What products are suitable for my low pitch roofs?

[snapd]

I have two lean to extensions and a conservatory. They are of a low pitch, around 15 degrees.

I would like to have them reroofed. Currently they are in cedar shingles, which I understand is a lightweight product.

According to the survey I had done:

• The lean to extensions comprise "75mm x 50mm rafters at approximately 400mm centres"
• The conservatory comprises "100mm x 25mm rafters at approximately 400mm centres"

One builder suggested Redland Cambrian, however I'm in a wooded area and I've read stories - for example, here https://www.diynot.com/diy/threads/low-pitch-cambrian-tiles-leaking.464038/ - of the channels becoming blocked with debris and them leaking.

Another suggested Marley Thrutone, but they don't look suitable for the pitch of the roofs.

Would my roof structures support a heavier product than cedar shingles? Does anyone have anything suitable in mind?

 

[Alastairreid]

 

[mrrusty]

It may not be recommended, but our 1902 house (and I expect many many others) has a slate roofed single storey extension at the back which is at 15 degrees. The lap isn't much more than 100mm either. The house has been in our family for ever, and it's never been a problem. We recently had it re-slated reusing the old slates, and the new roof is absolutely fine with similar lap.

If it's a fairly sheltered spot, IMHO ordinary slates are an option.

 

[catlad]

It doesn't sound like your roof has been designed to take much weight.