ᐅ How to seal the gap between a ventilation pipe and the wall after a core drill?

Hello everyone,

What is the best way to seal the gap between the wall and the ventilation duct to make it as airtight as possible? The first thing that comes to mind is foam, but then the pipes would be permanently fixed. Are there special solutions for this? Like an expanding tape that you press into the gap, or can you tape over the gap, covering both the pipe and the wall? It’s drafty through the drilling hole. You only notice it if you hold your hand directly in front of it. I assume it comes from the cavity behind the brickwork.

The back side of the drilling hole leads into our garage. There, I sealed everything with acrylic and painted over it. However, in the garage, the ventilation pipe touches the wall, so there was no gap like in the utility room.

Hello,

A compressible sealing tape can of course work if you are skillful enough. This is usually how pipe penetrations are sealed. It would also have been useful on the outside of the acrylic sealant. However, you can’t really press a compressible sealing tape into the gap; it should stick to the pipe and then expand. Alternatively, you can use a round cord that is wide enough to fill the gap well, then seal it on the inside and paint over it. You can also inject cartridge sealant into the gap and then, for aesthetic reasons, apply the round cord and acrylic joint on top and paint it.

By the way, if there is a draft, isn’t rainwater being driven in by wind-driven rain? Or what is the situation on the outside?
If so, I would recommend improving the external sealing with a compressible sealing tape.

Best regards

It looks different on the backside. I’ve attached another picture to show this. The backside is also located in our garage. The pipes run through the garage for a short distance and then go outside there. On the garage side, the foam pipe insulation ends right at the wall. The gap was temporarily filled with foam by the installer. I trimmed the foam flush and then smoothed it over with acrylic sealant, applying it by brush.

I can’t say exactly where or why there is a draft. It could either be coming through the garage or through the cavity behind the facing brick and in front of the insulation.

I have already considered using compression tape. The gap varies from 1.5cm (0.6 inches) to a few millimeters. However, the pipe can be moved slightly. Maybe I can get the tape in there. It doesn’t necessarily have to be glued on both sides. That would not be the case on the wall either, if I only stick the tape on the pipe side.

Backer rod is also a good idea. I will look into that. I probably won’t be able to get a clean result with foam anymore. That would have had to be injected during the shell construction phase.

Sorry, here is the picture.

I would loosely insert insulation wool into the gap and seal the frontmost gap with acrylic.