Appropriate roof pitch

I am building a shed in my back garden and propose to roof it with tiles. However, I would like to keep the pitch of the roof as low as possible. I would appreciate any advice on how low I can go. A friend has suggested 30 degrees but would it be possible to go any lower?

We have a roof with 22 degree pitch using specialist tiles from CRH.
You can go lower than 30 degrees but need specialist materials for it.

It depends on the type of tiles you want to use, 13 degrees (Roadstone Centurion ) is about the lowest. Have a look here [broken link removed]

Hi guys. Thanks for the information. However, I propose to use a stock of tiles that I have from when my house was built (about 40 years ago) rather than a new specialist low pitch tile. The name on the tiles is "Weatherall". Do you think I would be able to use a pitch of around 25 degrees for this old type of tile or would I have to go to a 30 degree plus pitch?

Thanks.

Apologies but the name of the tile in question is actually "Weatherwell"