OSB instead of drywall ?

[jimbob44]

Other than material cost, is there any disadvantage to using OSB instead of drywall for walls and ceilings? (The joints could be covered with lath strips or trim molding and all painted with a spackle type paint)

[Bart_Cubbins]

You wouldn't have the same fire rating unless you used a special fire resistant paint, like this stuff...

http://www.contegointernational.com/

[greg273]

 I've noticed OSB tends to off-gas its binders for awhile. I sheeted the inside of my dads pole barn with 7/16 OSB, that was 2 years ago and I can still smell the stuff.
  If you're going to paint it, that may very well seal the OSB well enough.
  

[Lady_Novice]

OSB as wall covering might be okay for a shed or garage, but for a family dwelling I wouldn't use it in place of regular wall covering (such as drywall or real wood paneling of some type), for two reasons:

(1) I've seen it used as wall covering and I didn't think it looked too good, even painted.

(2) It is full of formaldehyde gas, which is toxic to breathe (might not be a problem if used as exterior sheathing, but not good for the interior). Different people have different levels of sensitivity to it, but I know I react poorly to it. I keep wondering when the manufacturers are going to remove formaldehyde from the glues in building products, but it would take more awareness from customers before that happens.

AFM Safecoat sells a clear solution that you can paint onto the OSB that would reduce some of the outgassing, but I conjecture that it could affect the breathability of the wall.

FWIW, OSB rated for EXTERIOR use has less formaldehyde as the glues are different for that purpose. Also, I believe you'd have less exposure to formaldehyde by using plywood instead, as the glue is underneath the top layer. Plus, it may look better. I believe the worst product to use would be particle board; this stuff, as used in cabinets, is the highest in formaldehyde compared to other products.
Lady Novice

[Amanda_931]

It tends to look, well, like painted OSB when it's painted.  Not one of my fave looks.

Might be able to put a thin coat of genuine lime plaster (start hydrated lime soaking as soon as possible--Charmaine Taylor recommends rubbermaid tubs--I think she's probably right, considering how much of a pain olive barrels are.  In fact her websites are a good source of information on the subject www.dirtcheapbuilder.com check out the free stuff)

The gal in the DVD Building with Awareness also does a good job of explaining lime plaster.

Do tests to see what it's going to do-- three to five parts sand to one lime, might be able to go as high as 8 parts sand.  Not sure how you should treat the joints.

[jimbob44]

Now I'm wondering about using blackboard over the studs (2'on center) for rigidity and then thin paneling over the blackboard.
Anyone tried that....

[Lady_Novice]

jimbob,
Is blackboard a type of insulation? (I've heard of blueboard but not blackboard.) By paneling, maybe you mean what I've seen at Home Depot, which looks like a thin veneer of wood paneling over some type of composite material, perhaps. Looks okay.

For me, the best inexpensive wall covering that I've heard about is just gypsum board, which you don't put any work or money into trying to tape and perfect it, because you just paint it and place strips of solid wood or trim or moulding over the seams. I haven't yet tried it or seen it in real life but I plan to use this idea in my cabin.

Amanda, I just happened to see the website for "Building with Awareness" the other day. I remember they said that regular plaster dries quickly so it's difficult to do perfectly, but their plaster recipe is an easier alternative. Sounds interesting.
Lady Novice

[Amanda_931]

Gypsum plaster sets up very very quickly.

Lime plaster gives you time to work.  Easier for those of us who didn't apprentice to a plasterer.  It might be "greener," certainly has a long history of use (the Romans loved it).

I'd recommend the DVD highly if you want to plaster, earthen, lime or gypsum.  The gal who is on it uses a simpler recipes for the earthen plaster than Cedar Rose Guelberth, who wrote the more available book.

Ran into an acquaintance with a lumberyard last night.  He said that he'd been selling (probably that roughly 7/16) OSB for 17/sheet, just got the word that his cost was going to be a couple of bucks more than that.  That there were a bunch of producers out--most for lack of electricity.

And yes, we went through this around the beginning of the current war.

I haven't seen blackboard in years!  If I thought about it at all, I thought they'd stopped making it.

Not structural properties--like ceiling tile--and black.  What we used away from the corners when we braced the corners with let in 1x4 or plywood.

[stricsm]

An easier way to finish drywall for a stucco look is to mud and paint at the same time (easier in the sense that no sanding is involved).  Use lightweight drywall spackling compound and mix paint in.  Apply to drywall with a trowel and finish with a mesh roller for a suttle stucco look.  For a more pronounced look, don't roll but use crumpled plastic bags.  Wally World bags (inside out or the ink bleeds) work great.  This can give you a heavy stucco look if you trowel on thick.  Measure paint and spackling to keep the color consisent.  I usually prepare in 2 gallon batches.  A gallon of paint goes a long way.

[jraabe]

Interesting technique Stricsm!

Do you find the wall surface seals up enough to not collect dirt or do you need to go back with a second coat of paint?

[stricsm]

I've used this technique with dark yellow and with light green paints.  Both require only one coat if you trowel on heavy and use the bagging technique.  Rolling may require two coats.  I started rolling but the texture wasn't pronounced enough for my wife, so I switched to bagging.  I did our bathroom in yellow over a year ago and it has held up well.  A friend taught me how to do this on stucco/lath in lieu of repairing stucco.  Our church is all lath and stucco.

An added benefit of this technique is that it cost much less than textured/sand paint.  I've done several rooms using sand paint which is difficult to apply properly.

[Lady_Novice]

stricsm,
That does indeed sound interesting. I might want to try it on a few of my future walls. I like texture and had seen some textured paints at a big box store but your technique sounds like it's better and saves money.

Does the paint change color, though, with the addition of the white drywall compound? Like if you start with a muted blue-gray paint, would the paint turn a whiter, lighter color? (Paint colors are so tricky, it seems. I once chose what I thought was a sandy, muted peachy-beige color and ended up with a pink wall.)
LN

[stricsm]

Yes the final wall color is different from the paint color.  Buy paint two shades darker than you want the final walls to be.  Experiment with the mixture by applying it to a scrap piece of sheetrock and letting it dry.