WOOD GARAGE FLOOR

[DPatton]

I have been working on a "super cooler" for a off grid camp and using leftover pieces of foam board to make a foam box, I taped the box together with regular duct tape and the pieces that I stretched a bit to get some tension on to hold things tight did not stay on the pieces that I did not stretch sort of stayed and the pieces that I went all around the box and returned to tape stayed.

In short the tape did not stick well to the foam but did stick well to itself so far.

The foam box will be covered with a wood box in the end so it won't matter for my application.

Hilltop,
I built one similar to that years ago. It is 4' x 4' x 2'+ tall. I made a plywood box with a 1' x 1' angle iron frame to hold it all together. Placed a 15 mil plastic liner inside of the wood box and snug fit 3" thick blue DOW rigid foam on all sides, bottom and top. Then installed side handles, keyed locks, and a chain stop for the lid. it was built to fit the back of a full sized pickup bed and has worked great for icing down elk, antelope, or hogs for the trip home. It also serves as an nice dry storage box in the back of a pickup. 

[RAYGYVER]

Your right I did think you were showing two 1" layers of wood, my bad.

 However I would suggest against the method you are proposing simply because normal seasonal movement of your floor boards will split each board at your fastening pattern. a board that wide will shrink and or swell significantly with moisture and humidity changes. That's why most wood floors are built using narrower boards.

hmmmmm......I was not factoring in the shrinkage and swelling......
Maybe a narrower board should be spec'd here. The big question is can I make it narrow enough to still fasten using screws? If not, then the next question would be, can I get away with no fasteners? Just let the boards float. At that point, I should just use full 12" wide boards. I may have to vacuum out the seams a couple times a year.....hmmmmm
I should at this point remind myself that this floor isn't going to perform like concrete. So I will need to engineer the negative traits to an acceptable level. Shrinkage being the bigger issue....thats what she said.
 

[rjwoelk]

They have a red construction tape i think it maybe called tuck tape used around windows plywood joints sheet foam joints. Check HD.

[Crusarius]

make is out of 2x4's screw them together in 12" pieces then set them together and let them float.

[RAYGYVER]

make is out of 2x4's screw them together in 12" pieces then set them together and let them float.

That sounds like a lot more work honestly. I might go with 2" thick and 8" wide. Do a 10' x 10' test area and see how it performs.

[Hilltop366]

If the boards are fastened together as one unit and not fastened to anything else would it expand and shrink as a unit and not split at the seams? It certainly would need a expansion gap along the walls.

For fastening the foam together I can remember having trouble doing a floor with the foam moving around and thinking if there was a way to stitch them together with some sort of spring loaded clip that could be spread a bit with a hand tool and then insert one leg from each side of the clip in each sheet of foam. Its pretty hard to have a original thought these days so someone must have come up with something by now.

[D L Bahler]

Could you go with t+g boards, or boards that are dowelled together? That would hold the top surfaces flush, assuming they're milled/joined accurately (or better yet, you just run over the assembled floor with a sander to make it smooth). The only potential problem with this method is if the boards push out with expansion, when they shrink back down small gaps will open up. 

Wider boards will be prone to wider gaps. But that's assuming all things being equal, which they wont be. Most likely one or two joints will gap large instead of the boards coming apart evenly all around. You could of course solve this by having a wedge you can drive in at the edge of the floor to push the boards all back tight. 
 

The thing I'd worry about fastening the boards together is that the friction of the floor surface would tear them apart when they try to contract, splitting the boards where the screws are or just ripping part of the lap off of one of the boards. 

[Brian_Weekley]

I agree that tongue and groove might be better than using fasteners.  The T&G would help keep the boards aligned.  I was also wondering if it would be possible to mill some kind of locking joint similar to Pergo-type floors?  Between the foam and wood, you might need some material to reduce friction to allow them to move easier with expansion/contraction?

[RAYGYVER]

All, thanks for the comments. This is exactly why I put this thread together. I knew you guys would help evolve the project.

T&G would be easy enough on a table saw to create the tongue side, and a router down the groove side. That would solve the top plane issue. It wouldn't pull apart and cause cracks. 

