Bathroom on the upper floor: ventilation shaft?

Hello,

a colleague who built last year pointed something out to me. Unfortunately, it’s very unclear and I don’t understand it yet, and then I could only ask if that was planned with us.

He says that something could occur with bathrooms on the upper floor, which would not be the case with bathrooms on the ground floor. In his case, they had to add a "shaft" in a late construction phase. The purpose of the shaft would be some kind of ventilation(?) and it is supposed to ensure that you don’t have unpleasant smells from the sewage system in the bathroom through the drain(?).

Unfortunately, I can’t explain it any better.

Help.

Regards

For every drainage, WC-WT-shower-bathtub sink etc., a collection pipe is inevitably required; experts call this a soil stack that must be vented through the roof. Without this ventilation, a WC flush will empty the water traps of the mentioned fixtures. Why? When a WC is flushed, a large amount of water suddenly flows into the drain pipe; for the water to flow freely down the soil stack, it needs air from above. The air is drawn in through the roof ventilation. If this ventilation is missing or too weak, the water amount from the WC flush will draw air from the drainage system where the least resistance exists, which is at the water traps of the bathtub and shower. These traps have the smallest siphon heights of 1-2 cm. If such a siphon, water trap, gets emptied by suction, the sewer ventilation happens at this point, and it smells.

In roof installations, which are often added afterwards, too little attention is often paid to the ventilation of the drainage pipes, and these unpleasant sewer odors occur. This can also happen if you go on vacation and these low water trap heights dry out. Pouring a shot of Glysantin or salad oil into the water traps helps prevent evaporation.

Best regards, Leo

Addendum: not Glysantin, the correct term is Glycerin. Salad oil becomes rancid over time, so it does not last as long as Glycerin.
leo

: Thank you very much for the great explanation. Now I understand it.

With this understanding, I was just able to ask my husband, and he says that such a pipe is already installed in our gable wall.
I hadn’t noticed that; all pipes were just pipes to me.
And for the pipe, a roof tile will be replaced with a special ventilated tile and connected.
Then hopefully we won't have any smelly showers.

Another point positively checked off, very nice.

Best regards

Hello everyone,

I'm jumping in here. We currently have an unpleasant problem with this ventilation pipe. We are living in an attic apartment at the moment, and our bedroom has only two skylights (which, by the way, I do not recommend! ). Some evenings we can't open the windows because it smells like sewage outside. There is an airflow from the ventilation pipe across the roof directly into our skylights... Is that normal, or should there be some kind of flap in the pipe? It's definitely very annoying because in the evening you can't just air out but always have to watch if it currently "stinks" outside.

Hello, if your roof ventilation is located near the roof windows, dormer, the vent pipe should be routed further up towards the roof ridge. Installing a flap as you intended is not permitted.

The same problem exists with chimney outlets, but there it is life-threatening if exhaust gases enter living spaces. So you have to see it this way with your roof ventilation for the wastewater stack: raising the roof ventilation higher is the only option. A sanitary installer is bound by the specifications of DIN 1986, which clearly states

If a ventilation pipe ends near living areas, it must be routed at least 1m above the window lintel or arranged so that it is at least 2m sideways from the window opening.” As demanded by numerous practitioners in recent years, this clear instruction from the old DIN 1986, Part 1 has been included in the new standard.

Just measure to see if the error lies in the system here.

Leo