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Open sewer port below basement floor with wood cover

  • Last Updated:
  • Apr 29th, 2019 11:08 pm
[OP]
Deal Addict
Jan 28, 2007
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SW Ontario

Open sewer port below basement floor with wood cover

Has anyone seen this strange set-up before?

House is approx 50 years old, and under the carpet (and underpad) that was on the basement floor we discovered a wood frame with a plywood access cover. It wasn't nailed down but a very tight fit and when we opened it, we could look straight down into the tile sewer line as it exits the house. We were checking the house for floor drains and was planning to install one-way traps in them to prevent possible radon entering into the house.
Measuring from the surface of the basement floor, the top of the open tile drain port is down almost 12" where you can also see the end of the foundation footing.

While I know this would be used as a cleanout, I am puzzled as to why it would have been left like this unless it was intended to possibly drain water from under the basement floor slab. I do know the house does have weeping tile around the outside perimeter, so I am not sure why they would need to leave it like this.

I am considering prying out the wood framing, scraping the sand around the tille away to install a Fernco MJ and running a piece of PVC up to floor level with a screw in access cap, then fill in around it with concrete mix.
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18 replies
Deal Addict
Nov 9, 2008
1290 posts
327 upvotes
Toronto
If that is directly into your drain (no ptrap) then you must be getting some seriously stinky sewer gas coming out of that. You should get a proper cap on that ASAP. What your described sounds good, be careful with the clay as it may be brittle - last thing you'd want to do is crack it!

Are you sure this is your drain line? Easiest way to confirm is flush a toilet and see if you see water. If not, likely old clay weeping tile system or storm drain line. Do you downspouts go onto your lawn or into a pipe in the ground (stormline/weepers)
[OP]
Deal Addict
Jan 28, 2007
2123 posts
1441 upvotes
SW Ontario
jacquesstrap wrote:
Apr 27th, 2019 5:53 pm
If that is directly into your drain (no ptrap) then you must be getting some seriously stinky sewer gas coming out of that. You should get a proper cap on that ASAP. What your described sounds good, be careful with the clay as it may be brittle - last thing you'd want to do is crack it!

Are you sure this is your drain line? Easiest way to confirm is flush a toilet and see if you see water. If not, likely old clay weeping tile system or storm drain line. Do you downspouts go onto your lawn or into a pipe in the ground (stormline/weepers)
No smell at all, and we've never had any odour issues in the 20 years we've been in the house.

At the moment I'm not rushing to fix it ASAP given it's been this way for 50 years, as I'd rather understand why and what impact any changes I make will do.
I'm also considering opening up the floor directly behind it and installing a backflow preventer all at the same time.
I work in a plumbing related industry and know for sure that it is my main line out of the house, as the photo shows water flowing from a tap I left running to check already.

Ya, clay can be a little brittle if your not careful and gentle, it would be worse if it was older ... it isn't the first time I've worked on clay pipes, if it breaks I'll just replace the section or line.
I'd rather be outdoors camping, kayaking, and mountain biking ...
Deal Addict
Nov 9, 2008
1290 posts
327 upvotes
Toronto
Since you're getting no smell and it's right before it exits the house, my bet is that you have a building trap. Do you know if you have one?

I'm being this was/is being used as a clean-out/access for the trap.
[OP]
Deal Addict
Jan 28, 2007
2123 posts
1441 upvotes
SW Ontario
jacquesstrap wrote:
Apr 27th, 2019 7:59 pm
Since you're getting no smell and it's right before it exits the house, my bet is that you have a building trap. Do you know if you have one?

