Installing drain/soil pipe through an existing foundation

[D2bee]

Hi All, 

I have been reading some stuff on here and appreciate the generosity of you all in this community. 

This is my first self build/major extension project and will appreciate all the help available from all you Knowledgeable and experienced people are out there. 

I bought a property which the previous owner had commenced a double storey extension project with foundations in situ. However there is need for a ground floor toilet for which drainage provision was not made before the foundation was completed.  

My question is this:

How can the drainage/soil pipe be inserted through the foundation to the manhole (located next to the foundation) without compromising the integrity/strength of the foundation? 

Any ideas will be most appreciated. 

 

 

  

[tonyshouse]

Diamond drill the hole, 150mm for 110mm drain surround with foam or polystyrene 

[Conor]

1. run it above the concrete slab - if you have the floor build up available for a 110mm pipe plus fall. Looks like a standard floor of 100mm imsulation. and 100mm screed? Should work. Then use concrete lintels or steel duct when you go through the cavity wall.

 

If you need a greater fall or depth:

 

2 get a floor saw and cut a slot out of the slab from the toilet to the edge, and then dig to the required depth. Bed the pipe, reinstate etc.You'll need to double check with the structural engineer - esp of there is rebar or mesh in the slab.

 

 

Edited October 22, 2021 by Conor

[tonyshouse]

I would dig a hole both sides and smash out blocks and bricks to concrete level, lay pipe, build in lintels and blocks/blocks on top to match. 

[D2bee]

 

 

21 minutes ago, tonyshouse said:

I would dig a hole both sides and smash out blocks and bricks to concrete level, lay pipe, build in lintels and blocks/blocks on top to match. 

 

24 minutes ago, tonyshouse said:

Diamond drill the hole, 150mm for 110mm drain surround with foam or polystyrene 

Sorry just trying to get used to the forum.  Thank you both. Both ideas seem good and workable the line of the channel in the manhole is about 20-30cm below the slab and given the length, cutting through the foundation seem to be the only option to get the fall. The length is just over 6m.

Edited October 22, 2021 by D2bee

[D2bee]

20 minutes ago, Conor said:

1. run it above the concrete slab - if you have the floor build up available for a 110mm pipe plus fall. Looks like a standard floor of 100mm imsulation. and 100mm screed? Should work. Then use concrete lintels or steel duct when you go through the cavity wall.

 

If you need a greater fall or depth:

 

2 get a floor saw and cut a slot out of the slab from the toilet to the edge, and then dig to the required depth. Bed the pipe, reinstate etc.You'll need to double check with the structural engineer - esp of there is rebar or mesh in the slab.

 

 

Thanks for these. Yes it is a 100mm screed and 100mm insulation.

Just worried if is enough room for the fall given its just over 6m length to the outer skin  

[Dave Jones]

13mm per M is min fall so plenty of scope.

[D2bee]

On 22/10/2021 at 18:43, Dave Jones said:

13mm per M is min fall so plenty of scope.

Thanks,

Much appreciated.