Hardboard/Eucaboard for urban streets?

[Jetrock]

The Milwaukee Road Warrior

Has anyone done this?  I'm going to give it a try because I already have the board, but I think I need to somehow seal the board before painting it.  I've not used styrene for anything yet and don't have a comfort level with it.  I know many people cut styrene for roads.  I've cut a lot of hardboard with my jig saw and it looks pretty good as a road material.  Some of my roads I've modeled with Quickcrete too.

I've used Masonite type hardboard for roads, including sections of my layout that have street running, with either styrene strips or Durham's water putty to fill the gap between the outside of the rails and the edge of the hardboard. I attach it to my benchwork (1/2" MDF, which I know everyone besides me hates) with wood glue or Liquid Nails. I did this after creating street trackage using .020" styrene on top of 1/8" foamcore, which started to bubble and flex badly after a few years. I painted the hardboard with beige spray paint and Woodland Scenics aged concrete street-coating system. I like the results, which are both stable and secure, and look all right; in some parts I have "superdetailed" the sidewalk by drawing in cracks with a fine-tip art pen. No issues with flexing or separation from the table, but I live in a very dry climate.

 

[NScale4x8]

Latex primer on the visible side should be adequate sealant. I wouldn't paint the bottom side. Regular wood glue will adhere to the raw hardboard. Glue adhereing to paint is less certain.

If you plan to model expansion joints or cracks, I would scribe them after priming but prior to painting any top coat. Use thin paint mixture(s) for the final top coat. Avoid anything glossy.

I like "hard board". I have used Luan and Masonite. The Masonite I purchased was already primed on one side.

 

[The Milwaukee Road Warrior]

Has anyone done this?  I'm going to give it a try because I already have the board, but I think I need to somehow seal the board before painting it.  I've not used styrene for anything yet and don't have a comfort level with it.  I know many people cut styrene for roads.  I've cut a lot of hardboard with my jig saw and it looks pretty good as a road material.  Some of my roads I've modeled with Quickcrete too.

I used the same hardboard for my coved, painted backdrop around my entire layout - without sealing.  I simply primed the painted (visible) side of the backdrop with a couple coats prior to painting my sky with latex paint.  Still looks great.  

I assume I can do the same for my urban roads, but knowing what I know now about hardboard I'm thinking I probably *should* do more than just a couple coats of primer on the visible side.  I've seen some people suggest polyurethane, others linseed oil, epoxy resin, other various stinky options..

Soliciting opinions here on the easiest way to avoid potential warping.  Should I pursue one of the above options or keep it simple and just apply primer to both faces of the board before painting the visible side for my roads? 

I have a commercial grade dehumidifier in the basement that maintains 35-40% humidity year around; I've had no issues with my backdrop in 4 years - not even the joints showing thru where I spackled them over with DAP.

Thanks