ToughButterCup

We are building on a slight slope: I have come to realise that this is a significant advantage in terms of drainage and other issues. Talking to a contractor about how much stone will be brought in, he mentioned that it was something of an art to estimate the amount of stone needed - especially where there's a slope. From my teaching background I know that conservation of volume is one of the last things that humans learn (look at the difference in the designs of pint glasses - some look large, others surprisingly small - even experienced people find it hard to estimate volume) We have had a topographical survey. I have superimposed the piling mat area in red. The image is oriented North-South. You will see there's a cross-fall South East - North West of about a meter. And somewhat less from the North East to the South West. Roughly, it's a lop-sided wedge. If it were a simple wedge, calculating the volume would be easy. But it isn't a simple wedge. I frightened myself silly looking at maths websites in attempt to calculate the volume. I already hear a chorus from over the water about over-thinking. This is just a bit of fun. At worst we'll need a few more loads of stone: tough, suck it up. I'm interested in how to go about calculating that wonky wedge volume. Pointers, please!

And here's the briefest, definitive, well-written guidance I've found which explains the issue in relation to self-builders cdm 2015 - qa 3 self build projects.pdf

Yes. It boils down to a combination of price, rig size, and piling design (in terms of kN per pile). Ian

Yes, exactly, you need to go through that exercise. 'Known unknowns and unknown unknowns' (God, how I loathed that bloke) We are on a small, but noticeable slope. That means that we can accommodate all our post-piling spoil. Might that work for you?

No, @Stones, I imagine they wouldn't probably because the mat needs to take a dynamic stress . And the mat needs to be penetrable by the poker (stupid term for a humungous vibrating crane-mounted ramrod)

@swisscheese - have you noticed we are using 'ground improvement columns' NOT piles, but they appear to most people to be piles so we call them piles - in error. Have a look at this However, the piling mat is the same for both: I think. Notice the difference in the calculations for the depth needed if you use Polypropylene Geogrid Tensar SS20. You might like to ask for the calculations they have done showing the difference made by the grid: in our case 280mm instead of 480mm I do not wish to be seen to be advertising. Stone columns and piles are different beasts. Stone columns are significantly cheaper than steel piles. We have about 52 columns to insert. Start 0930. Finished - off site by 15:00 same day.

OK @swisscheese, to help you, I'll go into detail; Here are the calculation for the depths of the working platform thickness provided by TC Vibro (I'm working with Dan and John Ashton the Contract Manager) PilingMatCalcs.pdf The numbers which interest us are the Required Working Platform Thickness (bottom of page 1). There's one for 'raw' thickness of 0.48m and the other for a piling mat with Geosynthetic Reinforcement , 0.30m What constitutes a piling mat if you need new fill? Here's the answer - again from TC Vibro Specification for Upfill Materials.pdf Are there any guidelines for Piling mats? Of course there are. BR470t.pdf In preparation for this exercise we had a topographical survey done (5 locations) soil sampling 5 locations and a site visit done by Dan from TC Vibro. He asked me to dig a three meter hole in front of him so that he could hold the clay that I dug out. He needed that done in front of him so he could judge the water content. The charges for the rig set up are eye watering (£2.5k per visit) but after that each stone column of stone is relatively cheap. As I explain above -broadly- there's probably no need to get the mat tested. But on balance, why would I not demonstrate good faith to the company when they have visited me three times (Dan twice and the Contracts manager once) to make sure the risk of failure is as low as we can reasonably get? I also visited a site on which TC Vibro were working. In addition I have called out the water board to survey the water pipes (compulsory when piling within 15 meters of a water pipe here), but more honoured in the breach than the observance I think. Luckily, our pipes are cast iron, and a meter below ground level. Can I suggest a bit of care with the crushed concrete spec (see the Up-fill spec attached). Dan informally talked me through some of the poor practice that some contractors do in preparation for the piling mat: the end in mind is making sure the piler (or in our case the 'poker') can get through the mat and the substrate. If the area hasn't been dug to the correct depth, the risk increases. @John Ashton, you may want to comment on the above. @swisscheese, I'd be interested in a bit more detail if you can bear it.....

Exactly. What we're trying to prevent is significant deviation from vertical: the mast is huge; the machine has a limited capacity for self adjustment, though. I've got one informal quote of £400 ish, which to me seems cheaper than the price of having a rig hanging around at £2.5k per day. The setup cost of the rig is £2.5k per day. So, were the rig to sink just a bit more than allowable, I would have to remediate , test properly (to prevent the same problem occurring again) and do it all again. Bang goes £10k if all goes well following a cock up. And easily double that with a bit of bad luck. Yes. And I've been to see it in action, talked to the rig driver, the company contracts manager and the young engineer in person on site. Contrary to some views expressed in this thread, getting this wrong would be a big deal.

