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Small Cabin Forum / Cabin Construction / Tell Me This Won't ROT in 5 years!! (help)
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WTFarm Girl
Member
# Posted: 2 Apr 2021 08:24
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Ok, long story short, I ordered an "Amish made shed cabin". It's also 200 sqft

They were hard to come by this year thanks to everyone spending stimulus checks, so I was greatfull to find someone who could not only make me one at a decent price but also in 4 weeks.

Needless to say, I got HOSED.

Not only was it several months late, BUT was NOT made to spec.

The issue I am looking at now (with horror), is the FLOORS ARE ROUGH SAWN PINE!

They were suppossed to be hardwood. Unless this is something that LOOKS like pine? The rest of the cabin is fully green pine that has now dropped to 12% moisture over winter. The floor is also running about 8-12% moisture.

I told the guy before ordering that I would be turning it into a cabin office.

That's what I've been doing, but now I'm looking at what to do about the floors and I am stumped (and scared).

From what I've read, untreated pine WILL ROT in 5 years. The floor is on joists and those are on treated 4x4 posts. I HAD thought I would attach board insulation underneath, until I realized it had joists over the 4x4's. I would have to jack up the cabin and cut a few dozen chunks of insulation and stick them up one by one. Not fun . . . or safe.

Currently it's on a large crushed asphalt pad, but moist air is blowing up through the floor and into my walls, raising the humidity in one particular wall. It WILL BE MOVED in a few months, but not sure the best type of pad for long term?? The cabin will be finished where it's at and then dragged on it's skiis to the new location a few hundred feet away . . . it will be TOO HEAVY to lift

Anyway, ideas on the floor? Will it be ok? I had thought about covering the inside floor with plastic sheeting, then adding board insulation, then thin ply then wood flooring. Will this trap moisture and rot as well? I need a full covering on the floor and insulation.


I live in Michigan, cabin is on my wooded farm, will be on edge of woods.

Also takign suggestions for bug-proofing the outside pine wood and stains/sealers that are long lasting

Bruces
Member
# Posted: 2 Apr 2021 08:44
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If you raise the cabin off the ground on piers the floor will be fine .

WTFarm Girl
Member
# Posted: 2 Apr 2021 08:53
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How far does it need to be raised? It's 4in off the ground right now with the treated 4x4's . . .

FishHog
Member
# Posted: 2 Apr 2021 09:30
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really depends on how much moisture comes up from the ground.
But if it stays dry your floor will out last you.

Atlincabin
Member
# Posted: 2 Apr 2021 10:12
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And put a layer of plastic on the ground underneath the cabin in the new location. Then make sure there is some ventilation between the cabin floor and the plastic. If it's on treated 4x4s, I suggest drilling a few 1" holes in the 4x4s and cover with screen to keep bugs and small critters out. If you put it on piers, I would add the plastic on the ground and also add some skirting board around the bottom, also with some vent holes. That should keep it pretty dry underneath unless you have a lot of sideways rain.

snobdds
Member
# Posted: 2 Apr 2021 10:27
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Hardwood can be any wood that leafs out. How do you know it's not hardwood?

If there is an air gap, the floor will be fine. Any type of prefab unit that is made to be put on the ground, or close to it, should be put on a properly made pad with good drainage. There should be no dirt anywhere near your place. It should all be good road base rock compacted in 4 inch lifts.

gcrank1
Member
# Posted: 2 Apr 2021 11:20 - Edited by: gcrank1
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I think the 'rot' you are worried about is for exposed to the elements, bare wood, etc. Fwiw, Ive got unfinished pine in a lot of my stuff at home and that is decades old with no deterioration with decades to go. I even made an outside deck out of std. untreated left over 2x6 and 8 lumber 20years ago that took 15years to go bad.
Btw, imo I think the joist level above grade should be about 1'. Use good sized cement pads (Ive used rectangular 'silo block' but nice pre-made pads of round or square are available) on the leveled prepped surface and a piece of asphalt shingle between the cement and the treated beam.

hueyjazz
Member
# Posted: 2 Apr 2021 11:47
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I the "English" that lives among the Amish where my property exist in NY. (English is Amish code for outsider)

My Amish are totally into lumber. They either cut it down, saw & mill it or build with it. I very familiar with their construction and have had them build me storage shed about the same size as yours. I did make them put mine on three 8 x 8 and used pressure treated plywood for floor. But I did have the advantage of being there while the 14 of them built it.

I'm not sure I would put plastic down anywhere seeing that you are in Michigan and can expect a good amount of snow. Plastic might trap the moisture and then you will have rot.

I agree with snobdds that a good base of stone that drains is your best course. I would also use geotech fabric under stone. Along with adequate airflow underneath. The most common failure I do see with these sheds is the ground wasn't adequately prepared before the shed placement. And I see a lot of these sheds.

In my experience Amish lumber is always green and you should expect shrinkage. I assume the construction is board and batten that tolerates some shrinkage.
Also board and batten is far from air tight or mouse proof. I used Ready-Seal stain on mine and it's on it's 7th year. It still looks good but I plan to stain again this summer. No stain is permanent

Brettny
Member
# Posted: 2 Apr 2021 13:59
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Your shed will be fine. Raise it up on concrete blocks. Stain it with an oil based stain this summer. Get one from a log home industry based company not a big box store. Expect to spend about $200 for 5gallons.

Brettny
Member
# Posted: 2 Apr 2021 14:28
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Quoting: hueyjazz
I'm not sure I would put plastic down anywhere seeing that you are in Michigan and can expect a good amount of snow. Plastic might trap the moisture and then you will have rot.

I'm thinking the same thing. Moisture can come up from the ground or down from the sky so I think just raising it up is best.

Also it being on 4x4 runners and those being on the ground means that your shed is on the ground. Those runners are a key structural part of the shed, protect them as such.

toyota_mdt_tech
Member
# Posted: 2 Apr 2021 20:10
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How about a breathable barrier such as a tyveck under the flooring, not on the ground. With it low to the ground, could you staple it on one side, pull tight and staple up other side?

WTFarm Girl
Member
# Posted: 3 Apr 2021 06:01
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All good thoughts!

The floorboards looks identical to the ones used in the loft which are most definitely pine (I nearly got stuck up there with the sap).

The outside walls are shiplap, overlapped at barely 1/4" so they are pretty much just barely touching each other now that they are dry. Sprayfoam has eliminated any bug gaps, and wood is at 10% moisture on the outside.

I had wondered about possible doing plastic under the gravel base.

I'm not familair with Tyvek . . . if it's breathable, won't it let moisture air up?

Brettny
Member
# Posted: 3 Apr 2021 06:10
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You dont want to seal this building up right away. There was one member that did something of the sort and things started to mold.

Tyvex is basically a one way valve for moisture. If your useing bat insulation under floor I would use it. I suggest you jack the building up and use foam board between the floor joists, then caned spray foam around all the edges of the foam board. This method is called "cut and cobble".

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