Self adhesive flashband to corrugated roof advice sought please.

[nick]

Self adhesive flashband to corrugated roof advice sought please.

Dear All,

In a bid to make our corrugated asbestos garage roof weather proof, I bought some bituminous self adhesive 'flashband' flashing to apply to the edges of the roof where it meets a surrounding low brick parapet.

I'm quite pleased with the performance of this product as I was a little sceptical when it was suggested I use this (neighbouring lead flashing was stolen).

Application along the long edges of the roof has been fine as the flashing is applied parallel to the corrugations and forms to the contours well.

However, when it comes to the end edge I have applied it like this in cross section (apologies for the poor illustration!):

___________ - flashing vvvvvvvvvvvvvvv - corrugated roof

The flashing does not stick to the trough of the corrugation as it will not flex to this shape without causing bad creasing. It only sticks to the peaks of the corrugation.

There is therefore a void between the flashing and the trough of the corrugated roof.

Have I applied this correctly or should I have cemented a 'flat' along this edge?

Is there a product I can use to fill the void, perhaps something like 'gripfill'?

Any advice appreciated!

Many thanks!

[Andy Dingley]

Yes, the black, soft bituminous mastics. These fill a moderate gap (although they'll creep out of anything over 1/4") and they're low modulus (i.e. soft) so they cope with expansion. Screwfix, Wickes et al sell them. Look for the black stuff that's called "roof and gutter sealant" and doesn't mind being applied to wet roofs.

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember [e-mail] saying something like:

You could have done that, or just fill it in with expanding foam and remember to paint that to protect it from sunlight.

[nick]

Thanks for the suggestions.......much appreciated!

I've not used any of the expanding foam or mastics before so will go have a look in our local 'shed' and see what they have. At least if it's bituminous the flashing should stick to it.

Just wanted to check what you wise and experienced people might have done!!

Best wishes.