S-Trap

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#1

Originally Posted By: Steven Brewster
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Hey guys,


Would you consider this set up an S-type trap?? All of the sink drains are installed as shown and are not vented at the fixture. There is only one 3 in. vent for the entire home! Most sinks gurgle when emptied.


[ Image: http://www.nachi.org/bbsystem/usrimages/P/P1030288.JPG ]

#2

Originally Posted By: Jay Moge
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i don’t think that is an “s” trap. it looks like a home store bought trap for a floor mounted drain. that about the only way to incorparate a trap. an “s” trap would be if there was a bend going down, up, down and then horisontal. i’d be curios to know if there is another trap under the floor that the home owner was unaware of when he installed this one. there usualy is one between the floor joists that you can’t see. icon_cool.gif


double traps will also cause the gurgle noise. a 3'' vent for 1 kit. sink, 1 bathroom should be enough, unless for some odd reason all drains are used to full copasity at the same time (not likely)

#3

Originally Posted By: Steven Brewster
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I realize that this is not a true S-type trap but I would think it would work on the same principle. If I’m correct ?, S-type traps can siphone on its on or when another fixture (unvented or not) drains and can break the water seal causing sewer gases to enter the residence. Just didn’t know if this set up would act in the same manner.


There were no traps for the fixtures in the crawlspace, except for the tubes. This home has 2 full baths and washing machine located > 40' from a vent.

#4

Originally Posted By: wcottrell
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My friend that is an s trap


Regards Bill

#5

Originally Posted By: rmoore
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I’m with Bill. Looks like a classic S-trap to me.


Could be repaired by installing an AAV (Air=admittnace valve).

--
Richard Moore
Rest Assured Inspection Services
Seattle, WA
www.rainspect.com

#6

Originally Posted By: phinsperger
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It is an S-trap.


The shape of the sink will also partly determine if there is going to be a siphoning problem.

--
.


Paul Hinsperger
Hinsperger Inspection Services
Chairman - NACHI Awards Committee
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here !

#7

Originally Posted By: lewens
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Why would you put a sink trap under the floor between the joists that you couldn’t see?

–
Just my usual 12.5 cents


From The Great White North Eh?
NACHI-CAN
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#8

Originally Posted By: rcooke
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lewens wrote:
Why would you put a sink trap under the floor between the joists that you couldn't see?

Pedestal sink no room for trap under sink see it all the time when they try to make the bath room look elegant

--
Roy Cooke Sr.

http://Royshomeinspection.com
#9

Originally Posted By: lewens
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Tuck it in behind the pedistal roy.


Larry

–
Just my usual 12.5 cents


From The Great White North Eh?
NACHI-CAN
www.aciss-brant.com
www.certifiedadulttrainingservices.com/

#10

Originally Posted By: rcooke
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lewens wrote:
Tuck it in behind the pedistal roy.
Larry


Not my job I just report what I find.

--
Roy Cooke Sr.

http://Royshomeinspection.com
#11

Originally Posted By: rwand1
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Probably an older house that had original S-trap. Likely redone this way because they could not put in a P-trap.

–
Raymond Wand


Alton, ON


The value of experience is not in seeing much,


but in seeing wisely. - Sir William Osler 1905


NACHI Member


Registered Home Inspector (OAHI)


http://www.raymondwand.ca

#12

Originally Posted By: jpope
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rmoore wrote:
Could be repaired by installing an AAV (Air=admittnace valve).


Without a trap arm, an AAV will do nothing to correct this set up.

The absence of a trap arm is how an "S" trap is defined (regardless of its orientation).

In most cases, the trap arm (the horizontal pipe from the weir to the vent) is required to be a minimum of 8 inches in length.

--
Jeff Pope
JPI Home Inspection Service
"At JPI, we'll help you look better"
(661) 212-0738
#13

Originally Posted By: rmoore
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Quote:
Without a trap arm, an AAV will do nothing to correct this set up.


Jeff, I have to disagree. Island sinks are now often vented this way for the very same reason that there is no wall drain. I have a couple I installed in my own kitchen that look very similar to the diagram below. Somewhere I have better diagrams of allowed set-ups but I can't seem to find them right now.

![](upload://ubWXJD90KgQBX6ZH1dCGQY15EaO.jpeg)

Anyway, I see no reason Steven's sink could not be adapted the same way to prevent siphoning.

