Insulation, Radiant and Vapor Barriers - Anyone ever used Prodex insulation rolls?

This stuff is similar to the foil backed bubble wrap stuff they sell at the home centers in 4 ft wide rolls, but they claim their stuff is better. I think they are probably right by looking at the sample they mailed me.

I'm trying to insulate the floor of a cabin with no basement. its 2x8 joisted floor on posts in NH.

I use the cabin a few times a year, but would like to use it more a little more often. Presently there is no insulation at all under the floor.

This is the companies suggested installation for a crawl space

Welcome to Insulation4Less (http://www.insulation4less.com/InsulationMethods-18-Crawl-Space-click-for-Installation-Instructions.aspx)

What kind of R value do you think this installation would provide? With and without the 1 inch rigid insulation added in the diagram.

Hi mc, there are applications where the foil/bubble wrap function well, but they usually don't reach the claims that are made for them. I looked at the link and by the time you install two or three layers you could have done the same with some foil faced rigid insulation. The air gap principle is standard for any reflective surface.

I couple of tips. Rodents can and will go right through unprotected materials and if they want a nest they can make one out of bubble wrap just as well as fiberglass. So if you insulate, cover it with some osb. Also, insulating floors is a unique application. The heat in your cabin doesn't travel well down to the floor and any air leakage goes up, drawing cold air in from below. So you have a constant lack of heat compounded by a constant influx of cold air. Air seal the area well.

Also, if you have a dirt crawl space, cover it with a vapor barrier. The evaporation draws out a lot of energy and the moisture will damage the structure down there. Lap the vb up 6" onto the foundation and seal it well.

If you have an actual crawl space with a foundation perimeter, the other option would be to insulate the walls.

You can try the bubble foil products, in fact some brands come in 10' lengths which might make installation easier. Let us know which way you go and how all turns out.

Bud

Thanks Bud,
I've been wrestling with what to do with this for a few years now (since I bought the cabin)
Yes it is a dirt floor.
The building sits on large Sono tube foundations.
There is a solid skirt of some type of board (asbestos containing material I think) that encloses the crawl space, but not quite air tight.
There is limited/no access to the joists from underneath at the front of the building (as the ground slopes). The clearance ranges from less than 1 foot at the front to approx. 3 feet at the back.
I already have some damage to the joists and subfloor at the front that needs to be replaced (from the top down)

I have been planning on excavating what I can when I replace the floor and to put down a poly VB on the dirt as you suggest.
I've been told that I should provide more ventilation down there by cutting vent holes in the skirt. Do you disagree with that? (I know there are conflicting opinions on this subject)

With the moisture down there I'm concerned about enclosing the joist bays and trapping moisture in there, so was also considering filling the joist bays with rock wool insulation and enclosing it with metal lath to keep the critters out.

I've got to consider the cost as I don't use it that much in winter, and it might be cheaper just to heat it more and wear some slippers when I do? Its an A frame with a 32x24 footprint.

I'm planning to redo the flooring on the entire ground floor with a Carlisle wide plank Pine floor, so now is the time to do something about insulating if ever.
When I do the floor, should I put down a 6 mil poly VB between the subfloor and the wide plank pine?

Thanks for your help!

[QUOTE=mchristo;1631607]
There is limited/no access to the joists from underneath at the front of the building (as the ground slopes). The clearance ranges from less than 1 foot at the front to approx. 3 feet at the back.
Have you considered lifting the building, sometimes with a simple footprint it isn't too big of a deal.

I've been told that I should provide more ventilation down there by cutting vent holes in the skirt. Do you disagree with that?
Once a good VB is in place the moisture issues will be gone and venting will not be necessary. Just make sure the outside drainage doesn't flood the area, summer and winter.

I've got to consider the cost as I don't use it that much in winter, and it might be cheaper just to heat it more and wear some slippers when I do? Its an A frame with a 32x24 footprint.
A thick carpet might provide some help.

I'm planning to redo the flooring on the entire ground floor with a Carlisle wide plank Pine floor, so now is the time to do something about insulating if ever.
When I do the floor, should I put down a 6 mil poly VB between the subfloor and the wide plank pine?
Typically vapor barriers are used with buildings conditioned year round. When yours is left unheated for long periods of time there are concerns about mold and condensation. We deal with this when we look to abandon a home and move the elderly to a warmer climate for the winter. Camps however are left this way all of the time and my only thought is that they breathe well. VB's are a modern invention and have been over used. Here is a link that may help.
Energy Savers: Vapor Barriers or Vapor Diffusion Retarders (http://www.energysavers.gov/your_home/insulation_airsealing/index.cfm/mytopic=11810)

Bud

[QUOTE=Bud9051;1631680][QUOTE=mchristo;1631607]
There is limited/no access to the joists from underneath at the front of the building (as the ground slopes). The clearance ranges from less than 1 foot at the front to approx. 3 feet at the back.
Have you considered lifting the building, sometimes with a simple footprint it isn't too big of a deal.
I don't think that is an option as there is a large stone fireplace that has its foundation on the ground/ledge right in the middle of the building. I think that would be very difficult to lift.

I'm planning to redo the flooring on the entire ground floor with a Carlisle wide plank Pine floor, so now is the time to do something about insulating if ever.
When I do the floor, should I put down a 6 mil poly VB between the subfloor and the wide plank pine?
Typically vapor barriers are used with buildings conditioned year round. When yours is left unheated for long periods of time there are concerns about mold and condensation. We deal with this when we look to abandon a home and move the elderly to a warmer climate for the winter. Camps however are left this way all of the time and my only thought is that they breathe well. VB's are a modern invention and have been over used.
I am getting some mold inside the building at the front on the walls and inside the closets (above the spot where the floor joists are rotting) so I'm trying to find a way to stop the moisture from entering the building from the crawlspace. That is where the idea of VB under the pine floor comes from. If I do the VB directly on the dirt floor, maybe the VB under the Pine floor is redundant? but would it be a potential problem?

p.s. Great link! I just opened it after writing this so I appologise if I'm asking questions that will be answered after researching this site.

Thanks,
Mike.

Generally multiple VB's should be avoided, so covering the ground and then the bottom of the joists raises the question, however, as long as the side walls can pass some moisture you should be ok. If they are plastic or painted with an oil base paint you could be creating a moisture tight box which wouldn't be good.

There are several links within that link as well. Nice when information like that is made available for free.

Bud

the side walls are probably close to air tight. they are a cement board type material circa 1960 (I think containing asbestos as well) there are definitely many gaps, but not in the front where the rot problem is happening. I'm thinking of installing some mechanical ventilation to move the air to and from there while I have it all opened up to fix the floor.

thanks again for all your help. I'll post some more as I progress. (might take a while)