I'm being this was/is being used as a clean-out/access for the trap.
Given that it's litterally 6" from where it exits the house, no there is not a whole house trap.
While I don't smell any sewer gases here, my Airthings Wave Plus spiked on the TVOC count this afternoon when I had it opened ... we also had a heavy day of rain a day or so ago, so I am sure that they extra water helped flush out the sewer lines as well in our area.
I'd rather be outdoors camping, kayaking, and mountain biking ...
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Aug 12, 2007
3472 posts
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Waterloo
Jojo_Madman wrote:
Apr 27th, 2019 10:05 pm
Given that it's litterally 6" from where it exits the house, no there is not a whole house trap.
While I don't smell any sewer gases here, my Airthings Wave Plus spiked on the TVOC count this afternoon when I had it opened ... we also had a heavy day of rain a day or so ago, so I am sure that they extra water helped flush out the sewer lines as well in our area.
Its not a sewer port. Sewers dont exist on residential lots, They are part of city infrastructure.

So it is, part of your :
1. drainage
2. weeping tile system
3. rainwater drainage system
----
Pay it forward.
[OP]
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Jan 28, 2007
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SW Ontario
Supahhh wrote:
Apr 28th, 2019 3:23 am
Its not a sewer port. Sewers dont exist on residential lots, They are part of city infrastructure.

So it is, part of your :
1. drainage
2. weeping tile system
3. rainwater drainage system
Yes, I only had used the term sewer line to clarify that it was indeed the houses main waste drainage line out to the sewer system. The main waste stack is ABS and has a typical clean out on the vertical section as it comes out of the floor. There is a floor drain in the same room as the drain stack that is tied into the main waste drainage line.
But there are no other floor drains or access points, other than this odd partly finished port as originally posted.

There is no interior weeping sub floor drainage system.

The outside perimeter weeping tile system is corrugated plastic pipe as years back I had to dig a post down close to the house and had exposed it.

There is no provision for eaves drains on this house.

From a residential design perspective, the way this pipe has been left is wrong for a number of reasons, but before I do something about it, I'm consulting here to see if others have encountered something similar.

As for sewers on residential lots, you are wrong, as they do exist in various cases around any city. While for the majority of homes they don't exist on residential lots unless the city has an easement and right of way on the property.
I'd rather be outdoors camping, kayaking, and mountain biking ...
Deal Addict
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Aug 12, 2007
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Waterloo
Jojo_Madman wrote:
Apr 28th, 2019 7:53 am
Yes, I only had used the term sewer line to clarify that it was indeed the houses main waste drainage line out to the sewer system. The main waste stack is ABS and has a typical clean out on the vertical section as it comes out of the floor. There is a floor drain in the same room as the drain stack that is tied into the main waste drainage line.
But there are no other floor drains or access points, other than this odd partly finished port as originally posted.

There is no interior weeping sub floor drainage system.

The outside perimeter weeping tile system is corrugated plastic pipe as years back I had to dig a post down close to the house and had exposed it.

There is no provision for eaves drains on this house.

From a residential design perspective, the way this pipe has been left is wrong for a number of reasons, but before I do something about it, I'm consulting here to see if others have encountered something similar.

As for sewers on residential lots, you are wrong, as they do exist in various cases around any city. While for the majority of homes they don't exist on residential lots unless the city has an easement and right of way on the property.
Fill the tub with about 10 gallons of water ( or fill a bucket with 10 gallons of water ) pout a dye in it , and flush it down the drain. Check to see if you see that color here.

This seems to be a Clay pipe. Is this House part of a development or is this a neighborhood with older homes where houses were knocked down and rebuilt?
----
Pay it forward.
[OP]
Deal Addict
Jan 28, 2007
2123 posts
1441 upvotes
SW Ontario
Supahhh wrote:
Apr 28th, 2019 9:17 am
Fill the tub with about 10 gallons of water ( or fill a bucket with 10 gallons of water ) pout a dye in it , and flush it down the drain. Check to see if you see that color here.

This seems to be a Clay pipe. Is this House part of a development or is this a neighborhood with older homes where houses were knocked down and rebuilt?
Uhm, I've already stated that I ran a tap to confirm this was the drainage line in the house, as well as several other related details.

