Smelly Odour Randomly Started

[PlumbingNoob]

I have had a mystery smell start in my house all of a sudden.
The smell is prominent in an adjoining linen closet to my bathroom and appears to e coming from subfloor.
My home sits on brick piers (single story) with a dirt subfloor and forced fan subfloor ventilation installed to keep it all dry.
Note: No recent plumbing works done in the house (>12 months since anything was touched)

I have had 2 plumbers out so far and both have stated the following and thus far not found root cause of the smell...

No blockages in the main sewer line (plumber check it with camera)
Plumbers say it smelt similar to sewage
No identifiable leaks in subfloor
Subfloor (dirt) is not wet in any area
All drains in the every room in the house do not smell (waste, shower, bath, toilet, laundry e.t.c)
No obvious dead rodent or animals in subfloor

Plumbers were unable to check the plumbing directly under the bathroom as their is no access to get a camera or jet in there without dismantling some of the plumbing (70's home).

The smell is very prominent in my linen closet and in the bathroom when my subfloor vents turn off for the night, and then when the vents are startup again in the morning, hence clearing the air under the house, removes all of that smell from the bathroom and 90% of it from the linen closet.

If all my p-traps are doing their job and I have no obvious source of the odour, what could be causing this mystery smell?

Both Plumbers recommended redoing all the under bathroom pipe work as they cannot be certain that there is no leak or crack in the pipes buried in the dirt before it joins up to the main sewer line.

Is this the right approach? If the smell does not dispersal or the pipe rework is not the fix, what do I do next? Running out of ideas.

Any advise welcome
Thanks
PlumbingNoob

 

[oz-plumber]

I wouldn't go as far as replacing the plumbing under the bathroom.
The waste and sewer pipes are dry most of the time, they never hold water.
If there is no sign of a blockage like pooling water or slow draining or bubbly sounds, then I doubt there is a blockage.

The smell might be from a leaking shower.
It could be rotting the timber and the smell only detected when the ventilation is turned off.

A little more investigation is needed before replacing all the plumbing.

 

[WC1]

Be very cautious of guys encouraging major works on the off chance it might fix the problem.
Where is the linen closet wall in relation to the shower/bathroom- there appears to be a correlation as you have noticed. ?
Damp in that wall as oz mentions could be the source.
A damaged plastic waste pipe- e.g. rodent damage can allow sewer gas out but may not cause a visible leak.
Also how are the waste pipes vented?

 

[Chuck]

No obvious dead rodent or animals in subfloor

Since there are no obvious wet patches or leaks either on the balance of probability I'd still suspect a dead mouse somewhere where it is not easily visible.

To me, a dead mouse smells similar to a domestic refuse bin that hasn't been emptied for a couple of weeks during warm weather.

 

[PlumbingNoob]

Be very cautious of guys encouraging major works on the off chance it might fix the problem.
Where is the linen closet wall in relation to the shower/bathroom- there appears to be a correlation as you have noticed. ?
Damp in that wall as oz mentions could be the source.
A damaged plastic waste pipe- e.g. rodent damage can allow sewer gas out but may not cause a visible leak.
Also how are the waste pipes vented?

On the other side of the linen closet in the bathroom is the toilet, then next to that is the basin and then next to that is the shower/bath.
The waste pipes are vented through a sewer vent located outside my 2nd bathroom at the rear of the house ( No issues in this bathroom) . The main bathroom (smelly one) is more toward the center of the house.
I have also cut holes in the back and sides of the linen closet (I can repair later) to inspect for dampness or leaks, and the result is all dry. There is no visible signs of water damage in the linen closet.
I do smell the same odour coming out of the fixed brick vent at the side of the house which is directly inline with the bathroom.
I think I am close to knowing the problem location but not the root cause (yet)
[automerge]1587385206[/automerge]

Since there are no obvious wet patches or leaks either on the balance of probability I'd still suspect a dead mouse somewhere where it is not easily visible.

To me, a dead mouse smells similar to a domestic refuse bin that hasn't been emptied for a couple of weeks during warm weather.

I certainly have not ruled a dead rodent out and am thinking of getting a pest expert in to inspect. The smell to me is like old wet mouldy socks but the plumber said he thought it smelt like sewage. I can't say I go around smelling sewage alot, so I trust his nose.
[automerge]1587385889[/automerge]

I wouldn't go as far as replacing the plumbing under the bathroom.
The waste and sewer pipes are dry most of the time, they never hold water.
If there is no sign of a blockage like pooling water or slow draining or bubbly sounds, then I doubt there is a blockage.

The smell might be from a leaking shower.
It could be rotting the timber and the smell only detected when the ventilation is turned off.

