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guitar bell
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# Posted: 4 Oct 2016 06:33pm
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Last year, my husband and I bought a 1940s cabin on piers in Sullivan County, NY for part time use, including in winter. It was previously used as a seasonal but we've added heat and will be insulating the ceiling and want to skirt and somehow insulate the floors. The height beneath the cabin ranges from 12-24 inches roughly. We've gotten some advice to spray closed cell foam on the entire bottom and then skirt it. (Much of the pex is inside the house but there's a small stretch this is underneath). We will be having a simple compressor installed to empty the pipes when we leave in winter. We're nervous about the spray foam because we don't want it to harbor insects and mold and the idea of enclosing the pex in this sounds sketchy in case there's a burst or something. Does anyone have advice to offer? I've read a lot on here about skirting, insulated skating, and the like. Do you think we can use insulated skirting around the bottom and NOT insulate the floors? Maybe put a heat source down below where some of the pex is? We know we'd want to ventilate the area in summer so we'll have the ability to open up vents on the skirting.
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rockies
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# Posted: 4 Oct 2016 08:26pm
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Most spray foams are flammable and can give off toxic gasses when burned and must be covered in a fireproof (or resistant) covering like gypsum wallboard or sheathing. You could attach rigid foam to the underside of the cabin floor and seal and tape all seams but that would also need to be covered. The foam could build a box around the pex on the exterior.
Insulated skirting will turn the underside of your cabin into basically an unventilated crawlspace suitable for growing mushrooms and mold. The moisture from the ground will be trapped and rot out your floors.
The best solution (and most expensive unless you do some of the work yourself) is to take up the floors and have the floor cavities spray foamed. This will create an insulation and vapor barrier in one and allow you to move all the pex into the interior warm part of the cabin.
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hueyjazz
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# Posted: 4 Oct 2016 09:21pm
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Insulation only slows a change and the area below cabin will reach a equilibrium between heated and non-heated sections dependent on the delta between the two and exterior environment. Those Adirondack winters get mighty cold. Any Pex could freeze that's exposed underneath no matter what you do to insulate so maybe use heat tape on that. Don't forget drain lines and interior traps when not heating. Those will freeze too .
Cheap and dirty seasonal solution is bales of hay around perimeter. Not pretty but works
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Steve_S
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# Posted: 5 Oct 2016 08:13am
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The current offerings in spray foam are nothing like their predecessors. They are neutral when cured and do not harbour insects in general. Some older foams indeed did do so thanks to the formula's used... this applied to Spray & Rigid foams... I have some ancient blue foam that Termites love but not the new stuff ! Off-gassing while curing is normal and depending on type of foam (soya vs petro) it only lasts a few hours pending on temps & humidity.
Having used foams (spray & rigid) for nearly 30 years in my various homes & projects, I have had good & bad experiences and seen how the products have evolved.
Commercial Spray foams 99% of the time have insecticidal properties and as closed cell will not absorb / retain moisture. NOTE that they do make an effective Vapour Barrier and therefore that "must be considered when using it" and dealing with natural humidity and water management (if so located).
My climate is not that different from Upstate NY as I am in Eastern Ontario just above you by a couple of hundred miles, therefore the similarities are close enough...
Skirting CAN be a problem if not done correctly and relative to your structure & surrounding grade... Moisture under a house (crawl space etc) is the evil that has to be fought... The arguments over Vented or Conditioned crawl spaces has been beaten to death and as we all knew, vented spaces are BAD ! The Vented will effectively create a "Perfect Environment" for moulds & mildews while providing home to bugs / critters.
Conditioned means you are blocking moisture / humidity from entry to the area and a break from Radon and other gasses as well... There is a LOT of detailed & technical details available but here are two readable articles that help explain such.
http://www.energyvanguard.com/blog-building-science-hers-bpi/an-unexpected-benefit-of -encapsulating-a-crawl-space
http://bloomcrawlspaceservices.com/encapsulation-vs-vapor-barrier/
http://energy.gov/sites/prod/files/2015/10/f27/ba-case-study-crawl-space-whole-house- ventilation.pdf
http://www.nrcan.gc.ca/energy/efficiency/housing/home-improvements/keeping-the-heat-i n/basement-insulation/15639
There are any possible options and relative costs... It all depends on your budget and what your longer term intensions are. Other factors that would modify potential solutions is how is the structure supported, what is the ground surface under, dirt/gravel/concrete, can it be covered over with plastic and topped with gravel (vapour/moisture & gas control). Without knowing more details it would be very hard to offer further advice / suggestions.
