Bathroom waste, too many bends on WC?

[Coll659]

Hi all. Just put in the waste for my bathroom which will go below Dpm, insulation and concrete, before I fill in the trenches and put my insulation on top i wanted to check if what I've done is all good. 

 

Bath waste in 50mm (for free standing bath) in corner with 50mm vent coming off and going up the wall and outside. Joins midway with the shower waste from the other corner (also in 50mm) and then continues in 70mm to the third corner where the toilet joins it and it goes to 110mm. It then does a 45 turn to go through the wall where the plan will be to do a 90 turn and go through the wall to the soil stack (it joins with the 50mm waste from the kitchen and utility just before going through the wall) 

 

I have kept a 1:40 fall in all the pipes 

 

I'm hoping it's not too many bends for the toilet? 

 

Any fundamental mistakes I have made? And feedback would be greatly appreciated

[Nickfromwales]

I'd give you a job  

 

Looks good afaic, just I prefer to solvent weld everything; as much as I can that is as the 110mm stuff I always use push fit for a bit of 'give'.

 

I think I'd bed the joints and changes of direction with some 8:1 sand and cement haunching, and let that cure before going over, unless you were going to back-fill with concrete anyways?

[Nickfromwales]

No real need for the 50mm vent btw, as you only need air admittance / air break if the invert (drop) is >1300mm. The fact that the pipework is largely horizontal provides the air break. I assume this is a ground floor so no need for air admittance imo.

[Coll659]

Thanks nick I was hoping to get your feedback. Great to know it's looking good. I wasn't sure about the vent but wanted to be safe rather than sorry. I guess there's no harm leading it since I have it dug out already? And yeah I will bed it with sand and cement as you suggest then fill around the edges and top with what I dug out before putting the insulation down

 

Thanks again

[ETC]

How do you rod the pipework?

[Nickfromwales]

The fitting outside can simply be an 'access' fitting with a screw cap on it.

[Nickfromwales]

[saveasteading]

11 hours ago, Nickfromwales said:

some 8:1 sand and cement haunching

Good move. It will hold it all in place, fill any tiny gaps, stand up to careless feet, but still allow it to joggle if the building moves.

[Temp]

Tip with solvent weld is to use enough solvent. If you are mean with it then it grabs too quickly. If reasonably generous you have time to rotate the pipe to the angle you want.

[Coll659]

Thanks for the tips, much appreciated