Setting out

[vivienz]

Our site is bordered by a wiggly little rural lane and so there's no chance of taking a reference off this for the location and layout of the new build.  The groundworker needs to dig out for the piling system as well as the slab foundation so I need to make sure that everything is the right size and in the right place.

 

I'm assuming that I need a surveyor to do this, which will cost me a few quid, unless anyone can come up with a genius, money-saving alternative.  Also, do I need them to set out in 2 stages, i.e. first for the piles, then again for the foundations?

 

 

[Declan52]

On the plan is there an entrance marked. Scale of this point to the nearest corner. You will need to use points both sides of the entrance to the same corner to give you an accurate measurement.

The rest is just using Pythagoras to get you your corners. Once it's roughly set out as 4 corners then you can see how it sits and move it whatever way you need to.

You will need a big metal tape measure, won't stretch like a plastic tape, wooden stakes and string line. And another pair of hands.

It's not hard to do but will take a few hrs and a few different positions to get it where it finally needs to be.

[vivienz]

A good job for next weekend - thanks, Declan.

[epsilonGreedy]

I am at a similar stage and considering diy setting out to save £500. My house position is also vague with nothing substantial available for precise positioning of the footings.

 

I have two hedges, a lane, another ancient property about 15 meters away and one new house 30 meters away in-build. The local planning officer told me they don't resort to enforcement when the position is less than 0.5m out. My house also has an interesting rotation 10 degrees different to the building-line alignment of nearby properties, so I plan to reference a solar azimuth table and align the front elevation to a shadow at the right time of the day.

 

I have done multiple trial set outs of the foundation plan by resorting to school boy trigonometry, the bit that worries me is "levels". I don't get all the mystique about levels but have 3 weeks to get my head around the subject.

 

Everyone in the building trade assumes I will be paying an expert to obtain laser calibrated "levels", this feels like overkill considering the max fall across my footings is 250mm.

 

Easy visual trigonometry can be done at this web site, it is preferable to scaling up from 3,4,5 triangles:  https://www.visualtrig.com

 

p.s. Do all you trigonometry diagonal length calculations back home on a desk, it is too much bother to fiddle with a trig web site at the plot on a sunny day.

Edited May 29, 2018 by epsilonGreedy

[Declan52]

Can you get a string line from the base of the new house to yours with our any thing fouling it???

 

[epsilonGreedy]

1 hour ago, Declan52 said:

You will need a big metal tape measure, won't stretch like a plastic tape, wooden stakes and string line. And another pair of hands.

It's not hard to do but will take a few hrs and a few different positions to get it where it finally needs to be.

 

 

I used metal tent pegs for my trials runs as these were easy to remove and so no opportunity for an ambulance chasing fraudster to claim wooden pages were a source of hazard and injury.

 

I also found it was better to focus effort on marking out a large accurate rectangle that enveloped the whole house and then mark out more fiddly footing details with reference to this master outer box. The alternative is marking out one box relative to an adjoining box but I found this led to errors.

[epsilonGreedy]

2 minutes ago, Declan52 said:

Can you get a string line from the base of the new house to yours with out any thing fouling it???

 

 

Yes no problem.

 

The cooperative pro builder of that plot also suggested I get my levels from his now that he has done the leg work of finding a substantial local reference for his setting out. Safety in numbers I suppose.

[Declan52]

Happy days then. If your build is near enough the same height as his then just use his.

[Gone West]

35 minutes ago, vivienz said:

A good job for next weekend - thanks, Declan.

Yes, it's not too difficult. We did the setting out and levels for our foundations. I used a lot of short lengths of reinforcing rod, a steel measure and the 3,4,5 triangle rule.