I might be over thinking this whole thing. Just Tongue and Groove the boards, expansion joints at the walls and be done with it. 

I can't wait to get the mill going.

Now, material.....there is a lot of Ash around here....its hard, so I would think Ash would make a good floor board. Any objections?

[D L Bahler]

lots of barns around me with ash floors. hay mows, drive floors, all ash. Bugs will find it eventually though. powder post beetles are fond of it. Wash it down with borax often, that'll keep the bugs and mold at bay

[Crusarius]

you really want to get fancy make a post tension floor. Drill holes all the way through the floor and install cables to keep it tight. In concrete this strengthens the floor alot. I don't think it will strengthen a wood floor but it will hold it tight and cables with stretch with the floor.

I have been trying to find a set of router bits to make a pergo style tongue for a while. If anybody has any suggestions or ways of doing it I would be very interested. I have radiant floor heat in the concrete slab in my house. I want hardwood floors but have no way of fastening them to the concrete. A simple tongue and groove will just pull apart creating gaps.

[Brian_Weekley]

Giving it some more thought, I doubt a Pergo-type connection would work.  Unlike Pergo which is an engineered substrate, solid wood is going to have much greater expansion and contraction.  I just can't imagine that a large floor could float/move enough to keep it from tearing the connections apart--especially if you had heavy items sitting on it.

Crusarius--I want to put in radiant floor heat when I build my retirement house.  I was also wondering if you can put a wood floor on top.  I think if you did use T&G, the boards would have to be narrow to minimize the size of the gaps.  I was thinking it would have to be either really pretty cement or tile with throw rugs on top!

[Hilltop366]

I have a glued down engineered wood floor (about 3" wide) over concrete with in floor heat in my living room. It is made from three layers of wood with alternating wood grain, there has been no problems with gaps from seasonal movement but like any wood floor anywhere there has been a water spill that has sat for a bit (over watered plant, leaky Christmas tree stand) the wood has pushed apart and then dried leaving a slight gap with discoloured edges and lifting of the finish along the edges.

Heat transfer seams slower compared to the tiled sections of the house so it may be advantageous to add a second source of heat to get enough heat in a large room if you live in a area with fast temperature swings.

If I was doing it over again I would be tempted to find a different way to build other than floors directly on concrete.

If building now and wanted a slab I would be looking at using a wood boiler with large thermal storage tank and a wood framed floor over concrete with in floor heat (not in the concrete) plus either radiators or a heat pump. The big advantages with this would be more forgiving floors (softer), the ability to be able to heat up or cool down a room much quicker but still be able to have a even temperature level with comfortable floor temperature. 

[Crusarius]

Crusarius--I want to put in radiant floor heat when I build my retirement house.  I was also wondering if you can put a wood floor on top.  I think if you did use T&G, the boards would have to be narrow to minimize the size of the gaps.  I was thinking it would have to be either really pretty cement or tile with throw rugs on top!

You don't necessarily have to do it in concrete. you can do it on plywood and joists then place hardwood on top. I already have the slab so I am kinda stuck. I never realized how much I like having it till I had it. My shop will be getting it also.

[Crusarius]

Hilltop, that is the hardest thing. Trying to have floor warm enough to heat entire house but not to warm your feet are on fire. I have a wood stove for the volume and use the radiant floor for the contents.

If I was using just the radiant floor I would need to have it quite a bit warmer to keep house warm and then it would not be comfortable for my feet.

[RAYGYVER]

Well, I got the mill put together this afternoon. Runs well. The blade tracks good. I haven't cut anything yet. Its really windy here today and I am beat. I'll try cutting something tomorrow.

Here is a link on calculating wood shrinkage and expansion:

How to Calculate Wood Shrinkage and Expansion | Popular Woodworking Magazine

and another:

Calculating for Wood Movement - FineWoodworking

[RAYGYVER]

Well, I cut my first log this weekend. I had cut down about two months ago a rather tall Honey Locust. So I used it as the experimental first log. The wood was beautifully spalted. I got a nice 10' long by 2 1/4" thick slab, and a 10' long 4 x 6. The trunk wasn't super straight, but straight enough to get those pieces. I'm guessing I am making a live edge coffee table out of the first board I ever cut. 

