Who would set out site?

[flanagaj]

So armed with profile boards, Pythagoras theory ... My wife and I attempted to set out the profile boards for our house this weekend.  The net result of our efforts was zero and we've concluded that it's beyond our capabilities and just too risky to get wrong.  If it was a small footprint on flat ground, then it would be fine, but we've got a 450mm height delta between the attached garage and the house.  Plus, the house is 24m x 7m, which means the slightest discrepancy on any of the angles will result in a significant error.

 

So I'm now wanting to know what specialist I need to employ who can accurately set out the building, eg, mark the position of all internal and external walls and also erect timber profile boards.  If anyone can recommend anyone in Hampshire then can you message me.

[Nickfromwales]

You need a setting out agent / engineer, and just get them to peg the site.

 

You need a dumpy site set out laser and receiver + staff for inverts etc.

 

Use the laser to mark out TOC (top of concrete or DPC) and then transmit this level to a metal post or tree or fence post etc so you know you can always use that as TOC + 1000mm; helpful later on when you start removing spoil and you get lost when your reference points have vanished all of a sudden.

[Russell griffiths]

We had a local surveyor, he came to site 3 times. 
 1. rough set out.  footprint plus 2 m in all directions so we could strip the site. 
2. Accurate footing set out, footings set out with metal pins on every corner accurate to 20mm in any direction 

3. Wall set out, masonary nails put into footing concrete on corner locations, accurate to the mm. 

[flanagaj]

1 minute ago, Russell griffiths said:

We had a local surveyor, he came to site 3 times. 
 1. rough set out.  footprint plus 2 m in all directions so we could strip the site. 
2. Accurate footing set out, footings set out with metal pins on every corner accurate to 20mm in any direction 

3. Wall set out, masonary nails put into footing concrete on corner locations, accurate to the mm. 

This is really helpful.  I hadn't thought about multiple visits and assumed they just came once to set out and that was it, but it makes complete sense for them to mark the concrete footings for the exact location of the wall position.

[Nickfromwales]

7 minutes ago, flanagaj said:

This is really helpful.  I hadn't thought about multiple visits and assumed they just came once to set out and that was it, but it makes complete sense for them to mark the concrete footings for the exact location of the wall position.

You need to mark out a bigger area, as you’ll need temp hard standings for most scaffold companies to put their stuff down on to. Also, you need that perimeter for the stubs of pipes / ducts that get left projecting until you dig back out for groundworks / drainage / services etc. 

[flanagaj]

6 minutes ago, Nickfromwales said:

You need to mark out a bigger area, as you’ll need temp hard standings for most scaffold companies to put their stuff down on to. Also, you need that perimeter for the stubs of pipes / ducts that get left projecting until you dig back out for groundworks / drainage / services etc. 

I've already had the site levelled 200mm below finished floor and 1m wider than the dwelling.  

[Russell griffiths]

1 minute ago, flanagaj said:

This is really helpful.  I hadn't thought about multiple visits and assumed they just came once to set out and that was it, but it makes complete sense for them to mark the concrete footings for the exact location of the wall position.

I haven’t seen profile boards used in years. 
they take your drawing and load it into their computer in the office, when they come to site it is all loaded into their total station all ready. 
they use a glass prism on the concrete footing that gets the accuracy bob on. 
get them to put a height post in, you can mark it with ffh and all the other things you need on it. 

[saveasteading]

29 minutes ago, Russell griffiths said:

all loaded into their total station

That is likely. That way or using tapes and triangulation  doesn't matter.

 

Please remember that they will mark stuff out and the very next operation is digging it all out again.

So either they or you should provide reference points that you can refer back to. throughout the process, so that they dont have to repeat the operation.

these can be offset pegs from their references, usually 1m parallel to the  grid lines.

Plus you can measure to permanent features such as fences or poles. a nail into these is good as it stays put and will hold the end of  a tape.

 

We can discuss that more after. and triangulation.

If using a builder then you should discuss what they need from you, and what they will do if they dig out or knock over an markers.

