ᐅ Foam sealant for sealing gas pipes / wall penetrations?

Please don’t be harsh. I was also a bit cautious when the civil engineer from the utility companies suggested this to us, and since I couldn’t find a single discussion about well foam in this forum, I’m starting a thread on this topic.

We are currently in contact with the civil engineering company responsible for installing all the house connections for our utilities. During the on-site meeting, we expressed our wish for a multiservice sleeve (one opening with four inlets).

The construction manager informed us that they don’t install those. If something breaks, the entire part would always have to be replaced. The alternative would be four Doyma seals (costing almost €1000).

He then explained that they usually only use mortar, and this wouldn’t work for the transition to our precast concrete basement wall with subsequent 12mm (0.5 inch) perimeter insulation because the mortar wouldn’t bond with the wall. His suggestion: the company would simply run the pipes through the wall, and we would seal the holes ourselves with well foam. According to him, this is tight, sticky, so no voids form, and it is an inexpensive and good solution. He said you simply fill the four holes completely from the inside basement wall to the end of the insulation on the outside, and that you could also glue the insulation in place with it—making it a good system overall.

I’m rather skeptical. Does anyone have experience with this? Is it really airtight, or will it cause the wall around the holes to degrade? Or is this shoddy work where he’s just shifting responsibility for a proper wall penetration onto us?

Curious regards from
tabaluga

I would still try the multi-utility connection again – it is also significantly cheaper (for us, the purchase price was 231.74 €). Neighbors have used PVC pipes for the installation (or had it done), but there were problems with sealing, and the basement ended up flooded at one point (after plaster, screed, etc.).

We also have a multi-utility house connection, but on the advice of our basement builder, we filled and sealed the gaps in the externally glued insulation with expanding foam.

So far, everything is perfectly sealed.

However, caution is necessary during application — when purchasing the expanding foam at the hardware store, we first received a detailed explanation about the hazards, toxicity, and disposal requirements of the leftover material before they retrieved the requested can of foam from a locked cabinet.

Special gloves and a respirator mask were also provided.

Regards,
Dirk

Anyway... in cases like using well foam on a new build, it is better to avoid it... I would recommend the Doyma seals.

You can also purchase these yourself if the high price is discouraging.