A little more investigation is needed before replacing all the plumbing.

Thanks Oz, I did go with the plumbing rework as it is something I feel needs to be done to future proof my home and also allow for regular cleanouts and easier maintenence for years to come (well my gut is telling me it is a good option) . I have another specialist in subfloor ventilation/odour/mould coming out next week as well to inspect (assuming the plumbing work does not fix the smell).
[automerge]1587385892[/automerge]

I wouldn't go as far as replacing the plumbing under the bathroom.
The waste and sewer pipes are dry most of the time, they never hold water.
If there is no sign of a blockage like pooling water or slow draining or bubbly sounds, then I doubt there is a blockage.

The smell might be from a leaking shower.
It could be rotting the timber and the smell only detected when the ventilation is turned off.

A little more investigation is needed before replacing all the plumbing.

Thanks Oz, I did go with the plumbing rework as it is something I feel needs to be done to future proof my home and also allow for regular cleanouts and easier maintenence for years to come (well my gut is telling me it is a good option) . I have another specialist in subfloor ventilation/odour/mould coming out next week as well to inspect (assuming the plumbing work does not fix the smell).

 

[Gasmk1]

Since there are no obvious wet patches or leaks either on the balance of probability I'd still suspect a dead mouse somewhere where it is not easily visible.

To me, a dead mouse smells similar to a domestic refuse bin that hasn't been emptied for a couple of weeks during warm weather.

This was what I was going to say some dead animal under the floor

 

[PlumbingNoob]

An update.
My plumber redid all my under bathroom pipe work and found when he dismantled the Gully, it gave of my foul smell.
He said that there was some clogged sewage in there and the rings around the gully may have been worn a bit and leaking the sewer gas.
Weird that there was no obvious blockage that both plumbers could find initially, but so glad the smell is GONE !

 

[oz-plumber]

On the other side of the linen closet in the bathroom is the toilet, then next to that is the basin and then next to that is the shower/bath.
The waste pipes are vented through a sewer vent located outside my 2nd bathroom at the rear of the house ( No issues in this bathroom) . The main bathroom (smelly one) is more toward the center of the house.
I have also cut holes in the back and sides of the linen closet (I can repair later) to inspect for dampness or leaks, and the result is all dry. There is no visible signs of water damage in the linen closet.
I do smell the same odour coming out of the fixed brick vent at the side of the house which is directly inline with the bathroom.
I think I am close to knowing the problem location but not the root cause (yet)
[automerge]1587385206[/automerge]

I certainly have not ruled a dead rodent out and am thinking of getting a pest expert in to inspect. The smell to me is like old wet mouldy socks but the plumber said he thought it smelt like sewage. I can't say I go around smelling sewage alot, so I trust his nose.
[automerge]1587385889[/automerge]

Thanks Oz, I did go with the plumbing rework as it is something I feel needs to be done to future proof my home and also allow for regular cleanouts and easier maintenence for years to come (well my gut is telling me it is a good option) . I have another specialist in subfloor ventilation/odour/mould coming out next week as well to inspect (assuming the plumbing work does not fix the smell).
[automerge]1587385892[/automerge]

Thanks Oz, I did go with the plumbing rework as it is something I feel needs to be done to future proof my home and also allow for regular cleanouts and easier maintenence for years to come (well my gut is telling me it is a good option) . I have another specialist in subfloor ventilation/odour/mould coming out next week as well to inspect (assuming the plumbing work does not fix the smell).

'Subfloor ventilation / odour / mould specialist'?

Please let us know the outcome....and the estimated costs for repairs

 

[PlumbingNoob]

'Subfloor ventilation / odour / mould specialist'?

Please let us know the outcome....and the estimated costs for repairs

I had my Subfloor ventilation / odour / mould specialist come out to my house.
He stated my existing subfloor ventilation is pretty good and does not need any changes. He did try and sell me some in roof ventilation which was aimed at keeping the inhouse room free from any condensation buildup over the winter months, which would prevent any potential mould buildups (which I do get minimal amounts of in the winter months).
He quoted me 5.6K (wow) for a new roof ventilation system and a new Solar Ark exhaust fan to help regulate the air in the roof space and inhouse living spaces. Cannot afford that after my recent plumbing works, so have postponed this until I feel it is absolutely necessary.
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Thankyou all for the advise you have given me during this post. This forum is awesome and will definitley use again !!!

 

[oz-plumber]

Thanks for the update

I would postpone the roof vents and ventilation system permanently.
5.6K - ??
Roof spaces are generally well ventilated, both sheetmetal and tiles.

Unless you can switch off the ventilation and close the vents in winter, I wouldn't bother.
You end up removing any heat in the ceiling space and replacing it with cold damp air.