roof valley

[Newby2]

Back in Jan. 2014, following the long stormy weather, I noticed that the felt along the 2 valleys (felt on the edge of the valley rafter) in the loft is wet. Our neighbour recommended a roofer who had a look and said the rain got in via the cracks in mortar (he said the cracks are inevitable due to movement etc.) in severe weathers. The felt is ok. From outside the fiberglass valley looks ok too. He asked me to wait until summer and contact him again so he can apply some sort of (flexible) sealant to seal the cracks.

I have been monitoring it for the past 5 months, especially after heavy rains. The felt is dry. So it seems rain only get through from the cracks in extreme weathers (e.g. strong winds and rain). Do you think sealing the valley (per the roofer's advice) would help or I can just leave it for now as severe weather like we had last winter is rare (since under normal weather the felt is dry)?

Thanks!

 

[ree]

How was your attention first drawn to this situation?

Once the pointing mortar on a valley has moved or is cracked, the difficulties dont go away - even with periods of respite. Perhaps strong winds lifted the tiles/slates?

Perhaps there's a fault built into the detailing from day one?

My limited experience has been that once the pointing has "gone" the mortar needs cleaning out and re-pointing. Once the bond between the mortar and the tile, or the valley, is broken no amount of "sealant" will repair.

Any remedial work also has to be balanced against careless people clambering about your roof. But in terms of cost you've little to lose by trying the sealant for a winter or two.