HMS Beagle wrote:
Thanks.
I did not use the foam gasket. I would not use any gasket in this application and the one provided is polyethylene foam which it seems to me is particularly unsuitable. If the roof was crowned enough to require something other than sealant it should be filled with something solid and shaped to the crown, then wet sealed without a gasket.
Gaskets generally work if the flange and the surface are stiff enough to retain some clamping pressure between the fasteners over the long term. The flange is certainly not stiff enough, and the roof is suspect!
John I'm so glad I found this thread. Love the detail and your description is fantastic ( no pun intended ).
Six months ago I removed my rooftop air conditioner and replaced with another Fantastic vent also. I followed the instructions and used the foam gasket and used Sikaflex 11 PU around the outer joint, which is the only seal apart from the foam under the flange.
Sure enough, it has leaked, but not real bad. No staining on the lining of the ceiling. My fiver is a small Okanagan with grey carpet on the ceiling, and a polystyrene & ply roof with TPO on the top.
I have managed to get the vent out, not real hard, but the difficult part was removing the Eternabond which I placed after I found the leak ! It's all back to square one now and I have installed new spacer timbers as the hole was a little large for the Fantastic vent. I have secured these well and they are screwed and sealed with PU adhesive.
Because the TPO roof does not cover the top of the timber spacers, I intend to place Eternabond over the TPO and timber. Strips of about 50mm should do. Then I intend to mount the Fantastic vent directly on the Eternabond, I hope that makes sense. I will use the scourer supplied with the Eternabond to roughen up the surface of the tape before I mount the vent with the PU adhesive and screws.
Can anyone see any issues that may arise before I finally fit the vent in a few days ?
Best wishes
Pat
