Adding access to underground drain

[mrsplodge]

I have a 1970s house which has started developing some cracking, so the first thing we did was organise a drain survey to make sure the drains are OK. The problem is, the survey was unable to access the section of the main drain under the house where the cracking is. The soil pipe runs up through the house and out of the roof, and goes down underneath the floor and out under the front wall of the house. There's a rodding point in the front garden, but it is angled downstream from the section of the drain, so there's no way to get a camera back upstream under the house. This drain connects to another further downstream at an angle too, before it gets to the manhole in the street, so can't get a camera from the manhole back up. We tried drilling an access hole in the soil pipe in the loft and dropping the camera down, but only managed to get down to the ground floor level and not underneath the house, due to the bends in the pipework as it travels down to through the house.

I think I need to create some kind of access near the rodding point to be able to camera upstream. So I think my options are either to cut into the drain outside and install an inspection chamber, or I'm wondering if it's possible to dig down to the pipe outside and install one of these access saddles on the top: https://www.mpmoran.co.uk/soil-vent-access-saddle-pvcu-black-110mm-100005425. I could then put some risers in and a cover. I'm wondering if those access saddles are OK to install horizontally onto the top of the drain pipe. It seems like that would be much easier than having to cut out a section of the pipe to install a full inspection chamber.

 

[Scally-Ho]

Before I can answer you, I need to know what material your existing drain is made from. Different materials require different approaches.
If its salt glaze, then a drilling to remove a top section will facilitate the cementing on of a SG saddle.

 

[mrsplodge]

It's PVC pipe

 

[Scally-Ho]

It's PVC pipe

That is an easy job then by using slip couplings and a branch assisted by a good lubricant.

 

[mrsplodge]

OK, so just a 90 degree branch (not 92.5 degree to make it easier to go upstream), and a screw cap or something on the branch? Can you get branches which accept slip couplings on both ends? I can only find ones which have either a socket and spigot, or two sockets. It would be easier with a spigot on both ends, then I could cut a section of the pipe the same size as the branch and just put slip couplings on both sides, without having to use a small section of pipe on the socket end of the branch.

 

[Hugh Jaleak]

If you've got plastic drain then grafting new sections in is easy enough. I'd dig down, find the point where the existing junction is for the rodding point, remove that and install a 450mm Chamber instead. Gives you access both ways and futureproofs the place should you ever get further issues.

Although, if all the drainage is plastic, I'd be surprised if its broken, unless there's been major movement.

 

[camerart]

Hi,
If you can block the pipe at the rodding point with a bung, te top the pipe up with water, it should stay at the same level, o look for damp spots.
C.