Verge for Slate Roof

17 Jul 2016
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United Kingdom
Hi all,

I'm looking for a bit of advice on the verge options for a slate roof. My roof has been re-roofed in SIGA slate and having become suspicious recently I have read around the subject of verge construction and there appears to be two main methods - wet bedding or dry verge capping strip. The use of clips for verge tiles seems to be an optional thing unless it's a new build.

My verge has none of the above, the slates are sat overhanging the gable end (approx 50mm of slate overhangs) and then the PVC fascia boards have been fitted and a bead of black silicone applied along the join. When I questioned the builder he said his roofer said "it is completely correct to slate over a barge board and that older properties are done like this and roofing hasn't changed much over the years".

When surveying verges locally I seem to find most slate arrangements have a pointed verge.

Comments and advice much appreciated.
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are saying that you dont have a wet verge, its just a bare edge of exposed slate? And you dont mention any undercloak? If thats the case, then its wrong, and you could have such consequencies as high winds ripping up the edge - rain ingress - & rotting laths.

As above ref a 50mm projection - its not only typical, its in best practice roofing advisory guides.
Yes, it's just a bare edge of slate - it doesn't sit on anything and just overhangs the boards. Here is a pic to show it and in fact on this area they haven't bothered with the bead of silicone. If I look at the gable end from a window inside the house I can see daylight through the slates which seems to suggest they aren't laying flat on each other along the verge. I'm really concerned about it in terms of bad weather and as you say the rain ingress.
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As things stand there's possibly not much wrong with the verge, but what else is going to happen: if anything?
Although the underlay shouldn't be peeping out like that, & the bottom slate appears to be kicking up.
It would be best for you to contact the SIGA tech dept for advice on how they expect their slates to finish at the verge - post them your photo.
In the old days, very steep slate verges were not wet pointed - your roof looks to be a not very steep about 33 - 35 degrees.

The brickwork showing in the photo below the black PVC needs pointing - it should have been done before any new roofing was fixed. Incidentally, the verge above the black PVC isn't pointed.
Thanks for the comments. It was actually the main verge above the PVC that I am concerned about. The timer showing in the foreground is a small porch above the front door and a lot lower in height (so I guess less exposed) than the main gable end. The pitch is 42 degrees from memory. It was the slates hanging over with the silicone bead that seems a bit of a shortcut when the dry verge strips are available and appear to provide a lot more security. Reading the British Standard it seems mechanical fixing is a must these days.

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