Blackjack flashing tape fail

[screwpainting]

Anyone had a problem with this stuff. I just installed a polycarbonate roof against a brick wall and used Everbuild blackjack flashing 150mm wide, with 75mm on the bricks and 75mm onto plastic. I primed the brickwork with blackjack primer as per instructions and pressed the flashing tape firmly onto this. All has been okay for about three weeks, then we just had the mother of all showers and water is getting through the tape everywhere :evil: (this has soaked all the profiled rafters and timbers beneath that I just spent three days rubbing down to bare wood and was going to prime today!!)

Really browned off and cant understand the failure, I went over the top with the prep and application (as you would) to avoid just this failure happening.

The only thing I can think of is that the bricks are old London wires and maybe the fact that there is an air space in the wire pattern indentations means that the this type of stick on tape shouldn't be used with them??. If that is so, then I will be issuing a rollicking to whoever, for not stating that this is a potential problem.

Looks like proper lead is on the menu now, I wish I'd know in the first place, I now have to clamber all over my new roof!

What a total bummer!! :evil:

 

[Rorschach]

Did you warm the tape before applying? It needs to be really soft and sticky to get a good grab, primer alone doesn't always cut it especially on surfaces like brick.

 

[screwpainting]

No, I didn't warm it but it was a very hot day, about three to four weeks ago now. But that sounds like it could be the problem, all I did was push the tape into the primed surface as hard as I could by hand.
I'd never used it before so didn't know, but it makes sense now I think about it :roll: thanks.

 

[Rorschach]

Whenever I use that kind of tape I also use a j-roller and a heat gun, warm the surface (carefully if its primed) and warm the tape too, get it into place and then using the heat gun carefull on the back I roll it with the j-roller until I can see it just start to ooze a little at the edges, then you know it has really softened and made a good bond. If you have an uneven surface then you might need to use something like the back end of a screwdriver or similar.

I recently used a bit as part of a repair to a punctured water butt, I applied heat and used a broom handle to mash it into place as access was limited.

 

[RobinBHM]

Flashband needs to be warmed so its soft and then pressed in place with a wallpaper seam roller or the big J rollers, you cant get nearly enough pressure with fingers.

150mm seems a bit small to me, thats only 75mm on the brick and 75mm on the poly.

Of course flashband is not really the best way, lead flashing cut in is the pro way.

Having said that my Fathers conservatory is flashbanded and has lasted 30 years......

 

[screwpainting]

Well I'm going for lead now guys, I was in two minds at the start... bloody nuisance though.

 

[Rorschach]

You might be able to save it, worth a try.

 

[Sheffield Tony]

I always assumed that stuff was for quick and dirty bodged repairs. Where I've used it I've since replaced it with lead done properly, which I quite enjoyed. Horrible sticky job getting it off again. White spirit does dissolve it eventually where I needed to clean off the primer.