15 meter zinc gutter, flex enough to bend a little (0.5 degree)

guttersslope

I have a flat roof, ~ 150 m2. The roof is under a ~ 5 degree slope.

Since the roof is approx 15 meters long (by 10 meters wide), I was thinking to make (on the low side) the high point of the gutter in the center of the wall. Then install the drains on each side (125mm dia).

           drain          CENTER         drain
           (low)          (high)         (low)
             |--- 7500 mm --||-- 7500 mm --| 
             |                             |
        (0.5% drop)                   (0.5% drop)

I would like to use zinc gutters (½ round), but I'm a bit concerned how to connect these at the center.

If I buy a long piece of zinc gutter (~ 6-10 meter), would this by itself be flex enough so I can achieve a 0.5% drop/pitch? Or would I need to solder two parts in the center under an angle?

Thanks!

Simple sketch

Best Answer

Galvanized steel will easily take a small strain like that. The normal yield strength of steel is not reached until total strain is 0.5% strain. That is ,it would need to be held in place to prevent "springback" at 0.5 strain. However , 0.2 % is permanent strain ( no springback). Or , extreme case ,you bend it slightly ( I doubt that will be necessary). If you want a 6 m ( about 20 ft) length with no seam you will need to use aluminum , not galvanized steel.

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