STP: Percolation test and herring bone field length

[BotusBuild]

(Thinking the answers to these 2 questions maybe linked ? )

1. Percolation test: is one necessary and can you provide a DIY result? FYI - We plan to get a warranty at the end of the build, "just in case".

2. How do you calculate how much soak away pipe in your herring bone field is required? Is there a useful website?

Thanks

[ProDave]

All the details of the test method and calculations are in building regs.  Hopefully someone will post a link. (I am only familliar with the Scottish version which are probably the same)

[Oxbow16]

What type of soil do you have?  

 

And have you any idea how high the water table is in winter and/or after heavy prolonged rain (aka summer)?

Edited August 27, 2020 by Oxbow16

[nod]

If you are on clay and sand like we were Three holes will just equal three ponds and a chunk of money wasted 

SE pointed this out to planners and they said ok no need 

[BotusBuild]

On 27/08/2020 at 13:13, Oxbow16 said:

What type of soil do you have?  

 

And have you any idea how high the water table is in winter and/or after heavy prolonged rain (aka summer)?

The ground is slate and soil mix called shillet (sp?) which does seem to drain well. We are onsite this week suffering the rainstorms, the surface seems to remain firm, and two pits about 1m deep are always "dry" (no pooling of water) after each heavy downpour.

The plot is near the top of a hill.

Overall I don't think I'm going to have a problem. So, do I need the percolation test (in particular to support a building warranty if i get one)?

[ProDave]

Yes, certainly in Scotland Building control will want to see the percolation tests and calculations.

 

It is possible to have ground that drains too quick, as well as too slow.