Plastic vs Zincalume?

[PRejto]

I'm contemplating a smallish shed to which I hope to add a roll up garage door type of roof. I'm noticing a very large difference in price between plastic and zincalume sheds and wonder what the benefits might be for either type in terms of protecting equipment and supporting the weight of a roll up roof?

see: http://www.iceinspace.com.au/forum/showthread.php?t=57691&page=2 (Post from Martin Lyons)

Perhaps this has been answered before....if so a point towards that post would be appreciated!

Peter

[steve000]

I cant comment directly on the durability etc of the materials but id imagine over time the plastic door would perish where as the metal wouldnt. Because doors are generally designed to be vertical and sort of covered not acting as a roof.

HOWEVER! if if were to hail if the plastic were to survive i think it could be better then metal as id imagine dints etc could deform the metal making it difficult to roll back

[gregbradley]

When you say plastic - what type of plastic? I did not know you can get plastic roller doors.

Generally though, unless the plastic is polycarbonate which is the material often used for sheet skylights or backyard pergola roofs it will deteriorate with UV.

Plastics also tend to dry out and get brittle unless high grade but apart from Polycarbonate and to a lesser degree fibreglass I am not aware of a roofing material which is UV resistant that is plastic (oh, there is one used for an artificial slate tile).

So Zincalume will almost certainly outlast a plastic in a roofing application.

Also in the case of a hail storm, plastic will not stop large hail unless really thick and if it were weakened by years of exposure to heat and UV and get a bit brittle is very likely to let large hail through. This then could decimate your scope and perhaps damage a mount.

I have only seen hail penetrate a colorbond/zincalume roof in some rare instances where the hail decimated anything else. If the hail were large enough to dent zincalume (large - like oranges) then the risk is it would penetrate a weakened plastic door.

Greg.

[PRejto]

Sorry guys, I was pretty unclear in my first posting! I actually wasn't speaking about the roof material, just the basic shed! (I fixed up that first post.)

After searching for weeks, re-measuring the deck space, etc, etc, I've changed my mind about what I am going to do. Instead of a shed with a rool up roof I'm going to construct something smaller that rolls off the telescope. The nicest one I've yet seen is here: http://mmerino.com/resources_astrophotography_roll_off _shed.htm

I've seached for something prefab but so far no luck. (I need a shed about .75D x 1.2 W x 2H meters.)

[jenchris]

I have a spare roller door complete if anyone wants one. I replaced it with a Bay window

[DavidU]

My factory had a full length plastic skylight, the hail smashed it to bits and ruined my factory.I will never trust plastic on any important roof.
http://www.iceinspace.com.au/forum/showthread.php?t=57967&highlight=hail

[gregbradley]

Not sure what your carpentry skills are like but try knocking one up yourself.

A simple contruction method is to use the 3mm thick L brackets Bunnings sells and 45mm hexhead roofing screws to join 75 x 35 pine together with.

Its simple, its easy, it only requires an electric saw and a cordless drill and a hexhead screw driver bit for the drill. If you need to adjust something you can simply unscrew it very easily.

Roof is simply colorbond corrugated (zincalume is very reflective and looks a bit cheap, you'll only need a small amount).

You could use 100mm C purlin on its side from Bluescope steel for your tracks and have the wheels go on the inside of these so the shed can't blow up and off the rails.

Greg.

[Tandum]

There's a neat one on CN (http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/4496708/page/1/view/collapsed/sb/5/o/all/fpart/1):)

[Waxing_Gibbous]

Plastic or Laserlite is a doddle to work with but doesn't last like ZAl, or indeed as Dave pointed out, protect nearly so well.
Bunnings sells stuff called "ripple" sheeting which is quite lite weight and easier to work with than full 3mm roofing. The downside is, its pretty dear (about $17.00 for a 1mtre x .5 metre sheet - more for bigger).

I'm going all tradish and making mine out of white weatherboard & this stuff.
All my other designs look like dunnies. :D

[PRejto]

Yes, it looks like I will build one myself.....just feeling lazy. Thanks for all the good suggestions of building materials! The Tardis is really cute....