 

RE slopes, if you hold a tape horizontal, and pull tight then the slope difference is removed. The fact that you recognise this is very encouraging and you probabaly wouldn't believe how few do.

 

Buy a 5m steel tape and a couple of 30m fibre tapes by recognuised brands.  I once had 2 x steel tapes, 'silver something or other',  from SF that were inaccurate 100mm over 30m! that could have been very expensive.

 

[Oz07]

I've always used profile boards and triangulation. Tbf on the last one my laser marked the first 90deg so just double checked with the tape and all was good. Once you've got profiles for your two longest walls its easy. I could talk you through how to do it but might be better off with engineer if not confident. Its probably a mugs game anyway takes a day and usually best to have 2 people. Bet it works out cheaper to pay a pro. I'd love to have a go on one of those total stations and see how they work it must be like magic. How do they compute if site boundaries not as per OS maps?!

[Oz07]

1 hour ago, saveasteading said:

That is likely. That way or using tapes and triangulation  doesn't matter.

 

Please remember that they will mark stuff out and the very next operation is digging it all out again.

So either they or you should provide reference points that you can refer back to. throughout the process, so that they dont have to repeat the operation.

these can be offset pegs from their references, usually 1m parallel to the  grid lines.

Plus you can measure to permanent features such as fences or poles. a nail into these is good as it stays put and will hold the end of  a tape.

 

We can discuss that more after. and triangulation.

If using a builder then you should discuss what they need from you, and what they will do if they dig out or knock over an markers.

 

RE slopes, if you hold a tape horizontal, and pull tight then the slope difference is removed. The fact that you recognise this is very encouraging and you probabaly wouldn't believe how few do.

 

Buy a 5m steel tape and a couple of 30m fibre tapes by recognuised brands.  I once had 2 x steel tapes, 'silver something or other',  from SF that were inaccurate 100mm over 30m! that could have been very expensive.

 

Thats insane 100mm on 30m was it stretching or was it just always 100mm out on the markings on the tape?

[Oz07]

@flanagaj if I remember isnt your footprint just a long rectangle? Should be easy to diy mark if so.

[Russell griffiths]

2 hours ago, Oz07 said:

I've always used profile boards and triangulation. Tbf on the last one my laser marked the first 90deg so just double checked with the tape and all was good. Once you've got profiles for your two longest walls its easy. I could talk you through how to do it but might be better off with engineer if not confident. Its probably a mugs game anyway takes a day and usually best to have 2 people. Bet it works out cheaper to pay a pro. I'd love to have a go on one of those total stations and see how they work it must be like magic. How do they compute if site boundaries not as per OS maps?!

I don’t think the os map has much to do with it. 
site TOPO survey taken at beginning of project then all drawings laid over the TOPO. 

[flanagaj]

I've actually found a surveyor in Southampton who is coming out tomorrow afternoon to mark it out with a total station.   Given the cost and associated implications of getting it wrong, it's a no brainer.

[G and J]

We’ve a 26m x 6m house.  It’s not a simple rectangle but it’s not a silly shape either. 
 

We’ve odd foundations as our walls sit 35mm from the outside edge of the founds, so foundations position was unusually critical.
 

We used profiles (meaning odd bits of timber screwed into stakes, and then screws placed for string lines).  if you place the profiles sensibly they won’t get dug up and will keep you true. 
 

To set out the profiles we used tapes.  My oppo isn’t a Pythagoras type of guy but he does know his 3-4-5.  (I know, I know).  
 

It’s the kind of thing that might take a couple of goes if it’s your first time. But actually, it’s fiddly but not that hard.  You can do this if you want to. 

[saveasteading]

5 hours ago, Oz07 said:

Thats insane 100mm on 30m

It wasn't stretching , simply very inaccurate.

I can't remember  how I discovered the problem. Probably used a different tape.

 

 

I got my money back of course but refused to return them in case they sold them again, and binned them. Good fibre tapes are now very accurate IF stanley etc.

 

2 hours ago, flanagaj said:

it's a no brainer.

