Foundations, sewers, and inspection chambers

[PeterTheCarpenter]

[Moderator comment: the following is copied from: https://forum.buildhub.org.uk/topic/43388-hello-there-i’m-new/#findComment-609872]

 

Thank you. Your reply hadn't been unnoticed. Thank you for the warming welcome. Thank you in deed.

 

Since then, I have been preparing quotes and gathering the facts. First fact, I have a listed property 150 years old. 2nd fact, I am an ex joiner trained in traditional joinery. So, i maybe rusty (16 years later). But, i know things.

 

Fact 3, I was quoted £3100 to move a brick inspection chamber and put to two pipes in the ground. With no warm fuzzy feeling, they are contacting the Council regarding listed building consent and confirming like for like materials. (Obviously I won't if I don't have too, plastic poo pipe seem far more sanitary to me than clay anyway)

So, groundworks. More precisely sewers. I have two inspections chambers within the boundary of my property. None of the two are on my searches conduct by the solicitor when retrieving information from Wessex Water on "march in". This tells me my two chambers are private. Yay for me, I am thinking, I can do the ground works myself.

 

Another fact, 2010 apparently, (from my homework spider sense) says water boards took on 1st sewers connecting to the main sewer line. This one is in the road, waaaaay from my boundary in my case and where the second chamber is. I am not moving this second chamber.

The second chamber appears to be having a legacy connection clogged up with dirt. So, to improve my design, I might reconnect this.

 

A CCTV inspection is also recommended before and after the inspection chamber move with listed building consent in mind.

 

I have done flush tests with the covers off tracked the flow and these two inspection chamber only serve my property which is indicative of a private sewer. 

I plan to build a veranda or extension with underfloor wet heating needing 100m type 1, 100mm concrete with rebar, 20mm softsand, DPC, 50mm screed, 50mm insulation, and 25mm tile and grout, roughly 345mm of flooring (above the 400m of pipe bedding encasing the pipe), oak beams, glass walls and glass roof with an area for solar. Additionally, I have plans to excavate a parking bay of EV charging and loft conversion  master suite later on. So ask permission for all??

 

Angles of 45 degrees and depths not exceeded in the next sewer in the series of chambers and pipe system needs to be rod-able and set between 200mm x 200mm of pipe bedding of pea gravel and 100 x 100 mm lintel of the pipework bridging foundations and I may need to used clay pipe instead of plastic.

 

Are foundations 450mm square these days??

Already from drawing this I see I need to re calculate the drop and the pipe bedding. I think it's possible with the space available, but only just.

Any thoughts on the whole process out there?? The permission to the technique? and methods used for best practice???

 

Thanks you.

 

[Iceverge]

On 11/04/2025 at 06:54, PeterTheCarpenter said:

plan to build a veranda or extension with underfloor wet heating needing 100m type 1, 100mm concrete with rebar, 20mm softsand, DPC, 50mm screed, 50mm insulation, and 25mm tile and grout, roughly 345mm of flooring (above the 400m

 

Unusual spec this. 

 

I'd prefer 

 

Type 1

Insulation 

DPM

Insulation 

Pipes staples to insulation 

100mm concrete powerfloated.