OSB

Model Railroader Layouts and layout building
1

Tried to post this earlier from my phone…but it didn’t work

Has anyone used 5/8" OSB for a table top instead of plywood? In my area the 5/8" OSB is about half the cost of 1/2" B/C plywood My plan is to paint the entire to surface flat brown to seal it before I put it on the framework

Thoughts or comments?

Thanks in advance, Paul

2

To me, OSB seems reminiscent of particle board, which has many undesirable characteristics. Particle board is very heavy for its size, has a tendency to warp if not heavily supported and/or coated with a sealant, reacts badly with moisture, and is difficult to cut, nail, or drill. (I am also told particle board is very hard on saw blades and drill bits.) Even if OSB is less prone to warp or disintegrate in moist conditions, I would still be concerned about its weight, and workability.

Having said all that, I’ve never used OSB, and the next time I build, I’ll probably be looking to use plywood or foam board.

3

I have used it, and been very happy with it. It is very stable and moisture-resistant. I even made a rabbit hutch out of it, which has now been outside in all weathers for six years, and is fine in spite of being unpainted or otherwise protected.

According to Wikipedia: “OSB panels have no internal gaps or voids, and are water-resistant, although they do require additional membranes to achieve impermeability to water and are not recommended for exterior use. The finished product has similar properties to plywood, but is uniform and cheaper.”

I recommend it.

Justin

4

My earlier reply didn’t post.

Are you building a flat top table?

Or are you using the OSB as a plywood replacement in the one of the following ways?

  • cookie cutter layout where plywood is cut along track edge and elevated to give different track levels
  • cut into long (possibly curved) pieces for subroadbed
  • cut into strips and used as substitute for 1x lumber in building frame

OSB produces nasty splinters and chips when sawn, and is hard on blades. OSB cannot be sanded to a smooth finish. OSB is tougher to nail into than plywood because of many more glue hard spots. OSB is designed as a cheap but structurally sound sheathing for construction that will be covered by some other material.

Because of its characteristics, I would only use OSB as a surface for a flat table where it is going to be covered over. But that’s my opinion.

You compared OSB to BC plywood. I would not recommend BC plywood for anything other than the flat table either. Today’s BC plywood has too many voids that get exposed when the sheet is cut. With a void on an exposed edge, the plies tend to collapse at the void, or warp because of the loss of strength at the void.

IMHO, to use in cookie cutter mode, ribbon subroadbed, or as a replacement for 1x lumber takes AB grade plywood or better.

just my opinions and experiences

Fred W

5

I have found that the OSB when cut after a couple years tends to become weak. Especially when cut into cookie cutter form. I am currently replacing the OSB with Plywood as I change sections of the layout. Had it to do over I would spend the extra bucks for Ply.

**I have used in full sheet form for a table and covered with carpet for a work bench. Works great there.

6

I am going to use it in area thats approx 2X8’ where it will be flat table top

7

dbduck

I have used 7/16" OSB for all but a few special places on my 2000 sq ft layout!

I have no problems with it - BUT - I paint the surface!

Also when I use large flat sheets I support the underside on 16" centers (or closer) as OSB was NOT designed to be laid flat and support long spans!

As for nailing into OSB - I don’t!

I cover all track areas with Homasote and glue it to the OSB!

The OSB is drywall screwed to the 1x2 supporting joists.

While a lot of modelers state that 1x2 dimensional lumber is too small to use for benchwork I can stand on my benchwork and I am on the high side of 250 lbs!

I have found that the OSB is much more stable in a varying humidity situations than the 1x2 dimensional lumber I use for the L-girders and cross joists!

Again YMMV

BOB H - Clarion, PA

8

OSB was designed by the building industry as a cheaper alternative for plywood subflooring or wall panels.

Because of its construction, it is more rigid and less susceptible to warping over short distances. It would serve very well as a cheap alternative to plywood for a tabletop, but it is designed to be used in large sheets with close interval support (16 - 24"). Both because of it’s tendency to splinter when cut and the fact that thin pieces may not have the same structural strength as the whole sheet, I would recommend against it’s use in thin strips for subroadbed or other construction.

9

CTValleyRR

I have to take exception to your statement

" I would recommend against it’s use in thin strips for subroadbed or other construction."

I have built benchwork down to 2" width and also 4" - 6" & 8" width.

I have had no problems with cutting the 7/16" OSB down to these widths and have not run into excessive splintering (have to use a sharp blade - which does not last long)!

I have over 2000 sq ft of layout with 4 levels in some places and the layout has 90% use of OSB subroadbed!

The layout was started in 2001 and now that it is 10 years old - the OSB subroadbed is in as good condition as the day I build the benchwork sections.

One just has to be a bit more careful when designing the 1x2 framework when working with OSB.

Although I do have some places that I have used 11 ply plywood for ultra thin benchwork and I had to engineer special supports for this type of super thin (1" thick) benchwork.

This Thin Edge benchwork was designed to open up the sight distances between the multi-decks on my current layout.

BOB H - Clarion, PA

10

Bob –

I think the reason you’re not having trouble is that you’re not really supporting much weight with the OSB.

I’m glad it works for you. My point is that it’s not intended to be ripped into narrow strips.

11

i thought about using it too. i put a couple sheets in the attic for general storage and when i went back up there after a couple days, it sure did smell. the attic is ventilated. i was concerned about the glue used and if it would have any affect on us being in the basement where the trains are. even if i seal it up, if i go back and drill a hole or modifiy it later, i would have to repaint it to seal it up.

does anyone know if this is safe in regards to the glue and smell??

thanks jay