GAF Grand Slate Shingle

We are having GAF Grand Slate shingles put on our house right now and from what it looks like, they are weaving the valleys which makes it look horrible since the shingles are thick. We spoke with the general contractor and he said it is because the sun hasn’t settled it yet. I would like a professional opinion. According to GAF instructions it isn’t supposed to be woven. I don’t want them to continue with the job right now and don’t feel we should have to pay for a company who isn’t properly installing them. Am I correct or do I have to pay them since they have already started? Please help. How do I attach a photo to show what it looks like?

Here is the PIC of her shingles:

Manufacturer’s installation recommendations should always be followed. In this case GAF recommends either an open valley in which metal flashing is visible down the center of the valley, or a closed valley using the “cut” method in which shingles from the first roof slope extend several feet onto the adjacent slope, and shingles from the second slope overlap shingles from the first slope and are cut off parallel to and a couple inches offset from, the valley centerline.

The manufacturer does not recommend woven valleys. After viewing the photo… I’d be very unhappy with that work.

If it were my roof, I would insist that it be installed according to the manufacturer’s recommendations. Failure to follow the manufacturer’s recommendations may well void the manufacturer’s warranty and result in future leakage.

Pictured is a “California cut” valley which looks very similar to the “Cut” valley.

Here is what she has:



I wouldn’t pay for it. I would also contact the manufacturer and have them send out a rep.

Good idea. No question about who’s right if you’re claim is being backed up by the manufacturer. Contractor’s wrong.

As a roofer, I can tell you…Don’t pay until this situation is remedied. Manufacturer’s recommendations come before corner cutting! That there is just ugly! The sun will do nothing but make it look worse.

Thank you all for all your help and information. We spoke with the contractor and he is going to have another company install them correctly at no cost to us.

When it comes to roof installation always make sure that the roofer is certified by the manufacturer as an installer of that type of product.