Foundations are dug now how do I put the stakes in level?

[Danturboc]

Hi I have just had my foundations dug today and just finished off tidying the edges up ready for concrete.

Now I need to put the wooden stakes in now but not sure how to get them level all the way round is there a specific way of doing this?

Here's some pics:





The trenchs were meant to be 500x450 wide but they have got abit bigger in places but not too bad. So at the top right corner the trench is abit higher up than the rest, that is the highest point.

So how would I get the stakes all the same height all the way round, any infor would be great cheers

 

[bernardgreen]

Using a water theodolite works well enough.

Instruction here http://www.instructables.com/id/-WATER-TUBE-LEVEL-from-scraps-/

 

[Danturboc]

Just had a look at that, would that really work? Would need to be a long tube!

 

[stuart45]

Use a level and 6ft straight edge.

 

[Danturboc]

So as the trench floor is at its highest point at the top right corner would you start there and level it all to that one? So set that one at the 300 which is what I want and then just level the others to that which will mean at some places it will have more than 300 concrete in to meet that level but that's not a problem

 

[stuart45]

Set some pegs at DPC level so you can measure down and get the bricks/blocks to work easy courses, but start at the highest as you said if you want a minimum thickness.

 

[vinn]

I take it that you know what level datum you want for DPC and FFL's etc? That you have a reference point for the concrete surface?
If so, simply drive stakes at the trench corners and in-between positions. Use maybe five stakes.
The stakes go into the centre of the trench floor.
The stakes should be proud of the required pour surface by about 200mm to 300mm.
Buy a line level and chalk box (string line) kit for a few quid. The line level hangs from the line.
Level the string line from your reference point and mark each stake at the level required.
Work clockwise and then do an anti-clockwise check.
When the pour is up to the stake marks roughly flatten the surface and then wait.
When the concrete begins to set, smooth off the surface and pull the stakes.
Make good the stake holes.

 

[^woody^]

Pour the concrete in wet. It then more or less self levels.

Rake it, looking at the puddles as a guide to getting it level. If need be, throw some more water on the surface.

Then use a level to finish it off if it still needs more work.

Then trowel or brush it

It's not rocket science, and you don't need a plethora of tubes, stakes, datums and what not.

 

[Danturboc]

Just a thought before I have ago at this Tommorow, is it worth me buying one of these as they are only cheap (I know it's not an amazing make):


Would that make the job allot easier if I had that?

 

[garyo]

Just a thought before I have ago at this Tommorow, is it worth me buying one of these as they are only cheap (I know it's not an amazing make):


Would that make the job allot easier if I had that?

No no they're sh*te! I've tried using one before and they'll easily put 1cm of error over a 5m site. Go for an Egyptian water level on two ends of a hose pipe if you really want to stake it, cheap as chips on eBay. I'd go with the puddle method: chuck it in and the water comes to the top... let the puddle be your spirit level.

 

[noseall]

It's not rocket science, and you don't need a plethora of tubes, stakes....

A staked trench is valuable in particular if you are having it supplied ready-mixed in quantity. Too much concrete is a pig to shovel out. Concrete will shrink down the pegs and it also stays raised at the sides leaving it dished towards the middle so water will puddle there in any case.

Dicking around with split bricks or heaped mortar is no fun in the Winter either.

Just use a 1200mm level and a straight edge and peg each corner and a say three more on the long runs etc.

 

[bernardgreen]

Too much concrete is a pig to shovel out.

Too true. it was almost 40 years ago but I remember it well.

And concrete does not self level unless it is very wet, in which case it will shrink as it sets and excess water evaporates ( of soaks into the ground ). A good mixture will slump down to something that appears to be level but probably too un-level for the building.

 

[Danturboc]

Ok thanks guys! Gonna go and buy a longer spirit level on my way home from work and give it ago later. Another quick one is there a problem with leaving the trench open for a few days before I get the concrete in? Like it'd it rains will it affect it?

 

[stuart45]

A bit of rain won't be a problem, unless the sides start caving in.

 

[^woody^]

Rain might soften the trench bottom which then will then need scraping.

You should be OK up untill Thursday