Extending 110mm pipes through insulation and screed

[cwr]

Good evening,

 

The conundrum I am pondering today is how to extend a few 110mm pipes that come up through me floor. It's the one and only waste pipe bit i let the builder do (he insited he do the 110mm inside the footings...), and for reasons unknown he left some of the pipes sticking out of the slab by only 30mm. Next week the insulation goes in and then screed on top of the insulation. What i want is to have a push fit socket at finished floor level, about 225mm above the top of the slab. 

 

I thought it would be easy to extend the pipes, but a single push fit connector is too low, and two are too tall. Any bright ideas folks?

[ProDave]

Solvent weld slip coupling (that could be shortened if necessary) to join to a single socket coupling, again cut to length.  Not sure it would work but worth a try?