A reader's General Construction question: MDF outdoors?

Chris R.   from   United Kingdom   had this question about using MDF outdoors.

Hi Bill, I was wondering if you could help? I have been trying to find out if MDF is suitable for use outdoors? A builder said that he would use it for new gates to a covered area we are planning to have renewed at the side of our house but I am not convinced.We have postponed the work while I check this out.
I found your site by googleing and think it is very useful. Thanks

Bill's answer

Hi Chris,
I would be more than a bit wary of using MDF outside. My thinking is that you would be placing a lot of faith in the sealing or painting of the edges. I am not saying don't use it, but you would have to have a good reason.
I have used solid timber and steel many times for gates but never considered MDF at all.
Cheers
Bill