# Need advice on a rural cabin insulation project - new construction.



## imautoparts (Oct 10, 2012)

My Son is making me proud and building his own 30' x 30' home using mostly salvaged wood.

The foundation will be similar to a pole barn - large square posts at a 48" depth with concrete poured around them. He chose the number of posts with the help of an Amish builder friend - I don't know how many but it sure looks like plenty.

He has sufficient metal saved to plan exterior walls of pole-barn steel, hung on 2x4 framing with crosspieces to secure the metal well (we live in a windy area). The studs will be 16" on center apart. He does not have sufficient means to buy exterior wall sheathing for under the metal. Interior walls will be drywall over studs. 

Now for my questions:

1. How do you recommend we plastic wrap this type of exterior wall? Where should it be placed? Directly under the metal? Under the lath cross pieces? Somewhere else?

2. Since the floor will be floating off the ground on posts, how much clearance do you recommend for the crawlspace? How would you seal the skirt of the building to reduce heat loss?

3. What type of insulation material do you recommend that might be widely available as surplus or teardown scrap? Are the R-value gains possible with spray-in foam worth the cost and hassle? Any tips on how to keep the interior walls warm with exterior steel?

Sorry for such general questions - but the kid has a great start and I want to help him every way I can.

John, Indiana, USA


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## md2lgyk (Jan 6, 2009)

It would certainly help to know where this "rural cabin" is located.


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## imautoparts (Oct 10, 2012)

Paulding County, Ohio (NW Ohio).

Our temperatures aren't as mild as Indianapolis, but not as severe as Chicago.


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## jklingel (Dec 21, 2008)

imautoparts said:


> Now for my questions:
> 
> 1. How do you recommend we plastic wrap this type of exterior wall? •• I would not put up any poly in NE Ohio, but I'd put on a layer of Tyvek on the outside, under furring strips, which are under the steel. That will give you a rain screen should the steel leak. Use the airtight drywall approach (Google it) on the drywall, and use air tight elect receptacles, seal any gaps, cracks, etc.
> 
> ...


 •• See after the bullets, above. BTW: nice name. john


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## imautoparts (Oct 10, 2012)

*Moving this Post over from Construction - Need advice on New Home based on Pole Barn*


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## imautoparts (Oct 10, 2012)

OK - Just found 70 bags of cellulose that was leftover from a job and paid $2 a bag for it. :thumbup:

So - blown in cellulose thru-drywall for the walls,

Tyvek for house wrap, over studs, under lath,

Spray poly foam for corners, cracks and window/door edges

Still need advice as far as the crawlspace - recommendations on inexpensive method to either insulate the floor or ideas on how to skirt the house effectively even though the foundation is on posts OR

Perhaps we shouldn't do a crawlspace.... thoughts? We could always plumb the house from the attic.... but I hate the thought of a leak up there in 20 years.

House will be on a woodburner for the first few years, so I don't know how we would warm the crawlspace without big losses. thoughts?

Anyone know how much per sq ft Roxul should cost? Any ideas on where to find leftover or scrap or salvage Roxul type material in the Midwest?

Any ideas of any kind are VERY welcome. Thanks!


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## joecaption (Nov 30, 2011)

What size are those post sticking out of the ground?
Is that what he plans on using to hold up the floor?
Was there any permits pulled to build this like that?
Where's the center supports?


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## imautoparts (Oct 10, 2012)

joecaption said:


> What size are those post sticking out of the ground?
> Is that what he plans on using to hold up the floor?
> Was there any permits pulled to build this like that?
> Where's the center supports?


 
The home is Paulding County, Ohio; and this is a common construction method for rural homes. I'm not sure of the exact number of posts, but looking at his first two rows I'm assuming there will be 16 of them. The house is 30' X 30'.

They are 48" deep, the holes are approx 20" in diameter and concrete is poured in to about an 18" depth, then the remainder is filled with tamped earth. I believe they are 8x8 or 10x10 treated timbers, which have been slathered with tar on the part that is below ground. This is a common method of construction here. - the nice thing about using treated lumber piers is the ability to adjust the floor joists later if settlement occurs. Since this land is inNW Ohio, it was all once part of the "Great Black Swamp". 

The home is on farm land, and local code allows this construction technique. My brother in law has a nice modern home in the same zip code of about 1700 sq ft; it is a two story, and yes, it is on the same type of foundation. 

Here is an example:









What type of "center support" do you mean? 

If you want to learn more about wood foundations, here is a great link: http://www.apawood.org/level_b.cfm?content=app_rfl_cs_about


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## beenthere (Oct 11, 2008)

Thread moved to Insulation forum.


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## imautoparts (Oct 10, 2012)

Update: Just came home from buying 70+ 25LB bags of cellulose insulation from an old farmer a few miles away. Price was $120. I'm calculating the SF now but it is a HUGE pile of bags....  They are old and a bit tore up, so we'll take some barrels with us when we make the pickup. Turns out a local hardware store will loan the blower equipment for free if we buy a few more bags from them. 

Next we need to learn about the best and most cost effective technique for insulating and sealing the floor.

