Over 10 years ago we built the Mother of All Sheds.
The roofing was corrugated steel sheet with a green plastic coating.
This last year the coating has started to lift off the areas which have been in full sun.
I guess some remedial painting is required. How long would the team expect the original coating to last?
Cheers
Dave R
That will depend upon the environment. One manufacturer of such coatings say their product should last between five and 200 years. The former in areas with heavy industrial or marine contamination. The latter if used underground.
200 years? Reminds me of Woody Allen:
About 5 years in full sun if you are lucky.
Hot tin roofs and plastic coatings are pretty well doomed to fail quickly since the plastic expands much more than the metal and the whole thing will get insanely hot in the sunshine for good measure.
Eventually the plastic will go brittle due to a combination of ozone and UV damage then it will sheer off in flakes at the metal surface.
White plastic with a UV inhibitor should last the longest since it will absorb less sunlight and still radiate thermally like a black body keeping the roof a bit cooler will help.
There may soon be designer materials that stay cool in direct sunlight and are cheap enough to use on roofs.
I was convinced it was the other way round, but you are absolutely right. The coefficient of expansion of polythene (for example) is roughly 10 times larger than that of steel.
David formulated the question :
My garrage roof and workshop roofs, are steel, galv coated then some sort of paint or plastic coat. The must be around 10 years old now and absolutely no sign of any deterioration. Both are in full sun much of the day. A local very large industrial building used the same material for its walls, it was still in good condition 40 years after the build.
In message <t43pom$hhp$ snipped-for-privacy@dont-email.me, Harry Bloomfield Esq snipped-for-privacy@harrym1byt.plus.com> writes
I have built/re-clad several farm buildings with AS35 box section plastic coated steel sheet. So far (25 years) only one is peeling on the sunny side. Steadmans, the manufacturer guarantees 20 years away from a coastal environment.
I was going to say the decent quality industrial stuff lasts decades. I have some of the cheapest budget stuff available on a sort of lean-to that was only going to be temporary, and that's lasted ten years.
About a mile or so from the sea, me.
:-(
Dave R
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