[Russell griffiths]

I suppose this all depends on what you value your time at and what you think is expensive 

we are having piles so have to drop levels to provide a level area, surveying team are on site tomorrow, estimated to take about an hour @ £75 

 

we are then having them back to plot the pile locations 

once the piles and ringbeam are in they come back again to stick a nail in at each corner location 

3 site visits estimated cost £350

 

if you are piling has your piling guy not specified that pile locations will be set out as per drawing before they come to site

it worked out cheaper for me to get my surveyors to plot pile locations rather than him do it. 

Im an ex brickie and I wouldn’t want to do mine, I suppose it also depends if your house is fairly regular or has lots of in and outs. 

[vivienz]

Useful comments, thanks Russell.  I haven't had much other than 1 quote from a surveyor so far, and they want £450 +VAT for the visit to set out for the piles, then another £450 + VAT for the foundations.  It seems rather expensive to me, in truth, but then the positions of the piles is rather important to everything that comes afterwards.

[Russell griffiths]

What you want is the closest company to your plot,mine can be on site in under 10 mins from there office

putting the pins in for the piles is very straight forward so any good site surveying co will be more than capable 

so look for the closest 

they will all be reading the same drawing, and if you have a copy you can follow with a tape and check a few, I will be?

[ToughButterCup]

3 hours ago, vivienz said:

[...]  The groundworker needs to dig out for the piling system as well as the slab foundation so I need to make sure that everything is the right size and in the right place.

[...]

and

3 hours ago, epsilonGreedy said:

I am at a similar stage and considering diy setting out to save £500. My house position is also vague with nothing substantial available for precise positioning of the footings.[...]

 

Don't even think of it where piling is concerned.

The consequences of putting  piles in the wrong place (as a result of inaccurate setting out) are substantial. A surveyor with a Total Station will get it right to within 3mm. 

 

The first thing the piling company will want to see is an accurate plan and soil profile. The risks associated with errors at this stage are significant.

 

Check the survey yourself by Pythagoras by all means.

 

PS our piler had it's own GPS equipment:  they double checked our setting out.

[mvincentd]

I agree that you shouldn't initially diy in your situation. Luke SE will likely recommend Baypoint...charged me 350 per visit.  They may suggest you'll need numerous visits,  but once your piles are set it might be more viable to go diy thereafter.  If Keith were to offer, for the pittance that might save you I wouldn't entrust the task to him (no disrespect).

[CC45]

Get someone in with a Total station.  We did twice - footings set out (sprayed on ground) and then again to mark out the corners of the house.  No stings / profile boards etc.  Simple and well worth the cash.  You might find someone who wants a few hours at a weekend - for cash.  Plenty of opportunities to save cash in the future.  Get this detail right - its important.

[vivienz]

Thanks chaps. I shall use a professional. Interestingly, Mike, Baypoint are quoting £450 + VAT per visit. I'm sure that inflation hadn't been that high since yours was set out. Many of the quotes obtained via the architect have been inflated and this seems to be no exception.

 

[ToughButterCup]

6 hours ago, vivienz said:

[...]

Many of the quotes obtained via the architect have been inflated and this seems to be no exception.

 

It's part of the game. The antidote is networking. With the emphasise on working.

[nod]

12 hours ago, vivienz said:

Our site is bordered by a wiggly little rural lane and so there's no chance of taking a reference off this for the location and layout of the new build.  The groundworker needs to dig out for the piling system as well as the slab foundation so I need to make sure that everything is the right size and in the right place.

 

I'm assuming that I need a surveyor to do this, which will cost me a few quid, unless anyone can come up with a genius, money-saving alternative.  Also, do I need them to set out in 2 stages, i.e. first for the piles, then again for the foundations?

 

 

The setting out is a very important part of your build If you are not familiar with setting it is better to get a surveyor in 

The money you will save is quite a small amount and can be swallowed up if you are a little bit out 

[mvincentd]

8 hours ago, vivienz said:

£450 + VAT per visit

Blimey, my last invoice from them at £350 is only a year old.  Might cut no ice but feel free to tell Stuart you came to him on my recommendation and price guide so are 'surprised'.....i do vaguely recall him demonstrating a bit of flexibility.

