Flashing a polycarbonate roof against a brick wall

[Russ42]

I have just completed roofing the pergola with polycarbonate and now need to flash the high side against a brick wall. Do I need to cut a channel into a mortar line and sit the polycarbonate flashing into this channel and water proof with silicon?

1. is there an alternative to channeling the wall

2. is silicon the best sealant for this job? Which silicon/product for this external application?

3. what should I do if the poly flashing doesn't line up with a mortar line?

[Russ42]

I think I have my answer after chatting to a very helpful Suntuf person. Since the Suntuf flashings only come in clear (I don't want the screws to feature) she suggested Zincalum with the same corrugated profile. I think, instead os cutting this into the brickwork, I will use an aluminium profile to sandwich the zincalum to the wall with a suitable adhesive between. 

If anyone has a better idea, please let me know. I am off to B to get what I need and will be doing it when I get back.

[StevieB]

Welcome to the Bunnings Workshop community @Russ42. It's great to have you join us, and thanks for reaching out to the community with your questions. 

Fantastic to hear that you've received helpful advice for this project already. Our resident D.I.Y. expert @MitchellMc would be happy to assist you with your project, but he'll be back on the site on Friday and it sounds like you'll be finished before then. Let me ask if @redracer01 might be able to share any thoughts.

We'd love to see your pergola and offer ideas and advice for upcoming projects. Please feel free to share any time.

Stevie

[Russ42]

Actually, Stevie, the helpful advice was from me. After talking to the Special Orders Desk I have found a floor in my solution. Lysaght, apparently, don't do a flashing with a corrugated profile. They do, at least, do coloured flashings. The Suntuf clear flashing must have the channel to work and the clear polycarbonate will not cover the screws which will be rusty in no time. Also the clear Suntuf can be painted, but will require an undercoat, so can't be painted underneath. I am going to ring around and try to get a Colourbond-like product which has the profile and the colour I need so I don't have to reinvent the wheel.

[MitchellMc]

Hi @Russ42,

How are you going with your project?

I might need to see a diagram to understand how your sheeting meets the wall and also how you intend to add the flashing to it. If you can't find a profiled flashing to suit, you can use a flat profile and stop water blow-back up under it with corrugated foam infill strips. The strips can sit above the roofing and be sandwiched by the flashing above. The flashing would be directly attached to the wall with Sikaflex 11FC and mechanical fixings.

I look forward to seeing a diagram or images and providing further assistance.

Mitchell

[redracer01]

Hello @Russ42 

Just to add to the suggestions made by @MitchellMc I recommend Selleys roof and gutter sealer for excellent waterproofing for the flashing. If you are still worried about the flashing bonding to the brick wall you could use Consolidated Alloys 75mm x 10m Weatherproof Byute Flash Flashing Tape. It comes in assorted sizes and lengths and almost assumes any shape you might need it for. Mind you this is practical waterproofing and might not be as pretty as you might like it. It will however provide a superior seal against inclement weather. Oh and before I forget there will be no need for you to create a channel for these products as they attach to almost any surface.

Cheers,

Red

[Russ42]

Thanks Mitchell. I can't attach the flashing far enough down the roof to hold it down with the foam underneath it as the top perlin (?) is right on the wall (is 45mm thick). I agree with the Sikaflex and I intend using the flyscreen profile Bunning has with a screw and plug into the mortar line. I will have to use a smaller flashing so it doesn't flap around in the breeze....which means: I have kind of thought I could Sikaflex a shaped bit of something at the end of each of the Suntuf's valleys up at the end under the flashing.  

[Russ42]

Thanks Red. Would the "Weatherproof Byte Flashing Tape" stick to the flat wall (I will have to Silicone/Sikaflex up the vertical mortar joints) and hold in the valleys of the Suntuf? I could then paint the zincalum flashing and lay it over the top....

[MitchellMc]

Your flashing need only extend out onto the roof the width of the infill strip @Russ42. Since the infill strip is only about 20mm wide, you could use rigid Metal Mate 32 x 25 x 3.0mm 1m Aluminium Unequal Angle. Mount the 25mm wide side to the wall, and the other side will extend out 32mm over the roofing. Before fixing it to the wall, sandwich the foam strip in between it and the roofing.

Mitchell

[Russ42]

Makes sense, thanks Mitchell. I can't see a problem with that at all. Excellent! I will see what stainless steel B has to do the job. We are close to the beach.