condensation? in stench/open vent in loft

[Ghostrecon]

Hi we have an internal soil pipe and internal open vent - well it runs internally into the loft where it then exits through a ridge tile.

Its the one in the foreground here (the pipe in the background comes from an extractor fan in the main bathroom and exits through another ridge tile.

has always dripped a little water from the joins - it has not been solvent welded but just pushed together. Now I have upgraded the loft insulation it is leaking water constantly. I am assuming that this is condensation from moisture laden air inside the pipe. Should I just buy a load of solvent weld and sort out these joints ???? - I am quite confident to do do solvent welds up to 50mm pipe but these have 2 fixed ends so I dont want to bugger it up :-) I have tried taping up the joins but water is still weeping out both down the outside of the pipe and dripping from the bend. There is plenty of ventilation in the (blows a gale).

[Grimly Curmudgeon]

They're pushfit elbows and if they're leaking, just replace them - the rubber seals in them are shot.

[Ghostrecon]

I've pulled off the one on the left and there are no rubber seals or any grooves for them - I thought there would be because of the 2 ridges but they are smooth.

[Grimly Curmudgeon]

Strange design then. In that case, if they're a snug sliding fit you could glue them - soil pipe will glue ok, but get the position right first time, no second chances.