Lateral support strips

You could add a lateral support between the studs to attach the bottom and top of the masonite / hardboard.

Support Frame

I used 1/8" but I made a frame our of 1x2 just like building a wall. Te frame is screwed to the top of the bench work then the masonite is attached to it. Provides the necessary support and the biggest advantage here is that it is not attached to the wall of the basement.

Greg

Other concept

I have a double peninsula on my new extension on my layout.

Because of dust, the necessity of sanding and anything I really did like I use a suspended vinyl  backdrop all around my layout, sweet corners, no any joint and no crack in the future.

Just a suggestion

1/8" hardboard here.....

and I covered that with vinyl flooring so there would be no cracks.   If you do go that route you can use the vinyl for the corners too

Masonite alternative

Hi,

There are some great examples of people using galvy or aluminum trim coil for backdrops.  Once I can get to the store again I plan on checking it out and trying it.  Several ways to support it include punching holes in the edge with a snaplock punch and hanging it from a J channel, or adhesives.  Major advantages are easy small radius curves and less seams.  Sounds good to me.    

Jeff

links:

https://www.nmra.org/sites/default/files/sr201202_alumback.pdf

https://forum.mrhmag.com/post/the-hills-line-how-i-learned-to-stop-worrying-and-love-loctite-12212446

One other thing

I use this both on the backdrop and the front of the bench work, there are few square corners on the front of my bench work. For corners I rip 1/4" plywood into 3/4" strips and attach the first strip in place on the outside of the background frame (this is later removed). I then build up the curve bu gluing together strips until the curve is the thickness of the frame. I then remove the first strip and glue the finished curve in place. Depending on the size of the curve you will probably have to add uprights between the upper and lower curve pieces.

Greg

@Marc - suspended vinyl

Marc what is "suspended vinyl"?

@remhed

Suspended vinyl floor; it's not often seen in US but in Europe there are severals layout which use vinyl floor as a backdrop.

The Floor vinyl is suspended on support,; generally a wood frame were the vinyl is sandwiched or glued on the top  to be hanged.

For the backdrop, generally the back side is used.

The advantage is no join first , natural smooth corner; it's held paint well like latex and he is durable; in final it cost less than a whole assortment of masonite panel

There is no  need of making join and dust to finish the backdrop, no crack in the future

These roll of vinyl floor come in different width from 3' to a like 6' and a length which can reach 150' ( in Europe here in USA I  don't know.

The only difficulty when you put it in place, is the necessity to be plumb and square and keep this level all around.

It's also ready quickly because don't need big work, like cutting, sanding

I will use it on my future extension of my layout.

Vinyl flooring in the US

I have this as a backdrop on my layout. Sort of a mixed bag of results. 

Here it comes in widths of 12ft (~2m) and as long as you want it. I got two 24" (330mm) strips and one that was around 30". One of the larger ones went across a window (so-so) and the Garage Door. The 24" ones I tacked end-to-end and they go down the center of the peninsula on the layout. Those are supported by zip ties connected to threaded rods and run through zip tie pads super-glued to the "decorative" side of the flooring. 

I may not have enough rods for support - it isn't self supporting at all, and has some sagging issues. 

Wow, vinyl flooring, who

Wow, vinyl flooring, who would've thought!  Since my layout is around the walls, basically, I hand painted the backdrop on finished drywall.

Maybe I'm not understanding, but the OP said peninsula, so it's like a view block, down the middle of the peninsula?

I'd probably dry wall it, if your going to cover it with something else, no need to finish the drywall, it will act as the support.to whatever your finished backdrop will be.

Cellular PVC board

I would take a close look at PVC board,...cellular PVC,...1/8" or 1/4". Can be purchased in 4x8 sheets.

I've used it here on my turntable pit reconstruction. Have a look at the pit wall,..
https://forum.mrhmag.com/post/diamond-scale-turntable-korber-roundhouse-repairs-12214967

Vinyl

I used vinyl flooring, back side out, on my last layout, which was an around the room layout, about 75 total feet.  I screwed it to the wall at the top, using large fender washers.  This was about 16" tall, if I remember correctly.  I then installed a suspended ceiling grid over just the benchwork, for lighting/diffusers, and the grid was placed just below the screws/washers.  The bottom part was also screwed in place, and scenery covered up those screws/washers.

I primed it first with a couple of coats of gesso, then a friend painted it.  One advantage of this method is that you can achieve very tight radius curves in the corners.  Same would apply, in reverse, for a peninsula, if you wanted to wrap it around the end.  

As Jeff said, it isn't self-supporting and can sag unless you affix it somehow to a backing.

Al Carter, Mount Vernon, WA

I use .080 styrene. You can

I use .080 styrene. You can get it in 4X8 sheets. I support it with either 1X2 strips along the top edge on walls, or using 1X2 posts off my benchwork on peninsulas. It easily splices into seamless longer sections using a splice plate (on the back side) and the gooey type of Testors model cement (liquid cement doesn't work well), then filling the butt joint on the exposed surface with plastic filler and sanding smooth.

It easily curves, even down to less than a 6" radius (though that tight is a bit less easy to do).

