Dry Verges

[Chris J Dixon]

There seems to be a move to retro-fit plastic dry verges these days, with plenty of firms touting for business.

My cement tiled roof is due for some attention, and I don't do aerial clambering.

Are they a good idea? What are they screwed into?

What sort of prices are reasonable? I am in a semi, but next door is lower, so I effectively have two gable ends.

Unusually for me, I was curious enough to allow a caller at my door to give me a price, which started at £550, then dropped by £100. I've just had a flyer for another outfit (devoid of street address) which would be £298.

What dodges do the unscrupulous use, about which I should be wary?

Chris

[Reentrant]

I think they screw to the fascia. They look awful though - retrofit ones in particular. Mortar always cracks after a few years - I guess it can't cope with the movement caused by thermal expansion/contraction of the different materials. I'm surprised no-one seems to have come up with a permanent, UV-proof, flexible (and cheap) alternative filler to cement-based mortar.

[harry]

There's lots of different sorts. Just Google. Some is nailed on to the existing verge, some is nailed on to the top of th e edge rafter. Main advantage is in windy situations sops tile from blowing off too easily .

[Andrew]

Technically they are nonsense. A properly mortared end joint using the correct amount of cement for bedding will last the life of the property.

what is more important is the way the tiles and undercloak are installed.

Small tiles need a hip effect at the end to stop water being blown over the gable end and causing rot to the ends of the tile battens and supports.

large concrete tiles like Marley Modern must be laid flat and so the undercloak must tilt down about 3 degrees so that water blown over the gable end runs down the outer edge and not find its way back into and behind the barge boards.

Ask about 20 'roofers' how they install Marley Modern tiles and you'll by lucky if even one knows the correct answer. You should therefore assume that most of the people installing dry verges, also haven't bothered to RTFM. A solidly mortared verge is probably your best bet if you live in an exposed area. In Southern Ireland it is standard practice to build some shuttering along the end of the roof from ridge down to gutter, infill with some chicken wire and create a solid concrete slab about 8 inches wide and 4 inches deep to stop extreme winds ripping the whole roof off.

Dry ridges and verges are used by the big builders because it is quicker and looks tidy.

The storm we had in October 2013 ripped a few of these plastic end panels off on a few houses where I live.

[www.GymRatZ.co.uk]

They're screwed into the ends of the roofing battens.

We've had anthracite (colour) cement tiles (look like thick slates) on the extention and the plastic dry-verge of the same colour looks spot-on.

The best thing about them is where cloaked(?) tiles aren't available which they weren't for our tiles is they get rid of the need to have the tiles mortar-fixed but.... as a retro-fit item on an old roof, the mortar-fixed perimeter concrete tiles won't be nail-fixed as I believe is the requirement for current roofing standards so I'd be wary of the fact that a) Your tiles won't be drilled for nail (mechanical fixing) b) They'll be removing the only form of secure tile fixing on the leading edge of the tiles.

Yes the dry-verge should prevent the wind from catching the tiles and ripping the whole lot off but I'd want more than a bit of plastic and 1 screw doing this job especially in a windy location.

The following might help: klober.co.uk/media/uploads/56fd46cb14bbf.pdf

[Harry Bloomfield]

Mortar, done properly will last for decades. That is how ours was done

70 years ago, using quite a poor mix, but it lasted until 15 years ago. Then I replaced it with a better mix.

I used two lengths of angle iron as a former, welded together, one laid on the tiles, the second to touch the wall and just filled up in between. I waited until the mortar was near set, then slide it up the roof, to do the next section. There is no signs of movement or cracking anywhere - the mortar will move with the wall, the tiles move with the wall and mortar expansion, so why would it crack?

Getting back to the original question, scaffold hire will take care of much of those quotes, which suggests they will be working off ladders. It is not the sort of job that can be done properly from ladder, so they must be skimping somewhere. I suspect in the quality of the workmanship - expect them to blow away in the first gale.

[GB]

Am I the only one who read the subject line and thought "lube"?

[www.GymRatZ.co.uk]

No... I had to re-read it too. :)

[Jim GM4DHJ ...]

stick to Tifting ....

[Syd Rumpo]

I wanted your soft verges But you gave me the hard shoulder.

(Adrian Henri)

Cheers