Nearly right. The piling mat needs to be right for the machine in terms of the weight it will bear. Also the piling mat needs to be at the correct level. Of course there is an element of common sense to be applied here, but the charges that accrue if I get this aspect of the job wrong are £2500 per day. So for the sake of a couple of hundred quid, why risk the standing charge of £2.5k per day while I get the piling mat sorted out. Perhaps you could explain your comment in a little more detail, please? I, for one, am not sure how to read it - yet-.

Just a quick post to ask if anyone knows the rough cost of Plate Bearing tests? SPONS doesn't list it. Whats a Plate Bearing test? Why do I need it? The pilers won't come on site without one; and if you are using one of these, you can see why. All 37 tonnes of it....

Weekend.... photos to follow

I was thinking (after a few beers) of pimping it with LED floods.... I strapped a couple of rechargeable LED floods to the boom: boy what a difference!

See? I told you.....

One way of annoying a newbie digger driver is to give her a digger and tell her to dig a hole in Lancashire: more accurately the Fylde coast. This what you get: A bucket full of clay - that won't come out of the bucket. Try as I might -swearing-shovelling-crowbarring- Nadda. Nichts. Rien. It sits there looking at you. And then you ask on BuildHub how to sort this problem out and you buy one of these bad boys (bad people) A Clay Spade Hallelujah! This happens... And then when you've stopped swearing and start grinning, a little while later you get to find water..... Out comes the magnet and its ................. CAST IRON. Phhhheeeeeww. I was told by those locals who 'know' that the pipe is asbestos. The man from the Water Board came out, looked at it, sucked his teeth, tapped it, got his ray gun out, zapped it, sucked his dentures some more and said. "Tha's dun me job fer me maaaate. Aye, 'appen, it's awreet is 'at. Pilin', it'll be nay borra, 'appen" and promptly left. With the back doors of his van open and all his tools cascading out onto the road. I nearly wet myself with a mixture of relief and laughter Well, that's that one sorted. Next: piling mat.

Just get MrsPeterM to whisper in your ear. You know it makes sense!

They're on sale at our local garden centre. Look, here's one.

Hello Lauren, A good way for you to get members of this forum talking to you to is to suggest a design, and then ask 'us' what we think of it. For example, let's say you want to have a new brick-built extension - or renovate a brick-built wall. Search the forum using the search engine. Read the posts and the links that have already been made. Then, ask about those aspects that you find interesting. So, if you ask about bricks, then as sure as eggs are eggs, @Construction Channel will reply giving you too much detail about (say) the reason why Flemish Bond bricklaying is the best (or worst), and @Declan52 will tell you about how much the foundations will cost, @Nickfromwales will tell you about the best way to install a wet room, @ProDave will help with the electrics, and @Peter M will help with the best curtain fabric. Welcome! Ian

Hmmm. The architect. Yep, I know......

@joe90, just in the process of getting our windows priced - once all the errors in the Windows and Doors Schedule are corrected - (trickle vents in a passivhaus, I kid you not). So this thread is perfectly timed. 47.66 square meters worth - so thanks @Mr Punter @Stones, @jamiehamy, and @dimpsy for the guide prices. Ian

Ed, there's nowt to be done. Let it go. Don't let him see that his behaviour gets under your skin. Rise above it. People like that are an excellent exercise in self-control. Ian

Knowing me, I'll remember just that little bit too late.... But thanks for the nudge.

I have heard it argued that site clearance does not constitute a 'start'. I'm in a hurry so I can't quite put my finger on it, but there are some threads on here about what a start really is. I think, some LPAs regard a start as digging the water connection or something similar. I have a strong feeling that clearing off the site is gardening , not development. So, you can get the site cleared at least. Good luck! Ian

Is this a pre-condition? Because if it isn't, you don't have to wait.

Yes, right first shot, Dave I'm now planning to find the nearest upstream stop tap (so I can turn it off pronto) dig out round the pipe (vibration doesn't travel so well in air) and cover the pipe with a road plate. The whole piling exercise is going to take no more than 5 hours They're no worse than some of the mega companies we all use. Got to laugh about it though!

Hello, is that the water board? Yes, I need to talk to someone about our piling: the form I need to fill in asks us to tell you about it in advance by ringing this number. Piling? Never Heard of it Well on Form number (xyz), it says to ring your number and ask for someone to come and do a survey Do you want a new connection? Yes, but that's not what I'm asking about, I need to know if someone will come and survey the water pipe, as is the proper procedure according to your form (xyz) Well if you need a new connection Sir, I'll put you through now (CLICK) Hello? New Connections here, hello Sir Hi! I need to talk to someone about our piling: the form I need to fill in asks us to tell you about it in advance by ringing this number. No, Sir, I'm the new connections person, you need Developer Services (CLICK) Hi! I need to talk to someone about our piling: the form I need to fill in asks us to tell you about it in advance by ringing this number. Oh hello mate, we were only just talking to one another - how are ya? Water Boarding: sounds like a good idea to me. signed FURIOUS OF LANCASTER Tomorrow: let's try again eh?