Dormer Valley Detail

14 Nov 2019
Reaction score
United Kingdom
I noticed a damp patch on the sloping part of my bedroom ceiling under the dormer cheek and had a look on the roof and the where the dormer valley outfalls onto the main roof, some of the water seemed to be finding its way under the tiles, I've temporarily fixed this gap but does anyone know of a good guide showing detailed drawings that I can use to form the end of the valley correctly. I've seem plenty of drawings showing a valley terminating in a gutter but can't seem to find anything that covers a dormer valley outfalling onto a tiled roof

Sponsored Links
Thanks Datarebal,

I appear to have a grp valley that terminates in some lead work before discharging onto the roof tiles, tiles are double roman concrete tiles
Sponsored Links
Sounds about right. Under the tiles each side of the valley,Check the edges of the lead are turned up to prevent water running side ways..
Other detailing is straightforward
not much of a turn up there....will be running over the edge in a short time once the debris builds up.
cut the valley back more bring the lea over the batten higher up allows a better turn up

is that 19 x 38 batten btw?
try it next time... im not trying to pick.. but there is a finer way
I have never worked with a proper roofer so have had to learn everything by trial and error (and a smattering of common sense). Being of multi-trade background has its limits.

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links