Has anyone come across those formed plastic-of-some-type trays that you can put in valleys where the slates from each side will butt up to those on the other side (so no plastic /lead showing) ...?
Any issues with this product? (eg type of plastics used, design quality ...)
Any issues with this design (eg prone to blocking?)
All comments very much appreciated

Quite often got asked to GRP valleys. These were usually existing ones that had started leaking. Easy enough to make your own if you know exactly what you want.

I have a "sanded" interlocking concrete tile roof, now about 30 years old. The moss growth on the north facing slopes has been incredible and is adhering to absolutely every thing. If I had a valley, as described by you, I would have a series of little dams all the way down the slope with the tiles themselves leaking. I would always go for wide valleys which are easier to keep clean. Not sure about plastic, it expands and contracts a lot with temperature and perhaps, degrades with the UV. has any one seen any 60 years old plastic rainwater goods?
Frank

Thank you all, so far ....

Posted By: RobinBhow bad would lead be?

it's a cost thing ... material, and labour/time ... and the look of it (Had a pic but having problems uploading it)

Posted By: chuckeyI have a "sanded" interlocking concrete tile roof, now about 30 years old. The moss growth on the north facing slopes has been incredible and is adhering to absolutely every thing. If I had a valley, as described by you, I would have a series of little dams all the way down the slope with the tiles themselves leaking. I would always go for wide valleys which are easier to keep clean. Not sure about plastic, it expands and contracts a lot with temperature and perhaps, degrades with the UV. has any one seen any 60 years old plastic rainwater goods?
Frank

The plastic would be protected from UV by the overlying slate ... which is "flatter" than interlockers so I'm not sure if the same mini-dam effect would apply (?)
It's supposed to be easier to keep clean as the tiles will be cut to fit, but maybe there is bound to be a kind of silt build up over the years, under the slates which would have to be jetted through from the top maybe ??

Posted By: fostertomAmazing! I woke up this morning with exact same question.

That's the third time now! are we separated twins? When's your birthday?!

Posted By: SteamyTeaQuite often got asked to GRP valleys. These were usually existing ones that had started leaking. Easy enough to make your own if you know exactly what you want.

Do you mean GRP were leaking?
Make my own with plakky or did you mean lead, like RobinB?

Keep em coming!

How about galv steel (industrial guttering) or zinc etc as alternative to lead, esp if protected from the elements by close-mitred tiling?