Trial pits prior to groundworks, how much £££

[Post and beam]

Hi Guys

Planning documents finally submitted and an advice note from my potential build company that trial pits may be required. Is this the same as a soil survey? How much seems reasonable as i have been given a cost of approx' £6350.

This appears a tad much. As i will be needing an Archealogical survey anyway i would hope that the same hole in the ground could serve both purposes.

Any thoughts?

Regards and thanks in advance as always.

keith

[markc]

That’s madness, digger for a few hours and dig a couple/three holes. These can double up as percolation test holes if organised and located properly.

[ProDave]

To just do trial pits is a very cost inefficient job.  You need to get a digger to site, so that is on and off delivery charges, driver hire for probably half a day all coordinated with when the builder or structural engineer is able to visit.

 

Mine cost nothing as I had already bought myself a small digger, so on the appointed day, the structural engineer arrived, i dug holes where he said as deep as he said, pausing for him to peer down them and look at the spoil coming out.  Then I filled them in again.

 

If you are faced with a £6K estimate, that would pay for a cheap old digger to do it yourself?  then you have it for the duration of the build, then sell it.  It will probably save you money when you get the Archealogical survey done.

[Post and beam]

So is there a recognised spec that 'trial pit'  needs to satisy? 3 holes 1 metre deep at some number of metres apart or such like. I am much happier when i know exactly what it is that will satisfy the requirement.

For the sake of £6k i would dig the bloody things by hand so long as i knew i was not wasting my time.

[jamieled]

Does seem a bit much. For ours, the cost of an engineer witnessing the trial pit was included in the structural design costs so I'm not sure what that part cost, then I paid a local digger driver about 130 quid for a few hours work.

 

I did get a much higher price when asking a professional soils investigation company, but nothing like £6k. Usually just dug until the SE is satisfied, so it depends on the ground a bit - hits something solid and they'll probably be happy with that.

[Kelvin]

Mine cost £600 for trial pits for soil survey, percolation test, soakaway location and survey report. Digger was £50 and a bottle of whisky for a bowser of water. £6k+ is ridiculous. Are they doing something else too? 

Edited December 19, 2022 by Kelvin

[Jilly]

Do you need to be careful where you dig if you need an archeological survey? 

For the record, my first builder charged £400 to dig the trial pits (three holes through an old slab). It couldn't have been specified as it was exploratory.

Edited December 19, 2022 by Jilly

[Miek]

The cheapest hire in digger with a driver is usually a JCB as they are their own transport . Probably minimum hire of 8 hours at around £40 hour. Varies by region a lot.

[Conor]

That's insane, mine was £500 for three pits and engineer supervised. I think you should look at different building forms, because if they are charging that much for a simple dig and report, who knows what they'll charge for anything else out of contract?

 

 

[Post and beam]

I cannot get the Archealogical survey until i have planning permission.  All of my other surveys are done. I think this is becuase the archealogical trenches need to be where the footprint of the house is, which makes sense. I would like to think the same holes will fulfill both this and the trial pit need.

The land is an old orchard and pig small holding. Not had anything on it for at least 125 years other than pig shit and farmers boots. I see no reason to think there would be any issues with foundations for a house.

[saveasteading]

7 hours ago, Post and beam said:

This appears a tad much

No, it is a huge amount. First discuss with SE to see what holes they would want.

If local they will know what ground to expect and the likelh best constriction method. Then 2 or 3 holes, 2m deep is likely to suffice. Jcb, half day including transport.

[bmj1]

We paid £1,050 for a trial pit in London. Pit was specifically to expose neighbours foundations and check their depth, so was dug carefully with hand tools, and then filled in.

 

There was the need to cut neighbour services, and reconnect them, as part of the dig.

 

We did this once equipment was on-site, during construction, rather than separately.

[Blooda]

We paid £3000 - Which I thought was expensive, for Desk Study,  3x 5m core samples, 2 hand dug pits, gas monitoring, groundwater monitoring, Soil tests [organic and inorganic contaminants],  Plasticity index, and water soluble sulphates.  All details wrapped up in a very nice 62 page report.

 

 

[bmj1]

7 hours ago, Blooda said:

We paid £3000 - Which I thought was expensive, for Desk Study,  3x 5m core samples, 2 hand dug pits, gas monitoring, groundwater monitoring, Soil tests [organic and inorganic contaminants],  Plasticity index, and water soluble sulphates.  All details wrapped up in a very nice 62 page report.

 

 

 

A bargain at £48 / page !

[Kelvin]

How much of the report was standard canned text and how much was actually written specifically for your plot…

[Mayebrook]

Can anyone help us and recommend a company in London, our main contractor just quoted us 38K for 5 pits and some openings in the ceiling, this seems outrageous.

[Canski]

That seems a tad over the top. 

[Gus Potter]

4 hours ago, Mayebrook said:

Can anyone help us and recommend a company in London, our main contractor just quoted us 38K for 5 pits and some openings in the ceiling, this seems outrageous.

Yes loads of folk here on BH will be able to give you pointers.. and maybe save you lots of money.

 

But to get the best out of BH you'll need to give us a lot more info so we can all mull it over and give you targeted feedback that applies to your site.

 

 

 

 

[Dave Jones]

On 19/12/2022 at 19:19, Post and beam said:

So is there a recognised spec that 'trial pit'  needs to satisy? 3 holes 1 metre deep at some number of metres apart or such like. I am much happier when i know exactly what it is that will satisfy the requirement.

For the sake of £6k i would dig the bloody things by hand so long as i knew i was not wasting my time.

 

no.

 

The SE is on site.

 

Hole is dug, 10 mins. SE peers in mulls the crap maybe  puts sample in jar and leaves.

 

Digger is collected.

 

You can hire a 5 ton digger for £300 a week from GAP.

 

[ToughButterCup]

On 20/12/2022 at 18:59, Kelvin said:

How much of the report was standard canned text and how much was actually written specifically for your plot…

 

Brilliant question. It's the key question to ask.

 

So many tasks in house building are repetitive and simple. And that tempts so-called professionals to cut and paste text from one specification to the next.

 

On our build two or three times a principal merely signed off a piece of work that was done by a junior member of staff. And in one case that error caused a fortnight's delay and cost quite a bit of money.

 

The quotation that you've been given appears to me to be more about expectation management than a sensible evidence-based costing

 

 

Edited May 13, 2023 by ToughButterCup

[Pocster]

Yeah I was going to be stung for ‘ soil samples ‘ also . Many K

So I dug 3 holes by hand to the required depths . Bagged up 3 handfuls of soil in each . Took them to the lab in town and got the report . I think total cost under 500 quid 

[ToughButterCup]

28 minutes ago, pocster said:

.... Bagged up 3 handfuls of soil in each . .....

 

Any glass in that sample ...  eh? 

[Pocster]

2 hours ago, ToughButterCup said:

 

Any glass in that sample ...  eh? 

Ooooooo ouch ! Nasty Saturday it is ! 😎