble insulation deter mice from eating it. I would definatly put some type of deterent in what every insulation you were going to put there otherwise it will be over run with mice.

 

[Topstrap]

I added a 4 season room to the back of our house that is now our main living room area. It's above our patio and is open underneath. I cut 2" styrofoam to fit perfectly in between the floor joices and then used rolled insulation under that and then sealed it off underneath with some Tyvek for now to keep birds out until I put either soffit or some other finishing material. The floor stays very warm and you can be barefoot in there during the middle of winter.

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