Fact sheet: Birch Plywood
Background:

Again, many out there asked me info about what plywood to use...I only used birch plywood for the moment with good to perfect results...
Birch plywood is mostly sold in 1m 52.4cm by 1m 52.4cm (or 5 by 5 foot panels)...
Most of them are made up from Baltic Birch...one side has a perfect finish, the other side is patched up...

First:

So...try to find this type of wood...big suppliers normally have it...I got hold of some that was very cheap but found out that it was of the BB/BB type...this means patched up on both sides...not a real problem though...You'll see that a 6mm (or 1/4 inch) thick panel is built up with 5 layers of birch veneer of the same thickness...a 4mm panel has 3 layers...a 18mm one is made with 15 layers...
1: What's the color:
The stuff looks like this...a bright sand color...Exposure to the sun will darken it...
2: Structure and flames:
In this example you see "Flames"...Imagine that you put a chunk of birch tree in a lathe and spin it around...imagine that you slice off 1mm or 0.0393701 inch of it in a continuous process...You would end up cutting through the year-rings of the tree...This is the result of this process...you see different shades which look superb on a plain varnished deck ;-)
3: Patched up stuff:
While slicing that tree into a veneer ply you'll cut through places where branches were attached to the tree...we call them nuts over here...
Such things are structural not too sound and are removed and filled in with a better piece of ply...
It's done because the ply producer wants to get the maximum out of a tree...yep it's a money thing...but a good one...Better use of a tree makes them cut down less of them...and that's good for future generations!
4:Birch plywood Layers:
6mm (1/4 inch) birch has 5 layers of veneer (5 ply)...those veneer sheets are glued in a factory using a huge, heated press...
Each layer has the same thickness...
Sticking 2 of those panels together gives you a 12mm thick deck...the dark line you see is caused by the glue I used...that was Aerodux 185...Epoxy resin is nearly invisible...and the best stuff I used for the moment ...
5:Finaly:
There could be other types of wood that are use-able...but I never tried them because of having the right results with birch plywood, using my own 2 panel technique...
You could also have a go at making your own plywood by glue-ing veneer sheets together on a foam mold and with the vacuum bagging technique...must be some effort!

Good Luck!...Ive
6:More facts !!!:
Elliotfrom California sent me a mail with some more info on plywood, especially on the term used for the wood we need to build decks:
Hey,

I live stateside in California and was recently constructing some boards. Firstly I must say great site, its given me much information. My real point is to suggest you emphasize the use of BALTIC birch, not just any birch. You may know this already but its something I just found out. You could throw this in under the wood/ birch section on your site. Most hardware stores such as Ace, Orchard Supply Hardware or Home Depot, (possibly also Lowes) in my area will offer birch in either 1/8 or 1/4 but are both 3 ply and simply a veneer top that is birch. This stuff is NOT SUITABLE FOR BOARDS MAKING, PERIOD. I've gone through about $30 or $40 usd worth of wood before I realized this. Baltic Birch from what I understand will almost always come special order for about $20 (mine is 21.50 usd). You can tell its what you need by its 5 ply construction of all birch. Its 1/4" and comes in 5x5 boards. Not many stores stock it. I'm not sure about getting 1/8 inch.

Once again thanks for the great site.

Elliot
So, from now on I should use the word Baltic when it comes to mentioning plywood !
This sure will avoid mishaps when ordering or buying the wood needed for building decks :-)
Thanks again Elliot!!!

Cheers,

Ive " Toothless" Vandewalle