Given that I stated the house was 50 years old, clay drainage pipes were commonly used in this era for residential waste drainage plumbing.

What I was looking for was if anyone had encountered something like this before, because as a graduate of Architect and 25+ years in the plumbling & mechanical engineering industries, I have never seen a drain line left like this before.
My suspicion is that it was meant to be finished off or changed when the house was built, but wasn't and has sat this way ever since.
I'd rather be outdoors camping, kayaking, and mountain biking ...
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Jan 2, 2012
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KINGSTON,ON
Jojo_Madman wrote:
Apr 28th, 2019 10:47 am
Uhm, I've already stated that I ran a tap to confirm this was the drainage line in the house, as well as several other related details.

Given that I stated the house was 50 years old, clay drainage pipes were commonly used in this era for residential waste drainage plumbing.

What I was looking for was if anyone had encountered something like this before, because as a graduate of Architect and 25+ years in the plumbling & mechanical engineering industries, I have never seen a drain line left like this before.
My suspicion is that it was meant to be finished off or changed when the house was built, but wasn't and has sat this way ever since.
I've never seen anything identical to this either. I think you may be correct in the last assumption. Basement bathrooms weren't common 50 years ago, but it doesn't mean someone wouldn't have requested a rough in. (Although, I believe it should be a long radius tee if meant for that.)
Assuming that it is tied to the main sewer line, it's unbelievable that you have no sewer gas coming in. The only thing that I can think that would prevent that would be a trap outside your foundation wall. I know you mentioned that there is no main house trap, but this is the only logical explanation.
Deal Guru
Aug 2, 2010
14312 posts
4181 upvotes
Here 'n There
Jojo_Madman wrote:
Apr 27th, 2019 5:09 pm
Has anyone seen this strange set-up before?

House is approx 50 years old, and under the carpet (and underpad) that was on the basement floor we discovered a wood frame with a plywood access cover. It wasn't nailed down but a very tight fit and when we opened it, we could look straight down into the tile sewer line as it exits the house. We were checking the house for floor drains and was planning to install one-way traps in them to prevent possible radon entering into the house.
Measuring from the surface of the basement floor, the top of the open tile drain port is down almost 12" where you can also see the end of the foundation footing.

While I know this would be used as a cleanout, I am puzzled as to why it would have been left like this unless it was intended to possibly drain water from under the basement floor slab. I do know the house does have weeping tile around the outside perimeter, so I am not sure why they would need to leave it like this.

I am considering prying out the wood framing, scraping the sand around the tille away to install a Fernco MJ and running a piece of PVC up to floor level with a screw in access cap, then fill in around it with concrete mix.
Radon does not come from open sewers but from the earth and natural stone and sometimes from well water. If it was radon then you likely wouldn't be posting a message on here as you'd be dead by now! You might want to get a radon test if you are concerned (avail at hardware stores).

What you need to be concerned about is sewer gas but if there is a trap (ie U-shaped pipe) somewhere along your line then that's not a worry either. As for the one-way trap you are thinking of installing it seems you are referring to a backwater valve as that's the only thing that stops water from going 2 ways. It is not used to stop sewer gas from entering your home as that's what a trap is for. It stops your basement from flooding when the water goes backwards from the sewer line.
Deal Addict
Nov 9, 2008
1290 posts
327 upvotes
Toronto
Jojo_Madman wrote:
Apr 27th, 2019 10:05 pm
Given that it's litterally 6" from where it exits the house, no there is not a whole house trap.
While I don't smell any sewer gases here, my Airthings Wave Plus spiked on the TVOC count this afternoon when I had it opened ... we also had a heavy day of rain a day or so ago, so I am sure that they extra water helped flush out the sewer lines as well in our area.
Building traps can be located on the exterior of your home (Source: a friend just had theirs removed and it was outside their foundation/footings). Are you sure you don't have one - have you scoped the line to confirm?

