Question about a drain smell

[JCplumb]

Hi guys,
My mum's had a plumbing issue in her house that has gone on for a year or two.
Every so often, maybe every 2 weeks or so, when she empties the bowl in the kitchen, or runs the tap in the kitchen she can smell the drains in her living room.
There's a solid floor in the kitchen and the kitchen waste goes outside into an external drain.
I'm wondering if anyone has come across anything similar, I don't have the tools to do a drain survey and she seems to be happy putting up with it - when it happens she puts a load of caustic down the drain which clears it for a couple of weeks.
I'm sure the drain must go under the house and has a fault somewhere either under the kitchen or living room, problem is she's not very mobile and because she doesn't want the disruption she hasn't let me take any of the floor up in the living room to check.
I'm not a drains man by any means, any jobs I've come across where digging up drains is involved I've passed on to someone else in the past, so just wondering if any experienced guys may have any ideas or know of any ways to diagnose without a survey.
Thanks.

 

[wiggers]

Bit drastic digging up drains! Does your mum have her washing machine waste connected via the sink waste as this is one of the main problems with smells. If so put a new mcapine WM2 trap on or better still have its own separate waste, but if not there could still be a problem with the trap as gunk has breached the water line seal.

 

[JCplumb]

The waste under the sink and the washing machine connection are sound.
The smell isn't from the sink directly, when the sink is used the smell appears in the living room. Definitely a drain problem.
Just thought, I'll tip a bowl of water down the outside drain to make 100% sure.

 

[Paulus]

That'sweird, I have just come across a similar problem today. Went to a house to quote for a new bathroom, ran hot and cold water in the bathroom to check pressure and when I went downstairs to the kitchen there was a smell which I can only describe a sulphurous.

The customer says it always happens when the hot water is run in the bathroom. As in your case JC the smell isn't coming from the sink waste but the waste pipe does go under the concrete floor.

I would be interested in any ideas.

 

[lbp plg & htg]

This is exactly same at my mothers? Lives in a bungalow, solid floor?? Cleaned the trap out again last week whilst fitted NEW WASHER again so time will tell??