Jesus, go away you pest, . so your a qualified plumber now, FM. tell us everything you know about roofing and flashing . we'll give you 12.778 nano seconds to reply, . that'll be plenty
gpg58,
Jun 1, 12:16pm
I have lead flashing around a chimney here, and have replaced iron with zinculme. Total disaster, rust holes thru iron and a water leak within 3 - 4 years, (under the lead), so like it or not, golfdiver is absolutely correct on that. I have now wire brushed, patched, primed and painted as temporary fix, but intend to replace lead next summer.
martin11,
Jun 1, 12:59pm
This is correct . Lead will react with zincalume and cause problems .
trade4us2,
Jun 1, 1:28pm
It looks like zincalume is the problem. I have never had it on my houses. Zincalume was used on a new build, and the spouting rusted out in a few years. I am quite happy with galvanised steel, which is up to 100 years old on my house. And the black Butynol is also fine. I don't walk on the Butynol.
golfdiver,
Jun 1, 1:29pm
Given that ridge/hip flashings come in a maximum of 8 metres. Please tell us how you are going to seal the joints on a 25 metre long ridge? There are some top quality sealants out there now, and they are lasting very well between metal layers. Your comment that sealants are a temporary solution and a lazy man’s fix just shows your ignorance.
golfdiver,
Jun 1, 1:32pm
Lol, if you get a plumber for this problem, you will keep having issues. It’s a roofing problem you have. Pretty sure we will be too busy to assist you though.
golfdiver,
Jun 1, 1:35pm
Zincalume is a terrific product for resisting corrosion, but don’t have black butynol in contact with it. I could show you photos that would terrify you. What kind of spouting was it?
martin11,
Jun 1, 1:47pm
The sealant in that case is protected from the UV but the Expansion and Contraction will eventually crank the sealant and moisture may get in depending upon the amount of lap between sections .
Sealant use on builds in the last 30 years have been a major cause of water getting into houses ,particularly around windows and soffits . Thats why the building codes changed back to having to put some form of flashing in .
golfdiver,
Jun 1, 1:56pm
How were you going to seal that lap again?
martin11,
Jun 1, 2:07pm
With lengths such as 25m in 3 sections when they were done years ago before sealant were used the roof had enough pitch on the iron and the lap was long enough on the ridging to stop any water getting in also the laps were done in consideration which way the prevailing wet weather wind came from .
golfdiver,
Jun 1, 2:23pm
They usually had a lead cover over the join. But now lead can’t be used, so how would you do it without sealant? And while we are at it, how would you waterproof a flue penetration on longrun or a toilet vent pipe without using sealant?
golfdiver,
Jun 1, 2:25pm
Actually I just had a look at your mansion. Dead simple to waterproof those junctions. But before I tell you, what does it say on the plan the council permitted?
martin11,
Jun 1, 2:35pm
I started in 1969 in the building industry and on long straight runs we have never used lead but on the intersection of the hips /ridge we did ,nowadays you can get sheet alloy flashing material to do the same job but its expensive , so people use the cheaper method sealants
trade4us2,
Jun 1, 2:41pm
The zincalume spouting was just the usual common shape. It went completely rusty. We threw it all out and installed plastic spouting that is excellent. The roof was zincalume also. I hope that is all right. The roofing contractor was one of the largest in Auckland, and did a bad job. He ran the building paper up and down, instead of across. The reason why that is wrong should be obvious. I used the same company to put Butynol on my house. That seems to be OK except that he knew there were nail heads sticking up, and he just ran the Butynol over the top of them. I shall never use that company again, or zincalume.
Was the gutter unpainted zincalume? What moron put the ply down for the butynol with nails? It must always be screwed. What pitch was the zincalume roof ? What do you think the purpose of underlay is?
golfdiver,
Jun 1, 4:27pm
Actually we now have to use a stick on membrane tape under mitres. It’s largely a waste of time as when the drill penetrates it for the mitre rivets the integrity is lost. It keeps specifiers happy though. The pre-molded ones are useless. They only suit a pitch of around 20 degrees and don’t come coloured. They are for amateurs.
tegretol,
Jun 1, 4:44pm
Mmmm you are correct. Looks like I may need to replace the ridge-caps as well. Been up and had a look but can't see any obvious corrosion yet so the sooner the better.
gpg58,
Jun 1, 5:14pm
Perhaps just paint or coat contact area will suffice? Peel lead up and coat underside as well as top perhaps.
golfdiver,
Jun 1, 6:13pm
Or just replace them with compatible materials. Easy enough
golfdiver,
Jun 4, 9:08am
OP, why aren’t you simply following what the plan says? After all it’s a new build, albeit at least a decade to get to roofing time.
krames,
Jun 4, 10:09am
so lead onto galv is ok? lead on to zincaclume is no go? Bute onto zinc is no go Bute onto galv is ok. zinc on to galv is no go galv onto zinc is ok ?
golfdiver,
Jun 4, 11:00am
You can sidelap Galv and zincalume without concern. Obviously protective coatings whether factory or manual will greatly assist corrosion resistance. Zincalume is self sealing on cut edges so shouldn’t leach much at all in theory. Grey butynol is ok, but then again check if the glue is compatible
golfdiver,
Jun 6, 2:10pm
How’s it going with the flashing OP? What did the council inspector advise?
golfdiver,
Jun 8, 7:10pm
OP seems to have gone very quiet. I wonder why?
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