Priming Corrugated Barn Roof - Advice Needed

Bluscreendream

Hi folks,

Just looking for some advise on how I should go about priming this particular surface on my barn roof. The sheets were put up in the mid 90s and so are the more heavy gauge metal. The original oxide coating is peeling and flaking off so I've sanded the whole lot down best I could, (please see some photos attached). As you can see I've gotten back to the bare metal on some parts but there is a good but of old paint on it which was also sanded back a good bit. Could anyone advise on a type of primer that would adhere well on this mix of bare metal and paint so that I could then apply a standard red oxide finish on top? Cheers.

roof03.jpg

roof02.jpg

roof01.jpg

enricoh

I thought red oxide straight onto that was the done thing? I'd email that to castle paints and ask them what they recommend and the size of the shed.

Bluscreendream

https://www.boards.ie/discussion/comment/117716992#Comment_117716992

It wouldn't be advised, for example if you're going to paint onto new galvanised sheets you need to apply an etch primer but my situation is slightly trickier 😞

Good loser

Bluescreen how did you sand it to the condition shown?

wrangler

https://www.boards.ie/discussion/comment/117717087#Comment_117717087

I use a powerwasher here to prepare and ordinary oxide paint on roofs, I've used primer befoore painting on some galvanised troughs, and to be honest, using the primer doesn't seem to make any difference. the galvanise still lifts the paint

Good loser

https://www.boards.ie/discussion/comment/117725901#Comment_117725901

To paint a reasonably flat roof would you use a short brush (how wide?) or a standing up long handled brush using a tray?

Is it possible to get one with corrugations?

wrangler

https://www.boards.ie/discussion/comment/117731029#Comment_117731029

I'd usually get a contractor to spray roofs, I've seen corrugated roller . Castle Paints in Tullamore should have them .and they're good for advice. They sell good paint, we've used it for years here.

Here's a link and you'll see the corrugated roller at the bottom, Their primer is there too but I didn't find It successful on sheep feeders.

https://www.castlepaints.ie/black-oxide-paint

i've a neighbour that claims to use a sweeping brush and his roofs look alright.

Bluscreendream

https://www.boards.ie/discussion/comment/117725857#Comment_117725857

I used a standard angle grinder with a 3" wire cup brush wheel, after that I would do a single pass with P40 Grit sandpaper over the the same section to catch any other untouched parts. A very soul destroying and testing experience on a large roof, not for the faint hearted 🙂

Bluscreendream

https://www.boards.ie/discussion/comment/117725901#Comment_117725901

In 2018 I did a shed with brand new galvanised sheets, I applied an etch primer from Caste Paints and then fisnished with the standard red oxide you see in all the agri stores. The roof is perfect, no paint lifting yet. I'm no expert but from reading various boards it seems to be down to choosing the right type of primer for the surface in question.

enricoh

Sounds like a lot of work to me, would you not just buy red cladding sheets?

I've a shed up 20 years and never looked at the sheeting, and I better not have to for another 20!

J.O. Farmer

https://www.boards.ie/discussion/comment/117731464#Comment_117731464

A good soft sweeping brush is the one to use. You'll probably pick one up for a fiver and dump it after.

SGM978

well folks,

I’m replacing old sheets of corrugated tin on an old shed. On the left hand side you can see the new sheets I’ve put down but I’ve ran into trouble now here because the slots of the new sheets ( which are 42inches wide) won’t sit in correctly with the old sheets (which are 30 inches wide ). There is enough of an overlap but the slots won’t meet up.

Bit worried now what to do! Any help from Roofers appreciated.