Missing drian pipes .... but lots of polystyrene !

[goalc]

Hi, I hope someone can offer some help !

We recently moved into a house where the kitchen adjoins the garage (the garage goes out further into the back past the outside wall of the kitchen) and the previous owner had moved the washing machine into the garage. The waste from the sink and dishwasher were redirected through the kitchen wall into the garage, where they put some drainage pipes in the garage under the floor to take the water into the main drains (somewhere - i dont know how they are connected but they do drain into the main drainage pipes).
We now want to disconnect all this, and put the sink and dishwasher waste drain back out through the back kitchen wall (you can see where they filled it in) and into the ouside drain........ however, we have dug up the area and cannot find any drain ! It looks like they removed the original drain pipe and presumably blocked the end off.

As we are digging up the area where we think the pipe should be and where we presume it was probaby disconnected, there are what looks like huge blocks of polystyrene.

Is this what is used to block the old pipes off ? Does this mean that we should find a sealed off joint in the pipe somewhere ? Any ideas why all this polystyrene (or whatever it is) is there ?

Any help or guidance is much appreciated...... thanks !

 

[noseall]

firstly have a look down any nearby inspection chambers to ascertain flow and depth, this also may tell you where the common line is (main run).
sometimes polystyrene is fitted as a friction buffer zone between foundations, but also, compressible material such as fibreglass insulation is wrapped around drain pipes, prior to concreting, if they happen to run through foundation trenches.
even with all this info in mind, even experienced builders can not always determine exactly where drain runs are. logic would suggest the shortest route between gulley and inspection pit, or main run.
trial and error and plenty of digging is sometimes the only answer.
it never ceases to amaze me what some people do underground!
just remember though, any drainage alterations is subject to b.c. approval and must be carried out under a buildings notice.

 

[goalc]

thanks for that.....so, if the change is subject to bulding control, would they have had to register this at the local council and if so will they have the plans so I can see what was done ?

 

[noseall]

its worth a pop. but don't be surprised if you get a negative response from building control. they may not have any drawings, particularly if the geezer doing the fist pipe alteration didn't do it under regs.

 

[goalc]

ok, i'll call them and see what happens....

taking the worst case scenario (no plans etc), any ideas what would be involved in trying to put a drain back and reconnect it ? Is this going to be expensive, in which case would I be best with sticking with how they have done it (we will only be in the house for 3 years max) ?

(The distance from where the drain used to come out of the back kitchen wall to where the new drain is in the garage is about 2 metres)
thanks...

 

[noseall]

like i said earlier, if you're prepared to dig a big hole and have plenty of room for the spoil, then it doesn't have to be expensive. a lot will depend on access. if the drains have been concreted over (usually only under driveways) and if there made of clay, then it might be a struggle without the proper tools.

 

[goalc]

Any ideas what would happen if I speak to the council and they say that there should have been building control approval to do what they did, but the previous owners didn't bother to do this ?

 

[noseall]

if its your intention to expose and alter the drains and susequently have them inspected, then i guess any work you do now will have to satisfy buiding control. no damage done.