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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
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    We've got a decommissioned wood stove and we'll soon be having the flue removed, so the hole will need to be patched over... The same will be needed for a roof window or two we're having removed later in the year. We are supplying the slates. Our existing slates are 20" x 12".

    I've been told that ours are likely Penrhyn Heather Blue, and wondered whether you guys agree?

    Also, we went to the reclamation yard at the weekend and picked up some matching slates for the patch up work needed. I'm guessing it is hard to tell from photos, but I wondered whether anyone can tell what condition they are in? I read that they are supposed to ring when tapped; these certainly don't. But then I also read that not all old tiles will ring. I could try a short video of me tapping them with a hammer and post it to Google Drive?

    Are the size of the holes and the damage around the holes a problem?

    The reclaimed ones are also a tad larger; just by a few mm. Will that make the roofer's job more difficult or is that quite normal and expected?

    Any thoughts before the workman comes to fit them would be much appreciated.

    Many thanks

    PS - I've uploaded the photos to Google Drive as there are quite a few of them. Hope that's ok. I'm happy to upload them into the thread via the forum if that's preferred? Just let me know. Cheers.

    Slates on house:

    Reclaimed slates bought:
    • CommentAuthorArtiglio
    • CommentTimeFeb 9th 2021
    Can’t access your pictures just now. However

    A decent used slate when rapped with a knuckle (i would’nt use a hammer) doesn’t so much ring ( though i can see where that idea comes from) to me it sounds solid and “live”, a slate that is cracked, delaminated, rotten is just dull/ dead, you’ll soon know the difference when you’ve heard both.
    Avoid slates that have come from a coastal environment they often ( but not always) seem to go soft , again if you have a slate cutter you’ll soon know the difference.

    If you’re happy with the look of the match then don’t worry too much , but you might want to give the ones you’ve picked up a bit of a clean to remove any dirt they’ve accumulated over the years. I’ve recently used some reclaimed from a building in london and they were absolutely filthy and not a brilliant match at first glance but once up and with a few bouts of rain and wind are much better.

    I found some new penryn at a local yard , that had been returned as over ordered several years ago, no way i’d pay the current new price i was quoted, fortunately these were much cheaper.
    • CommentAuthorrevor
    • CommentTimeFeb 9th 2021
    They look a decent match I would not worry about size of holes the slater will make new ones if needed and any damage at that point will be covered by the slate above. Just check the overlap is the same on the 2nd hand ones as on the roof, you can tell from the weathered part to make sure the existing holes will be covered, they should be, as I think it is pretty standard at around 6.5 " Try and match the thickness of the slates if you can thickness is graded think there are 3 for Penryn otherwise they wont sit properly against adjacent slate. A proper slater as opposed to a general builder will have the skill to do a decent well matched job. Being near the coast affecting the slate is a new one on me when we stripped the old roof of our farmhouse the slate had original peg holes and new holes from a re-slating we got most of them off without breakage and they were very sound. Reckon they were original from about the 1750's. They were Penryn quarried .Did not have enough of them to reroof the house so used new Penryn ones.
    • CommentAuthorArtiglio
    • CommentTimeFeb 9th 2021
    Hi Revor, it wasn’t something that had occurred to me either, but i was having trouble finding decent secondhand slates locally and ended contacting a london dealer. He won’t even bother going to look at anything past the medway towns coast bound, apparently far too many lots he’d looked at in the past were “soft and rotten”, he’s not sure why. My mums place in wales is about a mile from the coast, some of the slates on the barn are originals ( locally called cows/ cowls or similar) they vary in size and need sorting prior to use. The barn was built in 1802 , those are still as hard as nails , but are pretty thick.
    The roof i’ve just done was built in 1907 , the slates on it weren’t new when they went on ( some had been holed 3 times)(sarking board beneath had only been nailed once) and were a bit of a mixed lot, some were pretty much as good as new , others cut like soggy hardboard others has rotted pretty much to dust. I should have paid more attention at the time and noted if the direction they faced made any difference, roof is piched at 65 degrees and has almost perfect N,E,S and West faces.
    • CommentAuthorrevor
    • CommentTimeFeb 10th 2021
    When I lived in south Manchester I had to source some 2nd hand slates for covering a hole left when taking a chimney down and they were poor quality thin soft as I recall and nowhere the quality around here ( I am only about 10 miles from the Penryn quarry) So maybe the years of soot and smog and acid rain over the century before the air was cleaned up might have had a detrimental effect on slates in the industrial towns.
    @Artiglio , @revor - thank you so much for the helpful and interesting replies.

    It's actually our stove installer who will be doing the repair. He will be installing the new stove, but whilst here taking down the old flue from another part of the house and doing the patch up. So he's not a roofer / slater, but certainly seemed happy and confident enough to do the job

    I'll give them all a clean today and sort them into different thicknesses.

    We're about 18 miles from the coast where we are. The existing slates on the roof seem fine, although I've no idea when they were put on. As for the reclaimed spares I bought, I don't have the foggiest where they came from.

    Having no experience with slate, I'm still not 100% how they should sound /"ring" when tapped. I've got nothing to compare them to so it's hard to tell. I'll see if I can find any relevant youtube videos. And I won't use a hammer any more! On the plus side, I haven't broken one yet so that's good news :)

    Posted By: Artiglio
    I found some new penryn at a local yard , that had been returned as over ordered several years ago, no way i’d pay the current new price i was quoted, fortunately these were much cheaper.

    If you don't mind me asking, what kind of price were you looking at for new ones? Just for off topic future reference as part of the house might need a re-roof at some point.

    Thanks again
    • CommentAuthorcjard
    • CommentTimeFeb 13th 2021
    @greenfinger you might need a remortgage - a few years back the local supplier wanted a tenner each
    • CommentAuthorrevor
    • CommentTimeFeb 13th 2021
    400x300 in 2011 were £1.59 in 2016 £ 2.12 and 400 x 450 £6.13 all plus VAT They were mid thickness 8mm thinner grade will be cheaper and thicker obviously more. Our slater reckoned that they were best slate to work with, imports are not as strong and break easily with a lot of waste and whilst cheaper (approx. 30%), are a false economy. I did not budget for the larger size which are needed around roof windows and valleys to avoid "bits" and needed a lot of them. If you want a good idea of current price don't look on the internet those I think are silly prices but ring a local builders merchant in N Wales like Huws Gray or C.L. Jones.
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