Outdoor stone tiles on plywood - apsphalt felt?

[Gord66]

I am rebuilding a raised outdoor terrace. The flooring will be stone tiles set on 18mm plywood. I know that I need a waterproof membrane between stone tiles and plywood but need help with what to use:

- is asphalt felt (primarily used for roofing) a suitable material for this? If so please could somebody recommend the type/quality/spec I need for this type of job because everything I have seen is only supposed to last for 15 years which is not good enough - I don't want to have to replace it that soon if at all.

- Is there another material (apart from asphalt felt) that would be better/more suitable and durable?

I'd appreciate any advice/help

 

[Karis]

Sorry to burst your bubble but laying stone tiles on 18mm ply base ain’t going to work outside my friend. Even if you used the thickest WBP ply available, a wood tile base outside will be doomed to failure most probably after just one season. 15 years! you’ll be very lucky if it lasts 15 months, you need to rethink your project!

 

[Gord66]

I'm reconstructing a terrace which was done this way originally and has been there for 15 years; its pretty sturdy - there are metal and timber joists below the plywood - but I'm having to replace it because water has been getting through the tiles and the asphalt to the timber underneath. I would just like to know if I should use asphalt again between tiles and plywood to prevent water getting through or is there a better method