Who would set out site?

[flanagaj]

4 hours ago, saveasteading said:

It has landed on the concrete. That's better than some.

I can picture the reaction to that realisation 

[flanagaj]

I wasted a weekend and a £100 in timber ..   the surveyor chap marked it all out in 2 hours 🙄

[Russell griffiths]

9 minutes ago, flanagaj said:

I wasted a weekend and a £100 in timber ..   the surveyor chap marked it all out in 2 hours 🙄

Does it look right. 

[Mr Punter]

If you can, transfer the survey markings to just outside the building footprint so you can easily run a string line down the centre of the trenches and re-mark.

[flanagaj]

1 hour ago, Russell griffiths said:

Does it look right. 

I’ll be out with my tape measure later, but I’ll be very disappointed if it’s not 😂

[JohnMo]

53 minutes ago, flanagaj said:

I’ll be out with my tape measure later, but I’ll be very disappointed if it’s not 😂

Check the diagonal dimensions to make sure it's square, you have nice oblong building so should be easy to get right, but ...

[saveasteading]

10 minutes ago, JohnMo said:

measure later

later so that they don't feel threatened/ doubted, and so you have lots of time to get the hang of it.

 

I think you said the site is sloping. The tapes need to be tight and horizontal.  if necessary use a spirit level to bring one point op to the level of the other.

Then don't panic if it is a few mm different. the diagonals exaggerate any differences and you have more opportunities for precision as you come out of the ground.

[flanagaj]

2 hours ago, saveasteading said:

later so that they don't feel threatened/ doubted, and so you have lots of time to get the hang of it.

 

I think you said the site is sloping. The tapes need to be tight and horizontal.  if necessary use a spirit level to bring one point op to the level of the other.

Then don't panic if it is a few mm different. the diagonals exaggerate any differences and you have more opportunities for precision as you come out of the ground.

Would you still check even though it was set out with a total station?

 

some of the pins are not vertical, so that will skew the diagonal measurement.

[Redbeard]

38 minutes ago, flanagaj said:

some of the pins are not vertical, so that will skew the diagonal measurement.

 

But surely the hole will be in the right place

[Russell griffiths]

Now you have your pins in place you could set up your profile boards if you want, you can mark external wall and internal then see it all drops onto the foundation. 
are you going 600 wide or 700. 
im sure something changed recently regarding regs. 

[saveasteading]

3 hours ago, flanagaj said:

Would you still check even though it was set out with a total station?

 

some of the pins are not vertical, so that will skew the diagonal measurement.

Yes I would, because people make mistakes.  

Presumably the  pins are  in the ground at the exact spot, so you measure to that, or to a spirit level up from it.

Also check any critical distances, for example to an existing feature or a boundary. 

 

I would also do as I said earlier and take references, but it is up to you.

This is in case a pin is knocked over.

 

It is simple to place offset pins or pegs. 

Project the wall lines you have, and put a mark in 1m (typically) beyond, at each end. If using a peg, put a nail in the top.

You then have 8 pegs. If you wish , tie an orange stringline between them and you have your rectangle, increased by 1m.

Then the digging can all be within that, and you have an immediate check.

 

you may also be saving a visit or 2 from the total station.

[flanagaj]

So there has been a cock up.  It’s been marked out with a 100mm cavity instead of a 150mm cavity.  I’ve just raised this with the surveyor and he tells me that the Dwg file that I provided him showed a 100mm cavity instead of a 150mm cavity.

 

How do people managed to xxxx up the most basic tasks.

Edited 13 hours ago by flanagaj
Corrected measurements

[JohnMo]

You may need to edit replay 350mm or 150mm?

[saveasteading]

7 minutes ago, flanagaj said:

he tells me that the Dwg file that I provided him showed a 100mm cavity instead of a 150mm cavity.

So change it / get it changed.

He can use the correct drawing next visit.

Meanwhile, you have a rectangle marked out too small by a known amount. So you can prepare the area.

