Do foul water drains have to be buried?

[Gav74]

End terrace, pretty standard house. I have a downstairs toilet at the front of the house with a macerator and pipes running under the floorboards out to the foul water drain at the back.

I just spoke to a builder who says that as we're having decking all around the side and back of the building, he said we can just lay the pipe on the concrete path and have the decking over the top. Obviously then it'll have to be dug down into the main.

Is that ok or does the pipe have to be buried?

[Temp]

So he's proposing to move the macerator pipe from under the floor to outdoors on the surface?

 

Risk of freezing?

[ProDave]

I read it as removing the macerator (that was presumably put there because you could bot get enough fall on an underground pipe) and replacing it with a direct soil pipe, which to get enough fall would end up above ground, but covered by the deck.

[Mr Punter]

I think that ANYTHING is better than a macerator / Saniflo.  If you can get this to work with proper gravity drainage, do it.  You will not regret.  If the pipe is exposed to the sun you should use the black or grey stuff.  If it is underground or covered use brown, but ANYTHING is better than what you have (other than crapping in your own pants).

[Nickfromwales]

@Mr Punter

Much as I hate them too, let's be helpful  

@Gav74 can you clarify if the builder is saying cover the WASTE ( 32/ 40/ 50mm ) pipe or to convert to a FW ( 110mm soil pipe ) run? 

If it's still the macerator waste pipe then it can be insulated but not just left othewise exposed. 

The title says 'foul water', so we would assume 110mm. .