I think I've been bit by the wood bug....its all I can think about now. 

I've got a pile of Ash logs a buddy found for me, I'll be picking those up this week. I'll probably try to make the first 10' x 10" section of this wood floor out of those.  

[RAYGYVER]

 

 

[Ruffgear]

I think if I were set on using solid wood and having the limited floor height. I would put down my foam, then lay green treated 2x4 flat 16" centers, then use your sawed lumber on that roughly 2" thick and ship lapped.  So you have total height of approximately 4 1/2".  I think you could go much thinner with boards also, depending on what your putting in there.

[RAYGYVER]

I think if I were set on using solid wood and having the limited floor height. I would put down my foam, then lay green treated 2x4 flat 16" centers, then use your sawed lumber on that roughly 2" thick and ship lapped.  So you have total height of approximately 4 1/2".  I think you could go much thinner with boards also, depending on what your putting in there.

Thank you for your input. What is the benefit of the treated 2x4s? If the foam board is my moisture barrier, do I really need treated 2x4s?
I want the wood to be in full contact with the foam. If I lay the 1"-2" thick boards on top of 2x4's then that creates an air gap between the foam and bottom of the floor boards. Full contact with the floor boards spreads the load out. I would be increasing point load on the foam if all the load was put through the wide side of the 2x4s. 16" O.C. treated 2x4 over a 40' x 40' floor increases the cost significantly also.
I like the ship lap idea, basically the same idea I had in the pictures in previous post, just the lap was on the same side in my design. 6, half dozen, or the other. My design would have the drawback of every other board looking wider than the previous. Traditional shiplap would make every board look the same width.

[Ruffgear]

If your confident no moisture will get through or on your foam you may not need green treated. I guess I would treat them as joists on concrete or ground, in my area code would require green. I've seen many people try and get by without, seems to come back and bite em. Currently a project I'm on they put plastic under plates rather than use green, they've all rotted away.
I agree it would increase point load and cost, but you would save by using less lumber.  Getting your dirt perfectly flat can be a chore and this would allow you to float over some of that. Would be similar to how they do gymnasiun floor.

[RAYGYVER]

Ruff,
  I see what you are saying. If I can get 10 years out of the floor before needing to replace some pieces, I'd be good with that. I think I can do better than 10 years though. I don't have any code around here for barn floors. 

[RAYGYVER]

So, I liked the shiplap idea. This thursday I am going to go pick up a bunch of Ash logs from a friend. I'll start milling slabs and start the drying process. I don't have a kiln, so they will be air dried in the barn. Anyway, I have some really old rough sawn lumber I pulled out of a barn in Indiana. I think I'll take the time to make a test area for the barn. I'll compact the soil and gravel, bring in the sand and go get one 4'x8' foam board. I'll make up the shiplap and test out the floor design below in the 3D model. I'll sit my engine stand on it, and put the Impala's 327 on it to see how it settles, if at all. If it survives that, it should survive everything else I throw at it. That is a lot of point load on three little caster wheels.

More importantly, I'll be looking for moisture build-up under the boards. If it stays dry, even when a little moisture has wicked into the gravel below, I'll be pretty confident the foam will suffice as the moisture barrier.



 

[Crusarius]

you may want to use 2" foam instead of 1" will give you a more comfortable temperature in the floor. and take out the bounce a little better. Just in case you do have low spots in the sand.

[Don P]

I'd bag the sand if possible and use #9's to avoid capillary moisture through the fine aggregate. That's why we use clean washed rock under a slab. I'd be aggressive with the casters/engine around the shiplap and see if they break off. The shorter and thicker you can make them the better. I like the gym floor idea, you can use more or total sleeper area out of your ugly wood. IIRC the foam is good for ~10psi, there are 144si's in a sf. Residential loading is 40 psf, commercial 100psf, shop is whatever you need but there probably won't be a tank on it.