 

Perhaps postpone that concrete pour.

 

11 minutes ago, flanagaj said:

How do people managed to xxxx up the most basic tasks.

It's not simple, as you are finding.

[ToughButterCup]

On 15/03/2026 at 23:41, saveasteading said:

...

And that many builders assume that by using lasers there will be no issues.

 

Thats how we found out that the guy who set out our plot made a one meter error.

So I paid him £1 less than he charged.

(But bought him a pint in the pub)

[saveasteading]

4 hours ago, flanagaj said:

I’ve just raised this with the surveyor 

How did you notice the error?

[flanagaj]

27 minutes ago, saveasteading said:

How did you notice the error?

I went out yesterday evening to sanity check the pin spacing measurements and they were around 50mm greater than my cavity centre calculations.  So I then contacted the surveyor who confirmed that his drawings showed a 100mm cavity.  Architect then apologised for sending over an old drawing which showed 100mm cavity.  This was from when we were going to have a 100mm cavity and use 90mm PIR.

 

so I’ve now taken the afternoon off work to validate and move the pins.

[SteamyTea]

Re taking diagonal measurements.

Quick sketch below show what one, half degree out, but correct length does.

 

[saveasteading]

3 hours ago, flanagaj said:

for sending over an old drawing

Good job you found it now rather than when the walls missed the foundations.

It might be worth a spring clean, and delete (or hide away) all the drawings you have and get the architect to send new, clearly labelled  'construction issue'.

Then issue them to anyone else who might need to change them.

 

I have a warm glow from suggesting you check it in the twilight. "Yes I would, because people make mistakes." Let this be your mantra throughout.  This all maters much more to you than to them.

 

@SteamyTea your drawings are a great explanatory.  In real life, I was going to say that the error would not usually be in having a non-square corner as a starting point. But with every little builder now having a Lidl laser, I guess that is quite likely.

[saveasteading]

Just now, saveasteading said:

get the architect to send new, clearly labelled  'construction issue'.

I once had to work with a client's architectural technician who wrote "latest" in the box labelled 'issue'. 

 

I thought he was winding me up but no, it was what he always did.

 

[JohnMo]

9 minutes ago, saveasteading said:

architectural technician

That maybe the issue (haha) - technician, not an engineer.

[SteamyTea]

26 minutes ago, saveasteading said:

  In real life, I was going to say that the error would not usually be in having a non-square corner as a starting point

Was more to show how easy it is to be 50mm out.

In real life the problems are accumulative errors and systematic errors.

Get two workers with their own tape measures and errors can be quite serious even over a few metres.  I never trust tape measures, they are only good for relative reference, withe the relative reference being themselves.

 

Somewhere at home, in my vast library of mathematic's books, I have one a about using a rule and compass to establish mathematical concept. Shall see if I can dig it out and find some relevance to absolute geometric referencing.

[SteamyTea]

13 minutes ago, JohnMo said:

That maybe the issue (haha) - technician, not an engineer.

Isn't an engineer the man that fixes your washing machine in the UK.

Chartered Engineers are what are really needed.

[JohnMo]

11 minutes ago, SteamyTea said:

Isn't an engineer the man that fixes your washing machine in the UK.

Chartered Engineers are what are really needed.

Maybe even the person that empties your bins.

 

Obviously 

38 minutes ago, saveasteading said:

technician who wrote "latest"

had zero idea how to manage drawing revisions.

[SteamyTea]

8 minutes ago, JohnMo said:

had zero idea how to manage drawing revisions

Maybe a tiny bit more understanding than the recipient of the drawing/file.

The problems usually arises 'on the shop floor', not in the drawing/engineering office.

We have similar problems with our food allergy records. We can buy the same product but find that the ingredients have changed. Nothing gets mentioned by the wholesaler or manufacturer. 

It is getting to the stage where we just tell customers that everything has whatever they don't want in it, in it.