Recycled-plastic panels for siding (as an alternative to plywood or MDO)?

Hi there--long-time occasional lurker, first time poster. I've been chewing on siding options for a buildup, and I'm looking for data on whether or not 4x8 1/2"+ panels of recycled plastic would be suitable. They're kept with the plywood and MDO at home stores. Seems like it would be a very quick install, and affordable in terms of materials. They are incredibly stiff and durable-seeming. Unlike MDO or plywood, I would never have to worry about moisture penetration, and my main questions are about how they'd handle the most extreme temperatures (20 below F, or full sun at the height of summer), and somewhat less importantly, whether or not they're easily paintable. Would they crack or warp? Are they dimensionally more stable than many-wafered ply material? If they're not easily paintable, I could still consider it. As is, they're kind of a medium dark gray. Whatever I choose, I'll be trimming it out with hardi-plank around the windows, and with a belt/band-board between this siding and the stucco at the first level. Any thoughts? Any experience with this? Are there other threads on this that I've missed? Anybody done this or seen this, elsewhere? Thanks in advance for any input.

OK, well here's an answer I've gotten so far--anyone confirm or deny? ===================================================================== The simple answer was: "Not such a hot idea". It's unlikely that the material is treated for UV, and plastic breaks down when exposed to UV. It will expand and contract in the extreme temperatures. And no, it cannot be painted. He mentioned a material called "Thinply", and said it seems to hold up well.

Short answer - Not such a hot idea (sorry for the pun).

 

Bit longer - depends on a lot of factors, but not such a hot idea.  I've some experience with thermoforming and high pressure injection.  Plastic at 200 degrees coming off or out of a tool will shrink quite a bit before it cools down.  There's formulas and what not to figure that out based on material in order to properly size a tool, but the point is that yes - you're going to see expansion and contraction (enough to cause problems)- but most materials you put on your house will also do that.

The difference is that most preformed siding, whether plastic or aluminum or steel has slots and lap joints in order to accommodate the expansion and contraction.  Nailing plastic willy nilly to the side of your house will just end up warping and popping off.

If its recycled, it’s probably some grade of HDPE, which is extremely unstable when its comes to expansion and contraction.  And you can guarantee there won't be any UV additives, so whatever your finish there is, will degrade.

As far as painting - yes, you can buy special paints, but HDPE outgases, well, oil, basically, and nothing conventional will stick to it.  I've even experimented with trying to get bed liner to stick to HDPE before (for a shipping application), and it ended in a mess.

So - yeah, sorry.  If you want to go for that look, you'll have to find something designed for siding, or spend a lot of money for a more stable resin that has a UV additive, but I think that goes against your original hope - cheap.

 

Mike

 

Thanks, Mike. That's exactly the kind of experience I was hoping people could draw on when I posted my question on this site. Much appreciated. I'm wary of moisture penetration in MDO, so I guess that for price, I'm still looking at corrugated metal or maybe tongue-and-groove cedar, since I am not a fan of lap vinyl/metal/cedar in this case. The $11K for Hardi-shake panels installed may not be much for most budgets, but it's too high for mine. Thanks again.