Outside trapped gully frothing over with soap

[Matt0029]

Is there likely a blockage in the outside trapped gully if it occasionally frothes up with soap. The external trapped gully at floor level just takes a 32mm pipe from a wash hand basin. Thanks.

 

[exedon2]

Simple answer yes crap job but needs cleaning out.

 

[Matt0029]

Just take they grill off and scoop out the bottom if it's a u bend? Maybe the bottle type do they have these external?

 

[Matt0029]

Thank you