[Nickfromwales]

13 hours ago, vivienz said:

Useful comments, thanks Russell.  I haven't had much other than 1 quote from a surveyor so far, and they want £450 +VAT for the visit to set out for the piles, then another £450 + VAT for the foundations.  It seems rather expensive to me, in truth, but then the positions of the piles is rather important to everything that comes afterwards.

One member on EB had the piles done, and then they were cut off very neatly and perfectly level and flat, and the ring beam all done very well........all 600mm too low in the plot !!! So low in fact that they nearly had to lose gravity sewers and fit a pumping station. 

CHECK, CHECK, and CHECK AGAIN. 

Know your levels before your guy gets there, know your ridge and finished slab height, and question EVERYTHING and EVERYONE. A few have fallen foul of assuming that paying someone is a guarantee of nothing going seriously wrong. Ive heard some utter horror stories where this has been the case. 

Having a turnkey package ( downstream of this ) gives you recourse against such failings and a means to seek remedial action, but its better to not have had them in the first place. Your still only dealing with human beings after all.   Tape measures and lasers are cheap to buy / borrow / hire.

For me, I'd need to know this part of the process as well as the person I'm paying to do it. 

[Ian]

+1 to what @Nickfromwales just said. I was involved with a large commercial building where the 'professional' main contractor set the ring beam too high which meant it interfered with the planned gravity foul drainage runs from a lot of showers located in the ground floor slab next to the ring beam. They had to pay for special low profile trap connectors to be made to get around the problem.

[vivienz]

2 hours ago, mvincentd said:

Blimey, my last invoice from them at £350 is only a year old.  Might cut no ice but feel free to tell Stuart you came to him on my recommendation and price guide so are 'surprised'.....i do vaguely recall him demonstrating a bit of flexibility.

I've just checked and their quote was actually for £475 + VAT per visit!  Definitely a case of hyper-inflation on the south coast.  Grrr!

 

Seriously, though, it does seem to be a common theme that anything coming via the architect has the south coast premium plus a bit attached to it.  This isn't due to the architect trying to add a slice to anything, more the other associated trades and professionals seeming to think that if an architect has been used, there is idiot money up for grabs.

[ToughButterCup]

1 hour ago, Nickfromwales said:

[...] 

CHECK, CHECK, and CHECK AGAIN. 

Know your levels before your guy gets there,

[...]

For me, I'd need to know this part of the process as well as the person I'm paying to do it. 

 

I found an exact one meter error (in the placing of one marker)

 

Its a bugger when you  pay people to make mistakes for you and then have to check for yourself. But that's this self-building game.

A snagging retainer works well too.

 

So far I have (on the basis of evidence) retained £9600. And not a peep  from the contractors whose work has needed remediation. 

[Russell griffiths]

So I learnt something new today

i had the surveying team out to do a rough site layout so I can lower the levels for the piling rig

everything ok 

so I asked them to check a peg  I had banged in with my finished floor level on it

it was 45mm out. WTF

After a minute of trying to work out what was wrong it turned out that due to poor signal from their GPS they where working with a 40mm tolerance, this is standard practice unless they are told they need to be more accurate. 

 

Im actually talking about height above sea level here rather than accuracy between to points. 

[Nickfromwales]

On 30/05/2018 at 17:19, Russell griffiths said:

So I learnt something new today

i had the surveying team out to do a rough site layout so I can lower the levels for the piling rig

everything ok 

so I asked them to check a peg  I had banged in with my finished floor level on it

it was 45mm out. WTF

After a minute of trying to work out what was wrong it turned out that due to poor signal from their GPS they where working with a 40mm tolerance, this is standard practice unless they are told they need to be more accurate. 

 

Im actually talking about height above sea level here rather than accuracy between to points. 

Its been said a few times here that a difference of 100mm or so in ridge height would not be argued by Planners.