Relocating Ducted Heating to wall with no clearance!

HI all, first day of my house extension and i have stuck a problem.

We have an exsisting ducted heating system that is on the part of the house that is being demolished, i have a walkway on the side of the house that is basically dead space and i am hoping to put all our services (water tank, water heater, ducted heater) on that side of the house.

The problem is there is a slight slope on the block and that side of the house only has about 100mm of clearance so we'd have to dig down about 200mm to install the unit obviously it'll rust out pretty quickly.

I have the option of excavating the side of the house and gaining another 100mm or so, i am not not too sure what i should be doing? Any idea's would be appreciated.

I am in Melbourne/Preston if that makes a difference.

Thanks
Joe


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