L-girder plywood for support

The whole point of using L-Girder construction is to avoid placing plywood everywhere. The open spaces between the girders provide areas for scenery creations that just aren’t available with table-top construction.

The L-Girder technique is VERY strong.

I understand that you can even do L-girders with 1 x 3's and they are still strong with reduced weight.  Is that right?

John

@Craftech posted:

I understand that you can even do L-girders with 1 x 3's and they are still strong with reduced weight.  Is that right?

John

That is correct. That is how I built my layout.

As far as width. How far apart do you think is the maximum distance between the legs that you cross brace together? Not length, the width.

L-girder construction certainly works but you can also build 1 x 3 framing that is rigid without the plywood on top. Keep to 16" centers.

As far as your question on how far apart cross braced legs can be the answer depends on several factors. How rigid are the cross braces, how well are they attached to the legs? Do the legs really need cross bracing? Bracing can lose lateral rigidity the longer it gets, but 4 - 5 foot span is doable. As I mentioned in your other thread gussets can do a lot and you may not need cross bracing.

I don't mean to sound like I'm trying to talk you into one way or the other, just offering options.

@Craftech posted:

I understand that you can even do L-girders with 1 x 3's and they are still strong with reduced weight.  Is that right?

Absolutely!

I just uploaded a new OGR video to illustrate the process of building L-girder benchwork. The video also shows how strong it is, using 1x2, 1x3, and 1x4 lumber.

However, you must be an OGR Digital Subscriber to be able to watch it.

An excellent resource for L-Girder construction is Linn H. Westcott's book "How to build Model Railroad Benchwork."  If the girders are properly braced (e.g., diagonal strips from girder to leg), plywood atop the joists can be minimal.

L-Girder benchwork is VERY strong!

Here's a frame grab from the OGR L-Girder video.

With George and me up top, that's almost 400 pounds of us, sitting on a 12-foot long L-Girder span, made with 1 x 3 and 1 x 4 lumber, with 2 x 2s for the legs.

@Bruce Brown posted:

An excellent resource for L-Girder construction is Linn H. Westcott's book "How to build Model Railroad Benchwork." If the girders are properly braced (e.g., diagonal strips from girder to leg), plywood atop the joists can be minimal.

Ditto. 

That would be this book...

It was my "Bible" when I built my first two layouts.

One of the best books ever written for us!  How to build Model Railroad Benchwork Linn Wescott--BUY A COPY...I have had mine one for closing in on 50 years.

Love the L Girder design. A friend and I built an 8' x 12' in a day. It is very strong. I went overkill on mine. I put 3 sheets of ply and Hoamasote over mine. I know that L Girder allow for seperate scenes, per Rich M, but I love what I have. It is working out well

Joe Gozzo

L-girder is inexpensive, quick to build, incredibly strong, and adaptable to many configurations.  Aside from that, it doesn't have a whole lot going for it.

Unless one is building a modular layout or one that needs to be able to be shipped, IMO L-girder is the only way to go.

Agreed. We'll hopefully be starting to build our benchwork at Christmas time this year. It will be L-girders made of 1x4's and 1x3's for the top flange.  I've used 1x3 flanges in the past and like the extra room it gives me.  Then we'll use 1x4's for the joists that sit on top of the L-girders.  The table top will be plywood (haven't decided yet if 1/2" or 5/8") w 1/2" homasote (roadbed) on top of the plywood.  We'll use cookie cutter construction on the plywood and homasote roadbed.  If we get it started after Christmas, we'll post some pics.  Both the Linn Westcott and the Jeff Wilson (basic model railroad benchwork 2nd ed ) are excellent ref / how to books.