Sealing a corrugated iron roof

[Matty F]

Perhaps those in the UK don't use or know much about corrugated iron (=steel) roofing. It's widely used here in NZ. It's very strong and and cheap and holds the house together in an earthquake or hurricane. You can walk all over it without falling through.

However, I have a professionally installed corrugated iron roof. The installers don't seem to bother blocking off the holes under the lower edge, so the wind can whistle through, and rats and mice can get in. They do use building paper, but that's no problem for the rats.

What are they supposed to do instead to block the gaps? I'm about to push chicken wire into the gaps and use expanding foam.

[Andy Burns]

it's the wrong side of the world!

[Matty F]

Yes we have Eaves Fillers here. Last time I looked they cost many times the price of those. However I have never seen a roofing contractor use them.

[David WE Roberts]

We do have the occasional bit of corrugated iron around here - I've just put a tin roof on my shed (plastic covered and a different profile) and corrugated iron is widely used in agricultural buildings. As is asbestos sheeting, but that's another story.

I would normally expect some ventilation under the roof - assuming that there is insulation and a ceiling beneath - otherwise you get condensation. However I would also expect it to be bird and insect proof.

Chicken wire and foam sounds as though it would work.

HTH

Dave R

[NT]

foam strips or cement mortar

[Andy Dingley]

Haven't seen new traditional "corrrugated iron" in years. It's not used much at retail or DIY level, farms use large-section trapezoidal box with a factory plastic coating, retail parks and cheap warehouses use the small-section trapezoidal section that's put through a crimper to curve it rather than rolling it.

White PE foam filler strips are pretty universal these days.

Use paper, not wire. Unless you're rat-proofing too, in which case, use both. Foam's not cheap when you're using it in this quantity and it's worth limiting the squirt-through.

My several roofs are mostly large or small corrugation asbestos and old enough that they were sealed with mortar or nothing, both of which have since fallen out. I've a lot of squirty holding things together now. My big tin shed ('80s new build) had foam fillers from new.