Anybody have a good idea or two?


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## beenthere (Oct 11, 2008)

Spray foam would be the best for the walls. As it will provide your vapor barrier.


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## jklingel (Dec 21, 2008)

$2/bag? You outta bea arrested for stealing like that. Ship me any leftovers. Thanks.


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## imautoparts (Oct 10, 2012)

beenthere said:


> Spray foam would be the best for the walls. As it will provide your vapor barrier.


 
Can't afford it - cost is $3000 just for materials (including ceiling). We'll be using it at corners and around openings of course, but old-style cellulose will have to do; since now we've got two pallets of the stuff!

Can we carefully use heavy poly instead of genuine Tyvek for the wall vapor barrier if we carefully seal the seams? One of my sons-in-law works at a tape factory, so we can get tape at a huge discount. I suppose I should visit the Tyvek website to learn the differences.

Still looking for advice on insulating the crawlspace/floor.


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## jklingel (Dec 21, 2008)

Tyvek is vapor open, w/ a perm rating of about 40. Poly (visqueen) is vapor closed, with a perm rating of about 0.6. People are shying away from poly in all but the coldest climates because it will not let vapor through. That is problematic in cases where you have solar vapor drive (from the outside) and it hits the cool poly; condensation. An outfit in southern Ohio went belly up because of that several years ago. http://www.greenbuildingadvisor.com/blogs/dept/musings/when-sunshine-drives-moisture-walls For the floor, if you install rigid foam across the bottoms of the joists, taped and goo'd edges and seams, and can then dense pack cellulose from the top somehow, you'd probably be fine, imo. Otherwise, get Roxul batts in there, then the foam. The floor joist edges need to be covered. I'd also suggest searching on buildingscience.com and/or greenbuildingadvisor.com.


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## imautoparts (Oct 10, 2012)

I found a tyvek equivalent called tydol at our local home store (Menard's) for $107 for a 9'X100' roll. At those prices we can afford it for the walls.

For the floor, a very knowledgeable guy working in the insulation department said he built his own home using lumber uprights for the foundation, just like ours. He has a crawlspace - sounds like a very similar build.

He recommended a 12" thick 24X48 batts of fiberglass insulation with the paper side down between each joist, edge-stapled and held in place with lath strips every couple of feet. Thoughts? Cost would be about $350


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## beenthere (Oct 11, 2008)

Are you sealing the crawlspace.


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## imautoparts (Oct 10, 2012)

beenthere said:


> Are you sealing the crawlspace.


Not initially. This year it will look like this:










UPDATE: OMG - look at that siding. To clarify, our Foundation will look like this. Our siding will quite frankly, look like a pole barn.


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## jklingel (Dec 21, 2008)

imautoparts said:


> He recommended a .... Thoughts?


 You can either insulate the floor according to building science or a salesman. One is cheap, one is right.


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## imautoparts (Oct 10, 2012)

jklingel, What do you recommend, specifically? 

Spray foam is way beyond budget - I was attracted to the fiberglass batts both by the home store guy's recommendation (he isn't on commission, and they sell all types of insulation products) and by the high r-values claimed on the product literature.

Roxul has been mentioned, but that seems to me to be very similar to fiberglass, but instead is made of rock wool. Is there a significant difference between rock wool (Roxul) and pink-stuff style fiberglass other than the less-itchy installation?

I'm just trying to learn here -


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## jklingel (Dec 21, 2008)

From a previous post: " For the floor, if you install rigid foam across the bottoms of the joists, taped and goo'd edges and seams, and can then dense pack cellulose from the top somehow, you'd probably be fine, imo. Otherwise, get Roxul batts in there, then the foam. The floor joist edges need to be covered. I'd also suggest searching on buildingscience.com and/or greenbuildingadvisor.com." There is a significant difference between FG batts and Roxul. FG batts, unless covered w/ cellulose or in some other fashion, are too porous to air, which moves through and robs heat. Roxul is more dense and not as sensitive to that, and it is more uniform. Roxul will also not rain glass into your body as you install it overhead, and is less sensitive to dampness. It fits better, too. If you use FG batts, you'd likely be ok if you cover the bottoms of the joists w/ foam, sealed.


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## Gary in WA (Mar 11, 2009)

So who pays for the County Auditor or the township/village contact links in #1 and #2 if no building permit is required? 
Or maybe this is in the wrong State; http://www.pauldingcountyengineer.com/resources.htm#township
I've been wrong before...

Gary


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## imautoparts (Oct 10, 2012)

GBR in WA said:


> So who pays for the County Auditor or the township/village contact links in #1 and #2 if no building permit is required?
> Or maybe this is in the wrong State; http://www.pauldingcountyengineer.com/resources.htm#township
> I've been wrong before...
> 
> Gary


That's the right county. Due to the low-lying nature of this part of Ohio, they require quite strict permitting before beginning construction as much of the county is low enough to flood; and due to the sensitive nature of the watershed they are strict about installation of and approval of septic systems. Where they are lenient is in construction methods and standards for owner-built structures.


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