--
Richard Moore
Rest Assured Inspection Services
Seattle, WA
www.rainspect.com
#14

Originally Posted By: rmoore
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a better image…


![](upload://2WUNmjb87KSwwEx6F7sTfGc4NMk.jpeg)

--
Richard Moore
Rest Assured Inspection Services
Seattle, WA
www.rainspect.com

#15

Originally Posted By: jpope
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(from your image)


![](upload://xy2d12b6H311XlG0sXJ4yxUqCu5.jpeg)

as pictured here.

The length of that horizontal run can be no less than 2X the diameter of the trap weir for a "crown vent" (standard drain/vent system as in your image), and no less than 8 inches for a "vertical leg," which would be necessary based on the original picture.

--
Jeff Pope
JPI Home Inspection Service
"At JPI, we'll help you look better"
(661) 212-0738

#16

Originally Posted By: rwand1
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I have seen these Air Admittance Valves placed on the horizontal section of the waste line. Most always installed in modified plumbing systems in older housing.


Most times I will flush the toilet or run shower/bathtub to try and hear if there is any gurgling fom the sink or bathtub. It is not uncommon to hear this in older homes with S-traps.

The auto-vent seems to be a good work-around, but I can't say as to how you would test it and ensure it works? Let alone the manner it which it is installed in some cases. Just because you don't hear any gurgle is not a guarantee of no problem.

--
Raymond Wand
Alton, ON
The value of experience is not in seeing much,
but in seeing wisely. - Sir William Osler 1905
NACHI Member
Registered Home Inspector (OAHI)
http://www.raymondwand.ca

#17

Originally Posted By: rmoore
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Hi Jeff…


I don't mean to be a pain, but as we would be effectively changing the original set-up to my diagram wouldn't the 2x apply? (BTW...where is that 8" stated...I can't find it). Granted it's tighter than under a kitchen sink, but either 3" or 8" I still think it could be incorporated with an AAV and some creative (but allowable) plumbing. The AAV can also be Teed off the trap arm.

I suspect many plumbers would now fix Steven's problem with a properly installed AAV (assuming local codes allow it) rather than tear the walls down trying to install a normal wall outlet and through roof vent.

Just took a photo of one of mine...my trap arms are definately long enough. ![icon_biggrin.gif](upload://iKNGSw3qcRIEmXySa8gItY6Gczg.gif)

[ Image: http://www.nachi.org/bbsystem/usrimages/0/051017N035.jpg ]

--
Richard Moore
Rest Assured Inspection Services
Seattle, WA
www.rainspect.com

#18

Originally Posted By: lkage
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rmoore wrote:


Just took a photo of one of mine...my trap arms are definately long enough. ![icon_biggrin.gif](upload://iKNGSw3qcRIEmXySa8gItY6Gczg.gif)

[ Image: http://www.nachi.org/bbsystem/usrimages/0/051017N035.jpg ]


Looks good, Richard and I believe that is an easy fix for many "S" traps.

--
"I have never met a man so ignorant that I couldn't learn something from him."
Galileo Galilei
#19

Originally Posted By: jpope
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rmoore wrote:
I don't mean to be a pain. . .


I don't consider intelligent conversation to be "painful." ![icon_wink.gif](upload://ssT9V5t45yjlgXqiFRXL04eXtqw.gif)

rmoore wrote:
but as we would be effectively changing the original set-up to my diagram wouldn't the 2x apply?


The problem in the original post (as I see it) is the location of the actual drain which appears to be in a direct line vertically beneath the sink drain (not enough off-set for a proper trap and vent), hence the orientation of the "S" trap.

rmoore wrote:
(BTW...where is that 8" stated...I can't find it).


IRC P3105.3(3) Vertical leg for waste fixture drains.

rmoore wrote:
Just took a photo of one of mine...my trap arms are definitely long enough.


I agree. Yours is a standard "crown vent" where the 2X rule applies.

--
Jeff Pope
JPI Home Inspection Service
"At JPI, we'll help you look better"
(661) 212-0738
#20

Originally Posted By: Steven Brewster
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Hey Guys,


Thanks for the input. I had reported it as S-traps and recommended repair by a lic. plumber. This home is 5 years old, in the country, with many deficiencies. I can't believe what some people get away with when a city inspection is not required/available. Who suffers, the un-informed owner!!!!

Again,
Thanks!!

Steven