PEX: Draining the lines when you leave is best, you can use a small air compressor to blow them out... There is likely drains installed as this has been used seasonally per your description. If possible relocate the "external pex" to inside the conditioned areas (heated / cooled). * If you are conditioning (heating & venting) your crawl space this becomes less of a problem.
Drainage & Critters:
Make sure you divert any water away from the skirting / crawl space using swales to carry it away, direct rainwater away and make sure the gutter spouts are clear and also direct away.
Wire Screening / mesh can keep most small critters out and using products like Hardi-board / Cement board can be to your advantage... Of course it really depends on your approach & what you want as an end result. Keep in mind that many critters will tunnel under sides to find shelter.... Mice are especially good at finding the smallest of holes to squeeze through. Squirrels can and will chew through things... miserable critters...
HAY ? ! That is Critter food and more combustible... Clean Straw Bales offers little food and is less combustible. Can be presoaked with Borax (anti-pest / fungal) & Alum (as a neutral fire retardant) if you want but if just over winter, no worries...
As with all things on the Internet, apply a pinch of salt to all comments (including mine) and read / research. Consider Rational & Logical discussion points and solutions as a guide to help you get the info you need. Look at Credible & Verifiable sources of info such as Government Sites, Building Science & Engineering sites. Both the US & Canadian Governments have made a lot of valuable information available and it is all credible (watch DATES as some updates supersede previous articles). Beware of Marketing, Sales & Commercial business sites as they are selling "their product" and will stomp on alternatives...
Last Point, if someone tells you to do something a certain way and offers no supporting information consider it dubious until you can verify it for yourself... You are your own keeper and must watch out for yourself... Mistakes during building, renovation, etc can be a long term painful and expensive experience and it is worth taking a little extra time to be aware and understand what you are undertaking and the difference relative to your particular situation. Often solutions that work in one climate environment will not work in another due to the general conditions.
Hope it helps
Good Luck
Steve
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bldginsp
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# Posted: 5 Oct 2016 08:53am
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Quoting: rockies Insulated skirting will turn the underside of your cabin into basically an unventilated crawlspace suitable for growing mushrooms and mold. The moisture from the ground will be trapped and rot out your floors.
I agree 100%. The underfloor area needs to be ventilated always, not just in summer. The closed-cell spray foam they have now will not foster mold or insects. I think it's your best way to go, because mice won't get into it like they will with fiberglass. I would not be concerned with the Pex embedded in the foam, so long as no joints are embedded, just lengths of pipe. Pex leaks at the joints, because polyethylene cannot be glued. The compression joints they have work well- most of the time- but I would want access to all the joints to be able to check on them.
For skirting around piers I have used metal roofing buried a few inches into the dirt below. It's a lot of work to install, but provides a positive barrier to keep critters out. The metal will eventually corrode, but not as quickly as wood put on the dirt, and it can be replaced.
Good luck!
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old243
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# Posted: 5 Oct 2016 09:07am
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At our hunt camp, we had a plywood floor that was not insulated. We strapped the existing floor and and added 2 inch rigid foam sheets, between. Then added another plywood floor over this. Quite happy with it. You give up a couple of inches of room height , but get used to it. In our area of Ontario, a big problem with a crawl space is porkupines they like the shelter and will chew a plywood floor, eventually gaining access to the camp. We sheeted the underside with used roofing steel. Good Luck old243
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guitar bell
Member
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# Posted: 5 Oct 2016 12:08pm
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Thanks for your reply!
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guitar bell
Member
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# Posted: 5 Oct 2016 12:11pm
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This was so helpful. Thank you!
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KinAlberta
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# Posted: 5 Oct 2016 08:05pm
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Can you run the pex up and over instead of down and under?
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