The fact you're not getting any sewer gas smell from that open main drain line makes me suspect you do. I have a clean-out in the floor that goes directly into the main sanitary drain line and when I open it up you can really smell the sewer gas.
[OP]
Deal Addict
Jan 28, 2007
2123 posts
1441 upvotes
SW Ontario
MrFrugal1 wrote:
Apr 28th, 2019 11:06 am
I've never seen anything identical to this either. I think you may be correct in the last assumption. Basement bathrooms weren't common 50 years ago, but it doesn't mean someone wouldn't have requested a rough in. (Although, I believe it should be a long radius tee if meant for that.)
Assuming that it is tied to the main sewer line, it's unbelievable that you have no sewer gas coming in. The only thing that I can think that would prevent that would be a trap outside your foundation wall. I know you mentioned that there is no main house trap, but this is the only logical explanation.
The capet underpad was quite dense and taped down very well over the wood cover and along the wood board seams. The plywood lid was a very tight snug fit and I had to use the end of a chisel and thin pry bar to get it off, which probably helped with preventing odours. As well, I did have the basement window open when I was working and the wind was pressurizing the house, as I could feel the air drafting downwards into the hole.

I know there had to be some sewer gases coming in as my Wave Plus spiked on the TVOC during this time ... I wasn't exactly sticking my face in the hole and breathing heavy either given what I know about what methane can do to you if you get a big dose.
I'd rather be outdoors camping, kayaking, and mountain biking ...
[OP]
Deal Addict
Jan 28, 2007
2123 posts
1441 upvotes
SW Ontario
eonibm wrote:
Apr 28th, 2019 11:17 am
Radon does not come from open sewers but from the earth and natural stone and sometimes from well water. If it was radon then you likely wouldn't be posting a message on here as you'd be dead by now! You might want to get a radon test if you are concerned (avail at hardware stores).

What you need to be concerned about is sewer gas but if there is a trap (ie U-shaped pipe) somewhere along your line then that's not a worry either. As for the one-way trap you are thinking of installing it seems you are referring to a backwater valve as that's the only thing that stops water from going 2 ways. It is not used to stop sewer gas from entering your home as that's what a trap is for. It stops your basement from flooding when the water goes backwards from the sewer line.
Radon, as in Radon gas definitely can come up thru any drain lines connected to sanitary sewers that aren't either capped or have a trap installed on them. It doesn't kill you instantly, but raises your risk of cancer over long term exposure, and levels are not neccessarily stable and fluctuate over time.

I have a Radon monitor already running, which also monitors other things including VOC levels.

As for the backflow valve, I am very well aware what they used for and why. What I was considering was that if I have to open the slab up at all, I might as well consider installing one at the same time to prevent a flooded basement. However given the 20 years we have been here it's never been an issue to us or any of our neighbours, so its probabaly a null point especially being we are on the upper part of a large hillside.
I'd rather be outdoors camping, kayaking, and mountain biking ...
[OP]
Deal Addict
Jan 28, 2007
2123 posts
1441 upvotes
SW Ontario
jacquesstrap wrote:
Apr 28th, 2019 1:42 pm
Building traps can be located on the exterior of your home (Source: a friend just had theirs removed and it was outside their foundation/footings). Are you sure you don't have one - have you scoped the line to confirm?

The fact you're not getting any sewer gas smell from that open main drain line makes me suspect you do. I have a clean-out in the floor that goes directly into the main sanitary drain line and when I open it up you can really smell the sewer gas.
Interesting, did they have an access cover above it or was it buried in the yard and took some digging to locate it?

Depending on age and location, anything is possible if it is an older home ... the older they are, the crazier some of the things you see.
This place was built in 1971 so I am surprised that we discovered this, as it would be something more typical of the 1940's and 1950's ... at least its clay tile and not Orangeburg drainage pipes!

I have access to a scope and may do that out of curiosity.
I'd rather be outdoors camping, kayaking, and mountain biking ...

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