How to dig drainage trench next to concrete stumps?

BecB

Hi there,

We are looking to do some drainage down the sides of our house. 
We are looking to lay ag pipe at a depth of 300mm down the side of the house, with a stormwater drain at both ends to a depth of 300mm. 

My question is whether digging down 300-400mm right next to concrete house stumps will compromise the integrity of the stump? 
If it’s not okay, how would we lay drainage for this type of house to catch rainwater from the down pipe?

Photos are of existing drainage set up (or lack of).

Many thanks,

Bec 

JacobZ

Hi @BecB,

Thank you for your question about installing drainage next to the concrete stumps of your house.

Realistically, the downpipe should be plumbed into an underground stormwater pipe that runs to the council's stormwater system. Unfortunately, this is something you'll require the assistance of a plumber for. 

Installing some agi-pipe along the side of the house will help with groundwater, but if the main source of the water is the downpipe, then you should contact a plumber to have them connect the downpipe into the council stormwater system.

There is some potential for the stumps to shift if you were to dig right next to them, but typically concrete stumps will extend a good distance into the Earth so it's not necessarily a certainty. Digging won't affect the integrity of the stump itself, but removing the soil around it can allow the stump to shift. 

Due to the age of the house, it may not be possible, but if you have access to the building plans, the depth of the concrete stumps may be noted on them. If they extend well past 300mm, it should be fine to dig a trench, but some caution should still be taken.

My suggestion is to start by digging a 300mm hole next to one of the stumps along the side of the house and assess what you see. 

If you are not confident, it is probably best to contact a plumber for their assistance.

Let me know what you think and if you have further questions, please don't hesitate to reach out.

Jacob