Extending the life of exterior ply exposed to rain

[RJS]

The endless carport rebuild approaches the point at which it can be roofed. Prior to doing so I have to fit the sides where it extends over garage and rear extension. My plan is to use exterior ply panels. These will be removable once the carport is roofed to allow for easy replacement but I want to increase their life as much as possible. What can I treat the ply with? Any rain which drains off the treated surface feeds a pond in my back garden and which contains newts. Therefore I can't use anything that is hazardous to fish etc. I've looked at Creoseal which (a) doesn't soak into the ply, (b) has a nasty oily run-off and (c) according to the tin is definitely not fish- friendly.

TIA

Richard

[Harry Bloomfield]

RJS expressed precisely :

Could you instead use plastic soffit panels? Fit and forget.

[harry]

Well you can use marine ply but it costs and arm and a leg. Why don't you use plastic coated steel roof profile. The suppliers cut it to size for you.

[newshound]

+1, used this for walls and roof of a little lean-to shelter

[Grimly Curmudgeon]

Nothing. It lasts for absolutely years as it is - provided it's decent quality in the first place.

[RJH]

I had an offcut I found in the garden at my old house. I used it a as temporary cover to the kitchen drain, stop leaves getting in. I never treated it - still in tip top condition some 6 years later. Amazing stuff.

Rob

[RJS]

Will - either temporarily until a better solution is found or permanently because I will stop looking for one - fit the bits of exterior ply and monitor their deterioration!

Ta to all.

Richard