Roofing Slate Roof Repair, slate, valley

Roofing Slate Roof Repair, slate, valley


Roof repair


I’d like to get your opinion on a roof repair of my residential home. I recently hired a licensed roofer to repair the slate valley. The problem was a leak in this area. The roofer was to tear the existing slate, install a water shield, re-install slate tiles and replace those that couldn’t be saved, and install a new leader. Unfortunately I had to leave for work early that day and wasn’t able to check the work.

I am not a roofer, but to my eyes the job seems very sloppy. The main issues I see are:

There were two large holes on either side where the valley meets the funnel outlet. They just filled these in with large amounts of silicone.

Pieces of the shielding(not sure if old or new) are sticking out into the valley.

The slates are not straight in the valley edge.

Many of the slates are not sitting flat and overlap. As a consequence there are gaps on the bottom of the slates. Some lie flat while others overlap. The gaps can be up to 1/4-1/2 inch.

I’m also concerned with some of the metal tabs that hold the slates are sticking out and wonder if those slates should have also been screwed in as well.

I gave a deposit but have not paid the full amount yet. I have told them that wasn’t happy with the job and am waiting to hear back. As mentioned, I’d like to get your opinion, and suggestions on how to proceed. Please see image(s) attached.

Thank you in advance,



I cant see much from the picture you attached.

I’ll address these in order:

Large holes packed with silicone: if it wasn’t there before why is it there now? Sometimes when the installer isn’t familiar with proper standards they will resort to the "roof in a tube" method. Proper mechanical flashing with a non corroding sheet metal such as copper or stainless steel should be used at edges and transitions where the slate doesn’t cover, not a baseball size wad of caulk.

When done properly an entire slate roof can be done with only a teaspoon of sealant in one or two non critical areas, not blobs of the stuff in high volume areas like a valley or eave.

Ice and Water Shield sticking out in the valley: This material should be under the valley; not on top of it; unless the existing valley (metal) wasn’t replaced. Either way the underlayment should at least be trimmed back so its out of sight.

Slates not straight in the valley: There is pretty much no excuse for this one; each slate should be held in position, marked and then brought down to the ground to be cut. What probably happened here is that in reinstalling the saved cut slates they got out of order; then they wound up putting slates in that didn’t quite line up because they are no longer in their original position. I’m sure you have another original valley on the house, ask why the repaired valley doesn’t look the same.

Over and underlap with gaps: Same as above; slates not put back in their original position so they don’t quite match up any more. High grade domestic slate cost anywhere between $1.75 to $4.50 per piece, they may have been trying to stay within a budget on the repair by using as many of the saved slates as possible.

Metal tabs holding slates sticking out: This is a common mistake, slates that are being installed in the middle of a field of existing slates have no way to be fastened. The only way to do it is to use a slate hook; I see lots of repairs done with 1" wide strips of copper sheet, folded up around the bottom of the slate holding it in position. This is a problem when snow and ice slide across the roof; the sliding snow straightens the copper tab and the slate slides right out along with the snow and ice. The rule is if you are able to bend it by hand the ice can do it too; most good roofing supply houses carry stainless steel slate hooks, they are about the gauge of chain link fence and cannot be bent by hand or snow and therefore will remain in place for the remaining life of the roof.

I suspect if you aren’t happy with the roof repair the owner of the roofing company wont be either. Show him the problems and other areas where the roof looks correct, ask why yours no longer looks that way. I’m positive he will make it right.

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