Standard way to install new felt around valley flashing on tile roof


Is there a standard in how new felt should be installed under a valley flashing on a tile roof?

My understanding is the existing valley flashing needs to be removed, new felt needs to be installed on both sides in a weaved pattern before the valley flashing is put back.

Is that pretty much the only way to properly install new felt on a existing file roof?

I have also heard argument to leave the existing felt alone, install new felt on top and leave it lying on top of the flashing. In this case, the flashing does not need to be removed, and new felt can be installed on either side independently.

Does this technique make sense? Is it acceptable?


We always Remove old valley and valley felt, then run a full roll of ice and water centered in the valley, then a layor of rosin paper on top to allow for expansion and contract, install the valley metal with slaters edge and clips, run 6" strips of shielded th he edges 3" on metal 3" on shield, then install new felt under the old felt and over the new valley metal by 3".

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What’s the reason for installing the new felt under the old one?

It sounds like the new felt lies on top of the flashing instead of underneath?


New felt under the old felt so if the tile leaks the water runs down the old felt on the new felt and into the valley. If you put the felt under the valley metal and you have a roof leak, the water will run right under the valley.