Ground investigation

moldy_sea

Context is one off build of 2 story, 3 bed house, Dublin city.

What process have others followed with respect to ground investigations prior to starting building?

Is there a low to high effort approach? e.g. a professional does a desk exercise in combination with a visual on site inspection - maybe that's enough, maybe not and some excavations are carried out and soil sent for analysis.

Is there a standard approach?

Calahonda52

Is the site serviced for sewerage?

Metric Tensor

Cheap method: Dig a hole and have a professional look in.

Expensive method: Dig multiple holes and carry out boreholes and or tests. Have professionals watch and review.

Irish method: Dig no holes and take a chance on costs until you start digging for foundations.

BryanF

moldy_sea wrote: »

Dublin city.

brown or green field site?Have you an engineer? Whoever is design the foundations will be doing this

moldy_sea

Calahonda52 wrote: »

Is the site serviced for sewerage?

Not yet but sewer within 5m

Gumbo

BryanF wrote: »

brown or green field site?Have you an engineer? Whoever is design the foundations will be doing this

This.

MT can confirm, but should the Engineer carry out a GIR to determine the design of the foundations and also the structural sub floor material fill?

T0-T3 etc

Metric Tensor

The engineer should satisfy themselves that the ground is capable of supporting the load that will be put on to it. This can be pretty simple using trial holes and some small tests for lightly loaded structures or pretty advanced for large or bespoke structures. Along with some desk research (or local knowledge as it might be more commonly known) some engineers may even be confident for small strcutures based on a visual inspection.

Separately from this, the engineer has to design the foundation, which is the means by which the load is passed into the ground. This can take many forms depending on ground strength, conditions and applied load but is generally made of up some from of concrete, steel and back-filling material. There are specific very tightly coded regulations for all of the above materials and how the should be put together, what types should be used and how they should be tested. (This is where kceires T0-T3 designations, above come into things.)


Mind you some alleged building "experts" would laugh at the above and tell you that they've been doing it X way for many years and roll out my old favourite line: "Not one of my buildings has fallen down yet" - followed by a hearty guffaw and some choice language about engineers. I hate to give this type of sh!te talk any time but experience does count for a bit in building - HOWEVER if said "expert" was asked for a letter confirming the foundation complied with the building regulations and a copy of their insurance to cover that assertion it might not be forthcoming!