"Dave Liquorice" wrote in
ll.co.uk:

On Tue, 30 Mar 2010 19:35:01 +0000 (UTC), Al 1953 wrote:

I purchased tongue & grooved redwood floorboarding (22mm x 135mm) to
be exact.

Yipes, I hope you've thought about the weight and the hinges to
support them...

Well, I bought four very hefty galvanised hinges costing £17 a pair. I'm
more concerned about the strength of the framme and its attachment to the
wall than anything. I've used 120mm hammer fixings ( 4 per vertical). I
now wish I'd applied preservative to all faces before fixing, but too
late now.

For the bracing' I'm thinking three equally-spaced horizontals with
diagonals in-between. I am planning to have no vertical bracing at
the edges, as the tongu+grooved timber is nearly an inch thick, and
seems very rigid,

My gut feeling is that won't work, or not work as well as diagonal
across the corners of a box. I can't pin down why I feel it won't
work, other than "no triangle". I could be wrong, the fact that you
have 3/4" boards might be enough but they will slide past each other.

Now I understand bracing better, I'm thinking maybe have the braces
parallel, like this:

http://shedbuilder.info/How-To-Build-A-Shed-Door.html

No jambs/verticals in that design either.

I wouldn't the boards will want move and if glued they can't. I
wouldn't be surprised to see 1/4" variation across the width of each
of those boards between the "wet" and "dry" states of the timber.

I've since read that priming the tongues and grooves prior to assembly is
considered sensible. Thanks to you, and all others, for the other
suggestions and advice.

Al