Structural/Civils Design (Foundations, Drainage, Sewage Treatment Plant, SUDS)

[jimmyharris80]

Hi all,

 

We have our planning app in with the local authority at the moment, we are working with a timber frame co. to provide a design and build wind and watertight package.  They don't offer a groundworks/civils package so we are looking at establishing requirements, with a view to appointing a structural/civil engineer shortly.  We have a soil report already and the ground conditions are determined as firm silty clay, med shrinkibility.

 

Bit of detail on the site (see topo detail & proposed dwelling/garage attached)and what we'll need to incorporate into the design:

 

Foundations & B&B Ground Floor - TF co. will provide structural loadings once they've completed the design & BRs. post planning approval.  Site is pretty flat so I'd hope foundations should be fairly standard in nature (multiple fingers crossed!).

Storm Drainage - We are off grid, our existing bungalow discharges rainwater directly into a small stream that runs along the front of our land within our curtilidge or onto the driveway or surrounding garden, all very Heath Robinson!

Foul drainage - Again, we are off grid, the existing bungalow has a cess pit that requires replacement.  We are looking at a sewage treatment plant solution, general consensus seems to be something with minimal moving parts, an air blower type (Bio Pure, Condor, etc).  Our understanding is we will need to get EA sign-off to discharge the treated water into the stream for this solution.  Need to consider placement of the unit so that it is far enough away from the house.

SUDS/Soakaways/Rainwater harvesting - Given we currently discharge rainwater directly into the stream and it's unlikely we'd get permission to continue doing so, we potentially need to look at viability of soakaways (given clay soil), SUDS or rainwater harvesting solutions to offer betterment, we'll need some advice here.

 

So a fair amount that we need to package up, design and get the relevant permissions and approvals.  Does anyone have a view on how best to go about approaching this and could anyone recommend a civil/structural engineer that could assist us with it?  Is there anything I've missed above that we need to consider and design in?

 

We are based in Hertfordshire, is someone local necessary given we already have a soil report or would you suggest local knowledge of soil conditions be significantly beneficial?

 

Any help much appreciated.

 

[jimmyharris80]

Hi guys - Any views on this please?

 

Would it be best to move to another board if not in the right place?

[George]

I've done a few like this. What you've written in this post forms the basis of a decent scope of works so I'd just send off to Civil Engineering companies for quotes.

 

You don't tend to find many one-man band Civil Engineers as it's a bit more specialised and to make money you need to work on very large projects (whereas structural engineers can make money off small projects). All I ever do is provide a framework for a builder to price from but essentially the builder is the one who would be checking levels and getting building control sign off.

 

Also I believe outflow to surface water from a STP won't need specific EA approval so long as it complies with the general binding regulations.