That's great, but you do need to take references off it, or you'll have that great price 5 times.

 

[saveasteading]

2 hours ago, Russell griffiths said:

don’t think the os map has much to do with it. 

Agreed. Your physical boundaries are what matters and seldom as OS, or even Land Registry shows. 

 

I won't bore you with my stories and cross my fingers for you that the project fits in the space available.

[saveasteading]

5 hours ago, Oz07 said:

I'd love to have a go on one of those total stations 

You can have mine.

I was brought up on theodolites and tacheometers when simple total stations were just invented. We were told that without using the manual machines we wouldn't understand the full implications of the built-in inaccuracies and geodetics. That is true.

 

The worst setting-out I ever saw was by a guy who claimed to have been a surveyor on Eurotunnel.  Using a total station he set the rectangular  building out with splayed sides...  so wrong that eyeballing or  pacing were much more accurate.

 

It's quite a skill using a total station. Under some staff pressure I bought one at great expense. Nobody used it and we carried on using tapes.

 

Anybody want a Leica Total Station? Was £14K, I'll settle for 2 as it's quite old but barely used.

 

 

 

[saveasteading]

23 minutes ago, G and J said:

might take a couple of goes if it’s your first time. 

I've come to realise that you can either do this or you can't. 

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

[Oz07]

6 hours ago, saveasteading said:

You can have mine.

I was brought up on theodolites and tacheometers when simple total stations were just invented. We were told that without using the manual machines we wouldn't understand the full implications of the built-in inaccuracies and geodetics. That is true.

 

The worst setting-out I ever saw was by a guy who claimed to have been a surveyor on Eurotunnel.  Using a total station he set the rectangular  building out with splayed sides...  so wrong that eyeballing or  pacing were much more accurate.

 

It's quite a skill using a total station. Under some staff pressure I bought one at great expense. Nobody used it and we carried on using tapes.

 

Anybody want a Leica Total Station? Was £14K, I'll settle for 2 as it's quite old but barely used.

 

 

 

If I can wrap my head around how they work I'd consider it. Whereabouts in the country are you?

[Oz07]

9 hours ago, Russell griffiths said:

I don’t think the os map has much to do with it. 
site TOPO survey taken at beginning of project then all drawings laid over the TOPO. 

Ah I didn't know how they load the original map I assumed it was os. Round here the councils still dont require topo as part of planning so you can just say dwelling 150mm above finished ground or x mm above ffl of adjacent house. 

 

When I'm setting out I just pick whatever my most important boundary is and go of that. If the house is shown 5m off the front for instance I'd pick that and if its a hundred or couple of hundred mm different at the back due to boundary features not tallying up then so be it. 

[Oz07]

6 hours ago, saveasteading said:

It wasn't stretching , simply very inaccurate.

I can't remember  how I discovered the problem. Probably used a different tape.

 

 

I got my money back of course but refused to return them in case they sold them again, and binned them. Good fibre tapes are now very accurate IF stanley etc.

 

That's great, but you do need to take references off it, or you'll have that great price 5 times.

 

Are fibre more accurate than steel then? I always assumed the opposite. Don't tapes have different grades of accuracy? Like a, b, c etc?

[saveasteading]

1 hour ago, Oz07 said:

Are fibre more accurate than steel then? I always assumed the opposite. 

In the past, fibre was elastic and only for rough work, and you learnt how tightly to pull it. Steel was accurate but vulnerable to damage and rust, and even temperature affected for precise work.

New fibre tapes are accurate, and  ,as you say, in different grades... clas 1 or 2 will do.

Open reel fibre is best for groundworks stages

 

I see SF sell class 3 own brand for £10. But Stanley for £20 looks my choice.

 

[SteamyTea]

17 hours ago, Russell griffiths said:

accurate to the mm

Think I need to lay down in a darkened room.

 

[saveasteading]

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

[Russell griffiths]

2 hours ago, SteamyTea said:

Think I need to lay down in a darkened room.

 

Look for the nail !