Fish Shack Floor

My skids for my new house will be delivered this weekend. I am building a 10×20 shack. For my floor I plan on using 2×4 green treat with 1/2 or 5/8 marine grade sheathing and using closed cell spray foam for installation. My question is once a spray foam the bottom do I need to cover it with anything? Not sure how the foam holds up to the elements and bugs. The floor will be built on 4″x6″ steel skids.
Also I was going to spray foam it myself (never used the stuff) or is there a reasonably priced guy or company that does spray foam around Mille Lacs?

You don’t need to cover the foam under the floor. But being a skid house, it wouldn’t be a bad idea. I have an alumalite and the foam is not covered. Has held up well and hasn’t had any bug/animal issues.

Sounds like it will be a heavy sum beach

I have nothing to offer, BUT I miss having a skid house on Milly.????
DT

Besides the skids it will pretty lightweight. Steel studs, spray foam and 1/8″ paneling.

I would reccomend 2×6 floor over 2×4. If you are spending the money on steel build it to last and be sturdy. Also screw everything.

mark-bruzek wrote:

I would reccomend 2×6 floor over 2×4. If you are spending the money on steel build it to last and be sturdy. Also screw everything.

I would agree with having a 2×6 floor over a 2×4 floor. will be more sturdy and last a little longer. I have a 10×20 with 2×6 floor. My house just has the 2″ Styrofoam pieced in and glued I believe (bought the house that way). But mine isn’t covered and I haven’t had any issues in the 11 yrs I’ve had it.

Isn’t that along ways off the ice? With skids, flooring joists and blocking?

I did talk to a couple people and they said with the closed cell spray foam the floor would be rock hard.

Brandon Johnson wrote:

Isn’t that along ways off the ice? With skids, flooring joists and blocking?

Kind of. Its not terrible though. I have 22′ 5×8 rough cut white oak skids. Without blocking its is about a foot off the ice. IMHO, Being a off the ice a bit isn’t a bad thing. When a snowstorm comes and the water starts to come up from the drifting around the house and truck, those extra few inches are worth it!

Brandon Johnson wrote:

I did talk to a couple people and they said with the closed cell spray foam the floor would be rock hard.

It very well may be sturdy enough. I have no experience with the spray foamed floors. Solid or not, skid houses take a beating when being moved around (too the lake, moving spots, off the lake). As most know, ice isn’t very even. At least not on the Big Pond. Lots of flexing going on.

I would suggest 2×6 for the floor. Any exterior sheathing besides the spray foam? Really have to keep steel studs rigid with something. Lots of flex in a house that big. Anything besides the floor tieing the runners together? What kind of treatment are you doing to the marine grade plywood?

I did change and will be using 2×4 wood wall studs 24″oc with spray foam insulation.
The outside will be pole barn siding. The skids does have 3×3 angle iron at the front and back to keep the skids squared along with 4 mounting plates along each side to secure the floor frame to. What do you mean treatment of the marine grade plywood? It will have spray foam underneath and rubber for the flooring.

I recommend putting down some sort of rubber flooring inside of it….

Has anyone ever used 2×6 16 gauge metal studs/joists for the flooring joists? Or any other structural steel floor joists? I know it will cost more but the weight difference is about 200lbs lighter vs ground contact lumber.

16 gauge studs will rust out pretty quickly, they are not an exterior galvanized as far as I know.

2 x 4 will not make it, 2 x 6 does (barely) has to be southern yellow pine and not SPF.
I ran these with treated material. (When lumber is treated it loses some strength.)
also
Make sure it is closed cell foam and not open cell. Closed cell can be structural open cell is not.

https://www.awc.org/codes-standards/calculators-software/spancalc

oops the chart defaulted back, but you can put in your specs.