Seal pipe installation from basement with pressure-treated wood?

[frökenfräken]

How do we best seal a pipe installation? It concerns the piping of heating pipes that go from the basement up to the hall inside a closet and then up through the ceiling/floor to the upper floor. Unfortunately, the basement has wood treated with wood preservatives and we have a strong chemical smell of chloranisoles in and around this closet.

Apart from the small basement part, there is a crawl space, also with wood treated with preservatives. We have covered the foundation with plastic and installed a sorption dehumidifier and a negative pressure fan (Corrventa). However, the basement part is not connected to the negative pressure fan. After this measure, the odor in the house has decreased, except in and around the pipe installation.

How do we best seal the pipe installation? Can we use foam sealant, or are there better alternatives? We are aware that the best solution would be to replace all the wood treated with preservatives, but this is unfortunately not possible (financially) at the moment.
Thanks in advance!

 

[Oldboy]

Well, expanding foam often seems to be a quick and easy "solution" that doesn't require time, knowledge, or craftsmanship, but unfortunately, it is often a short-lived shortcut. Anyone trying to perform maintenance or repairs where expanding foam has been sprayed curses the person who previously did it. For health and environmental reasons, anything related to plastic and chemicals is a hassle. Which, of course, you are well aware of considering the old pressure-treated wood in the house.

Anyway, with that said, a temporary "solution" could be expanding foam. However, it is generally not advisable to use plastic near warm areas, such as a heating pipe in an older house. Probably, rather warm radiator water is needed during the winter. Heat and UV radiation (daylight) are the two factors that age plastic the fastest. Specifically, in a pipe penetration in a closet, there is hardly any direct mechanical abrasion or strain, but both wood and heating pipes move with the seasons, moisture, and heat, which can cause brittle aged plastic to crack/pulverize and thus allow air/odor from the basement to rise.

Tightly packed oakum holds up better but requires solid materials around the pipe, which a joist space might not have. It can be supplemented with a cut piece of construction plastic that is carefully taped to the pipe and floor. Naturally, this also works if expanding foam has been used.

 

[frökenfräken]

Well, construction foam often appears to be a quick and easy "solution" that doesn't require time, knowledge, or craftsmanship, but unfortunately, it's often a short-lived shortcut. Everyone who attempts maintenance or repairs where construction foam has been sprayed curses the person who did it earlier. For health and environmental reasons, anything concerning plastic and chemicals is a nuisance. Which you are naturally well aware of considering the old pressure-treated timber in the house.

That said, a temporary "solution" can be construction foam.
However, it's generally not good to use plastic near warm areas, such as a heating pipe in an older house. You'll likely need fairly warm radiator water during the winter. Heat and UV radiation (daylight) are the two factors that age plastic the fastest. In a pipe penetration in a closet, there's hardly any direct mechanical wear or stress, but both wood and heating pipes move with seasons, moisture, and heat, which can cause brittle aged plastic to crack/pulverize and thus provide openings for air/smell from the basement to rise.

Tightly packed lindrev holds up better but requires solid materials around the pipe, which a trossbotten might not have. It can be complemented with a cut piece of construction plastic that is carefully taped to the pipe and floor. Naturally, this also works if construction foam has been used.

Thank you so much for the response! It's actually a craftsman who suggested foam sealant, but I'm hesitant, hence the question. I looked more closely at the pipes now, and there are 6 pipes, all covered with (what I believe) PE-X empty tubes. Two are blue and four are gray, the gray ones seem to be these: https://www.rinkabyror.se/artikel/lk-tomror-25x20mm-50m/ It says LK Systems xxx on them and some numbers. I felt the pipes, meaning the plastic, and it feels lukewarm, so I'm not sure if there's a risk of it getting too hot. But the important thing is to make it as tight as possible since chloranisoles smell strong, and a very small amount is required for it to smell.

Based on this, is tightly packed lindrev, according to the description, still recommended? Good idea to complement with construction plastic. I think it needs to be sealed both in the basement and at the bottom of the closet, and possibly also in the ceiling of the closet because there's a certain smell in the room above it.

 

[Oldboy]

6 pipes (plastic pipes) LK systems sounds like underfloor heating?
If so, it won't get as warm. Underfloor heating in an old moderately insulated house maybe +30C(?) whereas wood, oil, or electric boilers from the 70s or older often have small radiators that can circulate radiator water up to +80C (in the depths of winter).

With a six-pack of pipes, it becomes significantly more difficult practically to secure and seal tightly with construction plastic, so using construction foam seems like a better option.

 

[frökenfräken]

6 pipes (plastic pipes) LK systems sounds like underfloor heating?
If so, it won't be as hot. Underfloor heating in an old moderately insulated house maybe +30C(?) whereas wood, oil, or electric boilers from the '70s or older usually have radiators that are small and can circulate radiator water up to +80C (in full winter cold).

With a six-pack of pipes, it becomes significantly more difficult practically to secure and tape tightly with building plastic, so the alternative of building foam seems better.

The house is a single-story '70s house that originally used oil for heating. The house has since been expanded with an additional floor, extra insulation, windows replaced, and the heating system is now air-water. There is piping to radiators on the upper floor that runs through the basement via the closet, and water to the bathroom goes through the same closet. If this makes any difference.

 

[Oldboy]

Then it's probably warmer than +30C but not +80C.

You can dry swim a little and just feel with your fingers how it seems to try to pack tightly, and not least if it's possible at all to get a piece of building plastic that fits and can be taped tightly against all pipes. I would think that building foam is the reasonably functioning solution in practice. Then it might not be super critical in this case if the building foam is in good condition and stays sealed in +20 years?

 

[frökenfräken]

Then it's probably warmer than +30C but not +80C.

You can try dry swimming a bit and just feel with your fingers how it seems to try to pack hard, and not least if it is at all possible to be able to get a piece of building plastic that fits and that can be taped tightly against all pipes. I would think that construction foam is the reasonably functioning solution in practice. Then perhaps it is not super critical in this case if the construction foam is in good condition and stays tight in +20 years?

Thanks! Are fogskum and construction foam different things? Excuse a novice question.

 

[MathiasS]

Post a picture. And how wide is the gap around the protective tube that you need to seal?

 

[Oldboy]

Thank you! Are "fogskum" and "byggskum" different things? Excuse a novice question.

As far as I know, they are the same thing. It depends on what you use it for. Normally, you would use "fogmassa" for joints. "Fogmassa" and "byggskum" are not the same thing. They work in different ways and therefore have different areas of use.