I don't think that Metalex is anything that it used to be. So I don't know what is a replacement for it any more. Metalex was bright Green & Copper based ( though there was a clear version ) but now it looks weak & I think it's Zinc based. And it's got sediment in it and while the real Metalex was expensive, the new stuff is exorbitantly priced.
I'd probably just make a saturated solution of water & Copper sulphate & soak that in myself ( not suggesting that it would work though )
martin11,
Dec 24, 6:55pm
Put an eaves flashing in . Have a look in the roofing codes and you will see what I mean .
martin11,
Dec 24, 6:56pm
45 deg purlins ,never heard of the crazy ideal the roofing nails or screws would look horrible for the new roofing .
mechnificent,
Dec 24, 7:06pm
Ha. it all sound nutty to me. you gotta have air circulation.
apollo11,
Dec 24, 7:33pm
I have done. It seems to be working fine.
tweake,
Dec 24, 8:11pm
depends on the roofing. you can use that profile that uses hidden clips. no nail patter nto be seen.
tweake,
Dec 24, 8:22pm
thats why its done. air gap under the roofing for condensation purposes. thats how it should be done. previous person has done it almost correctly. there should be drainage around the newer purlins. so if the roof leaks water can run down inside the air gap and out the bottom. it should also have insect mesh across the bottom.
there is purlins with drainage built in available somewhere. i have seen it advertised in nz.
vented batten. fit those instead of the top wooden purlin.
apollo11,
Dec 24, 8:37pm
Cheers. It's just a standard coloursteel ridge cap. There is no insect mesh, is this to keep out wasps?
tweake,
Dec 24, 8:42pm
the ridge cap should be vented. you want air circulation between the sarking and iron. water should drain down and out, and air flow up and out. insect mesh to keep out wasps/bees etc
apollo11,
Dec 24, 8:52pm
The vented battens look good, we will give them a go if we decide to re-roof. Thanks for the advice.
martin11,
Dec 24, 9:31pm
Show me where in the Code for Roofing that is true ?
bergkamp,
Dec 24, 9:51pm
this is just so wrong on so many levels .
his roof is about to blow off (purlins connected only to 10mm sarking) huge gaps to eaves and barge and you state "this person has done it correctly "! unbelievable .
its an assumption to think the doubling up has been done for ventilation ,there is usually plenty of ventilation in an 80yr old 28 degree pitch roof
vented ridge capping etcetc definately has its place but its wrong to say it applies to every roof
tweake,
Dec 24, 10:05pm
i did not state "this person has done it correctly ". i also never said vented ridge cap applies to every roof.
please try to read before commenting.
tweake,
Dec 24, 10:24pm
but its not a standard roof. its basically a sheathed roof. sarking may leak a ton of ventilation through it, but it has underlay on it which reduces air flow, basically (probably poorly) separating the roof from the ceiling space. as its a sheathed roof its not dried by the ceiling air flow. hence the need for drying airflow between iron and sheathing.
martin11,
Dec 24, 10:40pm
The old 6x1/2 native sarking on the roof would have many gaps between the boards and probaply splits it the boards to allow air movement .
apollo11,
Dec 24, 10:48pm
This is what our roof has.
Rafters - Old purlins - 10mm sarking - old building paper - newer purlins - newer building paper - corrugated iron.
So it's a separate envelope as far as ventilation goes.
tweake,
Dec 24, 11:13pm
as mentioned above (and by me in the post you quoted) it has building paper/underlay on the sarking which reduces airflow.
bergkamp,
Dec 25, 12:30am
anyway , i've rung around and framesaver is perfect , they have even tested it on building papers . it may bring the timber up to h1.2 , internal enviroment
apollo11,
Dec 25, 12:38am
Our house is 90 years old, all rough sawn rimu. Very little borer in the place except where the wood has stayed damp- ie where it sits on concrete ring foundation etc. All replaced with H4 now. I don't think borer like dry wood. Have you seen areas of borer on your sarking/purlins?
bergkamp,
Dec 25, 12:52am
agreed , borer dont like the heat , and i too have replaced a bit of the subfloor with h4 and sprayed the entire subfloor
the reason i want to use the presevative is purely for future proofing , so easy to do with the roof off
apollo11,
Dec 25, 1:02am
I'd love to do what you are doing at a later date, but ours is an old house. It's held together with a bunch of rusty 100mm nails. None of the ties, brackets and straps that the house being built next door is packed full of. We have new foundations/ anchor piles etc but the rest of the house is state of the art 1930's construction technique.
bergkamp,
Dec 25, 3:14am
yup i hear ya , ours is 1930s too .
i'm also putting in a purlin screw and (if access is OK ) a cpc 40 to rafter/top plate and collar ties . but i see it not so much as a house but a home
Since the public registrations are closed, you must have an invite from a current member to be able to register and post in this thread.
Have an account? Login here.