Plank subfloor?

[nysharps]

Greetings, I'm new to the forum. We're building a new house and trying to make it as healthy as possible by avoiding materials that outgas harmful substances. One of the big ones is formaldehyde, which is outgassed by most types of engineered wood products. Right now I'm thinking about materials for subfloor. Something like DragonBoard would be ideal, but it's somewhat cost-prohibitive (4x times the cost of OSB or plywood subfloor in my area). Another clean option that is very cheap (minus labor, which I'm going to be putting in myself) is doing it the very old-fashioned way and making the subfloor out of individual planks. The cost of materials is equivalent to OSB, maybe even a little cheaper because I can get the wood at a local lumber mill. Is there a reason why this would be a terrible idea, other than the amount of labor? I'm probably missing something obvious and this is a stupid question... I would appreciate it if you play nice

(Note: I'm not after making the house "green" or scoring LEED points. I'm after removing toxic chemicals. If it means I have to make the floor joists out of whale bone and make the subfloor out of hammered panda leather, we can do that too! )

 

[FloorMaven]

Is there a reason why this would be a terrible idea, other than the amount of labor? I'm probably missing something obvious and this is a stupid question...

(Note: I'm not after making the house "green" or scoring LEED points. I'm after removing toxic chemicals. If it means I have to make the floor joists out of whale bone and make the subfloor out of hammered panda leather, we can do that too! )

it's certainly not a terrible idea...I'm guessing your finished flooring will be a solid hardwood?

I'm thinking hunting whales and pandas would be a bad idea.

 

[nysharps]

I'm thinking hunting whales and pandas would be a bad idea.

You're right, the whale bones might contain unsafe levels of mercury...
Is there anything I should know/keep in mind when doing this kind of subfloor?

 

[Ernesto]

I agree, it's an old method and certainly doable. You should run it at a 45 degree angle. Then you can run the wood either direction.

Be sure to buy kiln dried wood at the correct moisture content, well should be 2 to 4% within the hardwoods MC depending if your doing strip or plank.

Sounds like a fun project.

 

[nysharps]

Another question: I'm using ICFs for the walls with Watkins hangers (http://watkinshanger.com/) to hang the floor joists. The Watkins hanger does not use a ledger board, you can see this in a couple of the picture on the website. How would I fasten the planking at the edges? Seems like a ledger board would be mandatory for this...

 

[FloorMaven]

Seems like a ledger board would be mandatory for this...

You're mixing new and old technology...the subfloor you're choosing needs support around the perimeter Most likely you'll need to install blocking between the floor joists. Are you gonna tell me ICF's have no off gassing? Probably should check with your architect to determine your best options.

 

[DarisMulkin]

I agree, it's an old method and certainly doable. You should run it at a 45 degree angle. Then you can run the wood either direction.

Be sure to buy kiln dried wood at the correct moisture content, well should be 2 to 4% within the hardwoods MC depending if your doing strip or plank.

Sounds like a fun project.

My house was built in the 50's, I wonder if they did moisture tests on the wood when they installed the planking and hardwood.

Daris

 

[Ernesto]

My house was built in the 50's, I wonder if they did moisture tests on the wood when they installed the planking and hardwood.

Daris

Glad you asked that Daris, I happen to have a link for ya. They had moisture meters before that. And then....

An instrument designed to measure the moisture content of material moving along a
conveyor chain and to mark or eject automatically material of improper moisture content
became available about 1950.

Link: http://www.fpl.fs.fed.us/documnts/fplrn/fplrn008.pdf

 

[nysharps]

You're mixing new and old technology...the subfloor you're choosing needs support around the perimeter Most likely you'll need to install blocking between the floor joists. Are you gonna tell me ICF's have no off gassing? Probably should check with your architect to determine your best options.

ICFs do outgas. They outgas pentane, which is much less toxic than formaldehyde and has no long-term health effects. I did my reading (it helps that I'm a biologist too)

I figured out the ledger board problem: I would just screw dimensional lumber to the webs in the ICF between the joists and along each side.

 

[FloorMaven]

I did my reading (it helps that I'm a biologist too)

Then you realize all wood contains formaldehyde as it is occurs naturally. Pentane doesn't sound like any fun...just my opinion but I think you're splitting hairs here.

 

[nysharps]

As respectfully as possible:

1. The amount of formaldehyde contained in a house full of solid wood naturally is orders of magnitude below what is found in even one sheet of regular plywood.
2. Pentane is also a naturally occuring gas. Which doesn't really matter, because gravity is all-natural too but will kill you pretty dead if you jump off a cliff
3. ICFs outgas very little. A natural gas stove in the house would expose you to much more pentane than the outgassing of the walls.
4. Formaldehyde is much, much more toxic than pentane. Look up the MSDSs if you don't believe me.
5. Formaldehyde is much, much more biologicaly active than pentane which means a much greater risk of cancer.
6. If I'm exposing myself to all that pentane anyway (because of building with ICFs), isn't it smarter to minimize my exposure to other harmful stuff such as formaldehyde? If I drink heavily, does that mean I might as well take up smoking and a cocaine habit?

So it's not hair-splitting to me: simply, the benefit of ICF outweighs the risk of pentane, and the risk of formaldehyde outweighs the benefit of engineered wood. Please don't take offense, I intended this as an honest, complete and slightly humorous answer to your question.

 

[FloorMaven]

If I drink heavily, does that mean I might as well take up smoking and a cocaine habit? ...

So it's not hair-splitting to me: simply, the benefit of ICF outweighs the risk of pentane, and the risk of formaldehyde outweighs the benefit of engineered wood. Please don't take offense...

No offense taken, I'm far beyond being offended by Internet postings.

You're talking about risk for the general population but in reality none of us truly knows what type of exposure will be each of our respective downfall. I could be fine with formaldehyde and pentane but I could die from using my Bluetooth headset or the off gassing of bromide from my car upholstery. It is splitting hairs to me cause if I worried about it I'd probably die of worry.