Can metal trims be used with GRP roof?

[BartW]

HI,

Namely, as per the top line. These and similar:

 

 

https://www.ultra-flex.com/trims/

 

 

https://www.roofingsuperstore.co.uk/product/ryno-f4-grp-roof-edge-trim-100mm-x-60mm-x-3000mm-black.html?gclid=Cj0KCQjwr4eYBhDrARIsANPywCiWbttvk1z3JWdhnlxmbqZSkfkb5SRJmNuP1rnMaJW7ZzZeaxJfcwYaAiBYEALw_wcB

 

Would they bond well with GRP, or would their expansion rate be a possible cause of delamination?

 

Trying to detail our roofs and standard trims I find a bit bulky.

 

Thanks!

 

Bart

Edited August 21, 2022 by BartW

[markc]

Aluminium trims can be bonded with grp and on fairly short runs will be fine, on long runs you could well find the trims distorting with heat expansion where the grp trims are pretty stable over a very wide temp range

[BartW]

Just now, markc said:

Aluminium trims can be bonded with grp and on fairly short runs will be fine, on long runs you could well find the trims distorting with heat expansion where the grp trims are pretty stable over a very wide temp range

 

Thanks!

 

I will have up to 6m runs, and last thing I want is the aluminium trim spiralling out of shape.

 

So, stick to GRP trims I guess, and the one as per the latter link should be fine to use? Seeing that it is made out of GRP.

 

[SteamyTea]

14 minutes ago, BartW said:

Would they bond well with GRP, or would their expansion rate be a possible cause of delamination?

Generally alright if prepped correctly.

While expandion differential is possible, I have never noticed it in practice.

GRP is 25x10^-6m.m^-1.K^-1

Aluminium 21 to 24x10^-6m.m^-1.K^-1

Steal 11 to 13x10^-6m.m^-1.K^-1

All very small movements over a few metres and if bonded to each other, tend to take the median value.