New wood floor for old barn

[quicksandfarmer]

I have an old dairy barn that is roughly 150 years old. It's three levels, with a cellar and a hay loft. The floor on the main level has become dangerously rotten and I've started tearing it out. I'm trying to decide what to replace it with. I'm going to use it as a workshop, so I want a nice smooth floor. I'll probably paint it. The existing floor is 2" rough lumber. I'm mulling a few different options:

I can get rough lumber from a local mill. It would cost me about $1.30/square foot for 2". This would be the historically correct way to proceed (it's possible this is the mill the original lumber for the barn came from). The problem with this is it wouldn't make a very good floor. It's rough surfaced, and even if I sanded it would be hard to sweep. It would expand and contract with the seasons, making cracks for debris to fall in.

I can get tongue and groove modern 2x6's. They're about $2.20 square foot. I think they would make a somewhat better floor than rough lumber.

I could also use sheet goods. The joists are on 21" centers, which means I would probably cut every sheet down to 84 inches, which means a lot of cutting and about 15% waste. An advantage of boards is there would only be 3" waste on a 16' board. I am a little worried that 21" might be a long way for a 3/4" sheet to span.

I could get BC sanded plywood (3/4) for $1.30/ square foot. Tongue and groove plywood ("DryPly" from Home Depot) is $1.32. T&G OSB is $0.54 and plain OSB is $.45.

I'm intrigued by Advantech, which is about the same cost as plywood ($1.32) but I've never used it. Will paint stick to it?

Anybody have any thoughts?

Thanks.

 

[s219]

If using 3/4" plywood on 21" spacing for a shop floor, I'd probably want to double layer it, with the top layer run across the direction of the first. Not sure how that will work out with waste in the case of oddball spacing, but it's not as critical for the second layer.

I had an exposed 3/4" sanded T&G plywood floor in the small barn at my old house, and it took a lot of abuse over the 12 years I used it. I dragged equipment over it, and drove a tractor in and out regularly.

Advantech's main purpose is to survive getting wet for months while a home is under construction. It does that well. If being installed under an existing dried-in roof, there is no need for it. It will hold paint as well as OSB from what I have seen of overspray when painting baseboard trim in our new home, but no OSB product will be durable as an exposed floor deck, paint or not. As soon as you drag something over it, it will start to flake and tear. As a floor deck, OSB is always generally meant to be covered up.

There might be a cost effective approach to going double layer with OSB on the bottom and 3/4" sanded plywood on top.

Personally, I would go with the 2" rough milled lumber for the rustic look, and just accept that it's going to be a little uneven at times. My dad had a shop with that type of floor, and it wasn't too bad to sweep with a stiff broom (I was the one who swept it most of the time). That floor was T&G, and the worst thing is that it was noisy. Driving a forklift over it was a real creaky experience.

 

[hslogger]

if you say it is possible the mill nearby may have supplied the original rough sawn flooring, I would think it was cut with a circular saw. You should be able to tell by looking at the wood and seeing circular imprint. If you had the rough sawn done by someone with a GOOD band saw, chances are there would be more consistency in your sizing. Either way, I would go for roughsawn.

My horse barn floor is 24 by 36 and never regretted it. Periodically I will replace a board. It is all rough saw douglas fir, some done on bandsaw, some on circular saw. I always broom it with the grain, big coarse broom and it does fine. It really isn't the end of the world. If you want it primo, well, then you gotta have a sealed cement floor. A real key to buying the lumber is the mill operator. Some roughsawn stuff is right on, board for board. On the other hand, you could always rent a sander and go over the top a bit to smooth'er out a bit.

 

[2458n]

If the first floor lasted 150 years I would replace it with the same.

 

[wmonroe]

If it was me I would use the 2" thick boards from the mill.

 

[BHD]

the T&G would feel much more solid, (as the side boards are supporting each other)
and if you want a smooth finish, I would over lay with a sheet product, (plywood) would consider a floor paint or clear finish, to protect the wood, and sweepablity.
and possibly in time even some type of finish floor,

 

[oosik]

As mentioned - I would go with rough cut. I replaced the floor in one of my out-buildings(12 x 18) with rough cut and it has been an excellent choice. Looks good & wears like iron.

 

[quicksandfarmer]

if you say it is possible the mill nearby may have supplied the original rough sawn flooring, I would think it was cut with a circular saw. You should be able to tell by looking at the wood and seeing circular imprint. If you had the rough sawn done by someone with a GOOD band saw, chances are there would be more consistency in your sizing. Either way, I would go for roughsawn.

I can see saw marks on the wood where it is exposed. Some pieces have circular marks, some have parallel marks. I've read that mills in my area went from using pit-style saws with a vertical reciprocating blade to circular saw blades around the time of the Civil War, so I figure the barn must have been built about the time of the changeover. Some beams have one type of mark on one face and another on another. There's no indication that the wood was reused or replaced. According to the tax records the house dates from 1850 and the barn is similar construction.

I've purchased a fair bit of wood from the local mill already for various repairs (I feel like I've done nothing but fix this barn since I bought it nine years ago). The wood has been excellent in terms of its uniformity and very pleasant to work with. It's not nearly as hard or dense as the old-growth wood from 150 years ago though.

 

[quicksandfarmer]

My horse barn floor is 24 by 36 and never regretted it. Periodically I will replace a board.

This is a factor that has me leaning away from tongue and groove. I've done nothing but fix this barn, I can see myself having to take up the odd board for future repairs.

 

[quicksandfarmer]

If the first floor lasted 150 years I would replace it with the same.

I'm aiming for more durability this time. I don't want to burden the great-great-great-great-grandkids!

Sounds like everyone is favoring the rough cut. I thought there'd be some love for the sheet goods but I guess not.