What happens if you use interior gloss outside?

[treacletart]

Would it be disasterous?

no but it wouldn't last anything like as long as proper exterior gloss, which is more hardwearing and less likely to fade in colour, so probably not very cost-effective.

I guess it wouldn't be very resilient to the elements so would need re-doing very soon afterwards.

Yep, I did my wooden conservatory with interior one and it lasted only a few months of scorching sun and rain.

Sorry forgot to say that paint peels off.