Here's a couple pics. Wall mounted (in the back, obviously):

And peninsula mounted. The peninsula mounted one was double-sided, curving back on itself at the right end (the clamps were holding the curved end (on the other side from this shot) to "set" the curve a bit. They were there for about a week before a new section was spliced in:

And the opposite side after painting:

Nice Mark P, The plastics,

Nice Mark P,

The plastics, styrene or PVC, work well here. I think better than masonite.

Styrene on plywood

What I tried on my N scale layout worked out pretty well - plywood backing in places with a roll of styrene.  The vertical plywood pieces were pocket screwed to the layout sub-surface (plywood).  That’s it, no other bracing.  Pocket screws are plenty strong enough for that, and it means you only need a single piece of plywood to act as a backer for the backdrop on both sides of the peninsula.  I only used fins where there wasn’t a curve in the backdrop.  The plywood “fins” in place, with the roll of styrene that will become the backdrop surface in the foreground:

More pictures around that phase in this blog post:  https://rices-rails.blogspot.com/2011/07/foam-on-palmer-industrial-park.html

This photo gives you a good overview of what it looks like after gluing on the backdrop and getting the initial sky blue paint on:

More details and pics in this blog post  https://rices-rails.blogspot.com/2011/09/palmer-industrial-backdrop.html.

The styrene is flexible enough to make nice curves really easily, and to take bumps and minor abuse without damage.  But it’s stiff enough so you don’t have to support it everywhere.  And the roll means you have long stretches with no seams - the entire backdrop on that layout was a single continuous piece.

I second the Styrene

Like a few others have said styrene is an option worth considering.

In my opinion styrene is by far the easiest to handle and put up as your backdrop. The 4x8 sheets of it you can get from your local plastics supplier can be easily coiled for transport home.

Compared to masonite it's easier to handle due to being lightweight and the score and snap cutting make it simple to cut without a mess to clean up. Whether you glue or screw styrene to any backdrop supports, any seams or holes can be filled with autobody putty and sanded smooth.

I tried aluminum trim coil and found it to be dangerously sharp, difficult to hang without wrinkling and easily dented.

The first part of my layout has a masonite backdrop and I can tell you for sure the rest of my backdrops will be styrene.

Vinyl Flashing For Backdrop

Mr Rice: I understand you used vinyl flashing. The paint you used was latex?  Did you use a brush or roller to apply it, were you happy with the smoothness of the finish, and how has the paint held up? Thanks.

Painting vinyl

I brush painted it.  It came out pretty well.  It held up just fine for 6 years until I had to demolish the layout to move.

I use plastic corrugated

I use plastic corrugated signs, the price is right

My goal was to hide the cinder block wall, not make a work or art.

I used plastic (PVC?) sheet on my Nscale layout.

It’s flexible and lightweight. For the most part I liked it. The kind I got was shiny like pvc pipe. It didn’t take latex paint very well. I had to buy a minimum of 3 sheets from the supplier which was more than I needed.
 

I went with Masonite for the new HO layout section. I wanted the backdrop to make a stiff box because I eventually plan on making a dust cover/ ceiling and I didn’t want to engineer a frame to support it. The Masonite didn’t curve very well to a 12” radius curve. It snapped a little bit even after wetting the back for 20 minutes. The other thing on a section is that the Masonite doubled the weight of the section when it was installed. Moving the section will be a two man job if it’s ever needed. 
 

I am not sure yet how I will finish the rest of the room. The plastic seems promising for most situations but make sure the surface takes paint first. 

Sheet styrene cost and supplier

Those of you using sheet styrene what did a 4x8 sheet cost?  In did some quick googling and I see hi impact styrene but that is like $70 a sheet. 

  "Past layout I used

I'm using 1/8 masonite on my current layout. I have 16 in on center supports but I'd be wary of 24 in spacing. Perhaps you could add horizontal furring strips at top and bottom to discourage warping?   If there is not a lot of curved areas you could use 1/2 inch sheetrock on the straight areas and thinner material on the corners                     (masonite, plastic, etc.) Sheetrock is the cheapest and easiest to finish material, that's why it's so common on house interiors......DaveB

Cost and Where to Buy Styrene

I've always used masonite, but am intrigued with the styrene applications,  Like Steve above, I googled it and the plastics supply houses that seem to carry it or a long way from me.  Where are you guys finding .060 and .080 styrene in 4 x 8 sheets?  How much is a sheet?   I'm seeing it around $70 and I can buy 6-7 sheets of masonite for that price, and HD/Lowes are 10 minutes away.  

Thanks,

Craig

Plastic Sheet at HD

I saw some 4x8 plastic sheet at Home Depot about a week ago. I think it was some sort of wall covering made from reground PVC. It did have a small texture on one side but this could always be faced to the inside of your backdrop.

Just a quick look,..
https://www.homedepot.com/p/1-16-in-x-4-ft-x-8-ft-Plastic-Panel-63003/202090190    20-25 per sheet

Did a second look, here is the material I saw,...
https://www.homedepot.com/p/PLAS-TEX-1-16-in-x-48-in-x-96-in-White-Polywall-Plastic-Panel-10048615/311314398?MERCH=REC-_-pipsem-_-205079515-_-311314398-_-N