Waste pipes

[JackofAll]

Hi all,

All the waste pipes at back of house come out at same level from slab. Engineer specced 1/60fall back to septic. Should I put AJ's at every outlet pipe and then run onto a single pipe(with a couple of AJ's)heading to septic or run all outlet pipes to a single pipe with AJ's ( at each junction)then on to septic? See crude drawing.

[saveasteading]

You mean access Chambers? NB they lose height, about 60mm.

You have two fixed references, the bath outlet at the top of the run, and the tank if it is already in.

 

1. Tank not in?  Slope your drain from the top at 1:60, installing access Chambers according to the regulations.

All side entries are installed to fit, all being steeper than 1:60. It may need some bends.

Tank installed to suit the end level.

2. Tank already in? Either lay as above and adjust the final length to suit, or average out the fall.

 

Check the levels before starting.

 

Do you mean septic? That would imply it is an existing, rather old, tank.

[JackofAll]

9 hours ago, saveasteading said:

You mean access Chambers? NB they lose height, about 60mm.

You have two fixed references, the bath outlet at the top of the run, and the tank if it is already in.

 

1. Tank not in?  Slope your drain from the top at 1:60, installing access Chambers according to the regulations.

All side entries are installed to fit, all being steeper than 1:60. It may need some bends.

Tank installed to suit the end level.

2. Tank already in? Either lay as above and adjust the final length to suit, or average out the fall.

 

Check the levels before starting.

 

Do you mean septic? That would imply it is an existing, rather old, tank.

Access junction/Access chamber, we just call em AJ's round this neck of the woods. Percolation test(new build) deemed a septic with Percolation area as suitable for the ground conditions. Haven't installed it yet, my thinking was to get the pipes in first and connect last to the septic. So option 1 it is then, thanks @saveasteading.

[saveasteading]

Who is doing the drain? Don't assume groundworkers control the slope properly. They often just guess, at your expense.

Diy? Use a long spirit level and tape packing under one end. 1:60 requires 6mm of packing under a 1m level.

 

Can I persuade you to install a treatment package? You'll save a lot of money on the drainage field to justify the package extra. 

 

If your percolation is that good, I'd suggest rainwater goes into perforated pipes to dissipate it, instead of rubble soakaways 

[JackofAll]

8 hours ago, saveasteading said:

Who is doing the drain? Don't assume groundworkers control the slope properly. They often just guess, at your expense.

Diy? Use a long spirit level and tape packing under one end. 1:60 requires 6mm of packing under a 1m level.

 

Can I persuade you to install a treatment package? You'll save a lot of money on the drainage field to justify the package extra. 

 

If your percolation is that good, I'd suggest rainwater goes into perforated pipes to dissipate it, instead of rubble soakaways 

Diy, have taped a 30mm block to a 1800mm level. Treatment plants are way more expensive than the septic and less to go wrong with septic. The perc area is just 5/6 channels with 20mm stone at a depth of 450mm (I think) and already have the stone. Engineer has soakaway's on drawing but could ask him to change, save alot of hassle.