Root Cellar Remodel, Split Level Storage, Shop, Shed Pole Building on a Foundation

[Depmandog]

Okay. How big of a deal is the moisture barrier on the insulation? The reason I ask is because the reason I was thinking of installing the insulation first is so that I could put the moisture barrier side of the insulation up.

The downstairs will not be heated, but I hope that it stays above freezing due to the natural temperature regulating tendencies of being in the ground. The upstairs will be heated periodically. Is it going to be a big deal if I put the insulation in "upsidedown" from the basement side later?

You aren't planning on heating the space 24/7 during the winter....so I assume at times the upstairs will be colder then the downstairs, and visa versa when you heat the upstairs. Normally, the vapor barrier would go on the warm side....and I was ready to recommend installing 6 mil plastic between your joists and the subfloor as your vapor barrier. BUT, after thinking about your situation - I am scratching my head. Almost leaning towards no vapor barrier, and suggesting you might want to run a dehumidifier at times (sometimes upstairs / sometimes downstairs depending on the conditions), if needed.

Tad worried that the vapor barrier will condensate no matter what side you put it on. So let the moisture pass thru - use dehumidification as needed - that's my best guess, which is what I think you might have been thinking also.

 

[Iplayfarmer]

I had considered double vapor barriers, but I hadn't considered no vapor barrier. The upstairs will be heated only when I'm out there. At the most that would be about 12 hours on a Saturday and maybe 4 hours a few nights a week. The other factor to consider is that I'm installing windows intentionally to take advantage of the greenhouse effect and hopefully raise the temperature of the workshop a few degrees.

I'd love to hear any input on the subject. Maybe Eddie Walker is watching this thread and will chime in. He usually seems to have good advice when it comes to this kind of thing.

 

[Depmandog]

I went back and re-read your intended use for the basement area...and you mentioned above freezing storage area for paint and the like.

I would treat this identical to a house build. Vapor barrier on all exterior walls and main floor ceiling. No vapor barrier between the basement and the main floor. Insulating the floor joists with unfaced insulation.

Like any basement, it may be necessary to dehumidify it during the summer to keep things from rusting.

I definitely would not use a double vapor barrier, that's asking for wet insulation.

 

[radioman]

first, I want to say that I wouldnt worry about the chimney framing. As long your are 16 or 24 OC, you can just put pipe in between with insulated pipe. if it at an angle, they have elbows if needed on stove. I bet once you find the stove, the solution will present it self.

As for insulation, as long you can get the roof to breathe, and insulate it with whatever you have. if it kraft faced, then thats all you need for a shop. If it uncovered, plastic will do on warm side but I recommend covering it up with drywall for safety.

 

[Iplayfarmer]

I have an update on the shingles project from Mrs. Iplayfarmer and I have some more discussion about the insulation.

First the shingles update. Mrs. Iplayfarmer has declared that she likes the random pattern of shingles the best. That's probably what I'll do.

Now for the insulation debate. I'm very interested in any comments because this is a unique situation. There are three parts to this discussion: Climate, Structure and Schedule.

Climate: Idaho is very arid, but can get very cold. We don't typically have a lot of moisture in the air. For instance, today is about 25% humidity, and we just got rain over the weekend. We don't have the condensation problems that coastal areas and southern climates have. But we do get very cold. There's potential for a 80 *F differential in temperature if it's -20 *F outside and I heat the shop to 60 *F to work in. That is the purpose of this smaller insluated shop. I want a small space that is easy to heat so I can be comfortable working there in the winter.

Structure: Only a part of the workshop is over the basement. The rest of the floor is open to the atmosphere. I'll include a picture for reference below. About half of my floor is going to be over the basement that hopefully stays above freezing in the winter. The other part of the floor is going to be over the open air.

Schedule: As mentioned before, the workshop will only be heated periodically. I gave a best case scenario of 12 hours on Saturdays and 4 hours a few nights a week. A more realistic estimate is about 6 hours on Saturdays and maybe 2 hours at night twice a week. The rest of the time the workshop will be left to fluctuate to whatever temperature Mother Nature dishes out.

The question comes down to this... Do I need a vapor barrier and should it be up or down?

 

[NormL]

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The question comes down to this... Do I need a vapor barrier and should it be up or down?

The folks who could have the best advice for you are the manufacturers / marketers of mobile homes in your region. My thoughts are that they can help you with something like what is used on the home we live in. The dealer called it a "belly wrap". The entire underside of the mobile home is covered with this material which looks similar to what plastic tarps are made of. I'm not sure it is totally waterproof. My guess is it can breath. I can't tell you if there is a vapour barrier between the floor and the insulation or not. Maybe someone on the forum can speak to that. Also, the area of your floor which is covering your "basement" may need to be treated differently.

 

[Iplayfarmer]

Here is the progress I made last night. I got all of the cross nailing done on the joist hangers. Then I got some of the blocking installed. I ran out of daylight before I got it done. (The pictures were taken this morning.) Hopefully I can get some more done tonight. I would have done more, but I took advantage of some very nice weather and rode my horse for a while when I first got home from work.

 

[BeezFun]

The question comes down to this... Do I need a vapor barrier and should it be up or down?

You already have a vapor barrier, the plywood on the floor. Plywood is classified as impermeable, just like plastic or Kraft paper. You might want to caulk the joints to prevent any air cracks, or put down something permeable on top of the joists like tyvek.

 

[Danno1]

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It's not a house w people living in it breathing, showering, and cooking. Moisture shouldn't be much of a problem. I'd go w unfaced glass batts. But I'd also wrap the sheathing (and roofing of course) w Tyvek or tar paper under the siding. Also, drywall or plywood inside walls.



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[Iplayfarmer]

The first bit of subfloor has been set in place. It's not screwed down, but I set it up there last night just to check the fit after I had finished nailing the cross blocks in that section.

One step at a time. I'm counting my blessings that I'm finding the little bit of time I can to work on this project.