Roofing discussion!!!

[Frankenkubota]

at least one vent vertical through the roof. New home, 2 bathrooms. all vents connected, one vent. vent is for gas and to help water drain properly.

yes, when vented, the air pressure pushes the water down the drain, like gravity, it pushes but.......

If vented to the attic, the drain is exposed to the same air pressure so....it is vented, just not to the outside.

In my case i don't really care that much, i just want to understand.

 

[Frankenkubota]

There's no P trap on the main stack vent, so you're dumping methane into your attic. Also moisture. It's a very bad idea to vent directly into an ,attic.

There's no P trap on the main stack vent, so you're dumping methane into your attic. Also moisture. It's a very bad idea to vent directly into an attic.

i think that did it.

i'm guessing the p traps stop the gasses from re entering the specific room, ie bathroom or kitchen but once the waste is in the "main line", the gasses then escape thru the main vent?

now...... i did vent a washer drain into the attic and that was up to code. in portland oregon, 10 years ago. i guess gasses associated with the washer are not in the same league as bathroom gasses?

They have not got a whiff of my tee shirts after nailing up siding all day in this heat and humidity!

 

[pmsmechanic]

From Frankenkubota "i'm guessing the p traps stop the gasses from re entering the specific room, ie bathroom or kitchen but once the waste is in the "main line", the gasses then escape thru the main vent?"

Yes I would say that's the purpose of the "main line".

I agree on there being no P trap in the main stack.

The purpose of the vent is so that the P traps don't get their water siphoned out by the flowing waste water.

A toilet is it's own P trap.

What about a sink in an island? I've heard about a special kind of vent that can be installed right beside the sink in the island so that you don't need to connect to the main stack.

 

[Frankenkubota]

From Frankenkubota "i'm guessing the p traps stop the gasses from re entering the specific room, ie bathroom or kitchen but once the waste is in the "main line", the gasses then escape thru the main vent?"

Yes I would say that's the purpose of the "main line".

I agree on there being no P trap in the main stack.

The purpose of the vent is so that the P traps don't get their water siphoned out by the flowing waste water.

A toilet is it's own P trap.

What about a sink in an island? I've heard about a special kind of vent that can be installed right beside the sink in the island so that you don't need to connect to the main stack.

yea!

I love your forum name.

 

[Rockbadchild]

That's why I keep asking for explanations. Easy to condemn a method if you don't have to explain reasons and cost to do it the "right" way.

I have done many renovation and the jackpot I've seen is out of this world, 4 floor over each other, two, three set of shingles over each other just passing the cost and problem to the future. It can only work for so long, one day or the other it will have be done right which is to remove it all. If I redo a roof and the owner doesn't want to remove the old shingles I don't take the job. Why you are asking,..
Reason 1, the increase in weight (dead load) of the old shingles plus the new shingles on the roof and if you get more snow one year then your reginal historical average your roof could collapse.
Reason 2, (you don't get snow in your region fine) you cant tell if there is rotten board underneath, or it could be tongue and groove wood planks, which when dry it split when screwed in so your thin is actually not holding like it should and you could loose sheet in high wind or lets say you decide to shingles over existing shingles but there is already shingles underneath these shingles how thick are these shingles you might just be using 1 1/2 '' nails and these nails are not penetrating enough in the plywood underneath and 5 years after spending $7000 for a new roof a wind storm comes by and the whole thing rips apart then you would wish you would've don't it right and remove the old shingles.
reason 3, as mentioned above pushing the cost to the future one day or the other this old material will have to be remove maybe not by you but it will be by someone you cant indefinitely keep adding material. I have seen so many people thinking they wont be there to deal with it but ended up having to deal with it and where kicking themselves in nuts for making that mistake.

 

[EddieWalker]

My question is re the gasses. if you refer to the humidity i agree but again, the nasty gasses from the kitchen or bathroom are trapped by the.....P trap? No?

No, the P trap stops the gases from getting into the house, but the vent lines are clear all the way to the septic tank, or in town, all the way to the manhole.

A quick search of images found this picture. You can see how the trap is close to the sink, or whatever you are using. Then it flows into the main line. The main line is open from under the house, to above the house.

 

[MossRoad]

...

What about a sink in an island? I've heard about a special kind of vent that can be installed right beside the sink in the island so that you don't need to connect to the main stack.

That's called a studor valve, or air infiltrator valve. I have several in my very old house that at some point the original owner eliminated a main vent stack and moved it to the other side of the house. He never vented the kitchen sink, or the powder room sink. They'd gurgle when anything else was drained. I installed the Studor valves and that resolved that. Might want to check if acceptable to local codes.

 

[dieselscout80]

What is the best way to vent a oven through roof or wall?

I can do either and the wall is an upper section rather than the main end wall of the house.

 

[Rockbadchild]

What is the best way to vent a oven through roof or wall?

I can do either and the wall is an upper section rather than the main end wall of the house.

I don't know if you get any snow out in your area but if you do I would avoid using the roof to vent the oven it melts the snow and cause ice dam and it will eventually leak. use the least resistant path (Shortest distance with the lease amount of bends)

 

[Steppenwolfe]

That's called a studor valve, or air infiltrator valve. I have several in my very old house that at some point the original owner eliminated a main vent stack and moved it to the other side of the house. He never vented the kitchen sink, or the powder room sink. They'd gurgle when anything else was drained. I installed the Studor valves and that resolved that. Might want to check if acceptable to local codes.

We have used those as well for sinks under a countertop; a main vent line should exit the roof to vent as per Eddie's post.