Shed Roof - Cut Edge Treatment

Doop

I have recently built a block built shed and used metal profile sheeting for the roof eg below link.

https://www.goodwins.ie/products/tile-effect-box-profile-sheet-3-6mtr-x-1mtr-slate-grey.html?filter_set[]=16,1814,1856

We've cut the panels to size but we now have an exposed cut edge, which I would like to treat before it becomes cut edge corrosion. Anyone know of an off the shelf product to do this?... Google brings back results of large warehouses that are already corroding this is a very small preventative job im looking at doing....

my3cents

This is one of those things you just have to try and not worry about. I have a barn covered in metal roofing and its been there at least 30 years and the edges have never been an issue.

If you really wanted to you could paint the edges with a variety of paints. Perhaps a similar colour of smooth Hammerite can be found? If so I'd mask the edge off with masking tape about half and inch back from the edge and then paint both the edge and the area masked off.

Probably best to do a test first on a scrap so you know how the Hammerite reacts with the original finish.

Another possible finish is Owtrol Oil 50/50 with any suitably matching oil based paint.

CJhaughey

Are both edges cut? If not just flip the sheet around so the cut edge is under the ridge cover.

Alun

I too have box section roofing on my shed which has been in place for over 15 years. I've just checked the exposed cut edge above the guttering and there's not even the slightest hint of rust to be seen.

Calahonda52

Looks like a solution in search of a problem

Doop

Thanks all...

Calahonda52 wrote: »

Looks like a solution in search of a problem

In reality I'm trying to prevent a problem before it occurs, cut edge corrosion being a well known defect... however if peoples experience is that it may not occur at all I guess id be happy to run the risk. Or as my3cents suggests I might check out apply hammerite or the likes.

CJhaughey wrote: »

Are both edges cut? If not just flip the sheet around so the cut edge is under the ridge cover.

Yes I had asked that the cut egde be installed under the flashing, however that didnt happen :rolleyes: its actually more of a mono pitch /lean to at an awkward angle so the panels were cut to fit, ...cant just flip them around.

I'll report back in 5 years! :pac:

studdlymurphy

I'd paint the edges the same colour as the roof for added protection. I have done this a few times and happy with results.

jack of all

I don't know if the cut edges on my small shed were painted, but they look fine after 4 years. There was some cuts/ scrapes and dings to the plastisol coating in places (due to poor handling I suppose) so I requested a tin of touch up paint from the supplier and used that to treat these damaged areas with good results- an ounce of prevention being better than a pound of cure etc. There were no details of the make up of the paint on the tin (nothing other than the colour name) but it was an enamel of some sort.

Alun

I just googled "box profile roofing cut edge corrosion" and interestingly all of the images that pop up of such corrosion are of areas where two sections are joined together, not of an exposed edge.

I wonder if the issue here is that water pools around such joints and gets drawn underneath by capillary action, and it's this prolonged exposure that causes the corrosion. Whereas in my case where the exposed edge is on a roof section that's angled it drips off easily and doesn't cause the same problem?

Lumen

Depends on salt exposure. When I was researching steel guttering people were saying that if you're near the coast the plain galvanized stuff isn't up to scratch, and to go with painted.

jack of all

Alun wrote: »

I just googled "box profile roofing cut edge corrosion" and interestingly all of the images that pop up of such corrosion are of areas where two sections are joined together, not of an exposed edge.

I wonder if the issue here is that water pools around such joints and gets drawn underneath by capillary action, and it's this prolonged exposure that causes the corrosion. Whereas in my case where the exposed edge is on a roof section that's angled it drips off easily and doesn't cause the same problem?

Could it also be down to the cutting- sheet ends (especially on insulated sheets with cut back ends) are factory cut and presumably this minimises the damage to the plastic coating and underlying zinc coated steel. Site cutting could produce more heat which damages the coating protection and zinc coating. Although water pooling has to promote corrosion if the coating is compromised already. I remember seeing a building on the west coat which had been "freshened up" with a new "Nordman" type cladding sheet- the job was only a few years old but had corroded horribly- apparently around the fixings!