How to make a square corner in a trench?

[Danturboc]

I have the founations done for my garage and not sure how to lay out strings etc.. to make a square corner inside the trench? For the concrete blocks.

I know if I were doing it on the normal ground level I could use wooden stakes into the ground with string etc, but not sure in the trench.

Any help?

 

[stuart45]

https://www.google.co.uk/search?q=b...MAhWFBsAKHTBKBpkQsAQIGw#imgrc=18gCp1ToZ0PnxM:

Use batter boards and drop a plumbline/straight edge down ton mark out.

 

[Danturboc]

Ahh I was searching google for allsorts but nothing what I wanted until you said that.

It makes abit more sense now, will have a read of some of them google posts. I take it the actual batter boards themselves don't need to be anything special just some wood in that shape around each corner, then measure it all with string?

Also once you have used a plumb line to drop to the foundation concrete level, mark the concrete with a chalk line, but surely that chalk line will then be covered with cement when you start your first block so how will you see exactly where it goes?

 

[^woody^]

but surely that chalk line will then be covered with cement when you start your first block so how will you see exactly where it goes

Knock a nail into the concrete

 

[^woody^]

https://www.google.co.uk/search?q=batter+boards&espv=2&biw=1366&bih=667&site=webhp&tbm=isch&tbo=u&source=univ&sa=X&sqi=2&ved=0ahUKEwju46qG4r7MAhWFBsAKHTBKBpkQsAQIGw#imgrc=18gCp1ToZ0PnxM:

Use batter boards and drop a plumbline/straight edge down ton mark out.

Is that a Yank term?

They have always been profiles/corner profiles around here.

 

[stuart45]

Is that a Yank term?

They have always been profiles/corner profiles around here.

It is more of a Yank term, it's profiles round here as well, but if he googles profiles it will probably be more confusing.

 

[stuart45]

Ahh I was searching google for allsorts but nothing what I wanted until you said that.

It makes abit more sense now, will have a read of some of them google posts. I take it the actual batter boards themselves don't need to be anything special just some wood in that shape around each corner, then measure it all with string?

Also once you have used a plumb line to drop to the foundation concrete level, mark the concrete with a chalk line, but surely that chalk line will then be covered with cement when you start your first block so how will you see exactly where it goes?

Spread some mortar along the footing and flatten it with the trowel. You can then mark 2 points with the plumbline each way and use your level to draw a line in the mortar screed. Then just be carefull to lay the blocks to the marks, you can check with the lines from the profiles.

 

[Nige F]

Knock a nail into the concrete

would that be an obo nail?

 

[Danturboc]

I can't tell how serious you are about knocking a nail in the concrete

 

[^woody^]

A masonry nail. We use Hilti nails, but hammer them in.

 

[^woody^]

would that be an obo nail?

It might be ..... if I knew what that was

 

[noseall]

It might be ..... if I knew what that was

A generic term for the old masonry nails. Great fun watching them ricochet off a worn hammer and always towards where your mate is standing.

 

[^woody^]

A generic term for the old masonry nails.

Probably before my time.

 

[noseall]

Use pegs (stakes), lines and a builders 1.2m square. Set up your two longest runs and get them dead parallel. Set up one of the end runs and use the builders square to set the line with the two longest runs.
Set the other short end parallel with the t'uther end. Measure diagonals and adjust if necessary.

The pegs will be outside of the trench, however the lines will (obviously) track over the concrete. Plumb down and scratch or (as said) use spread mortar to make a mark. All you do then is bed a block in each corner and pull a line from one corner block to the next.

Leave your lines up and use them to check (using your eye) how true your walls are to the lines. We like to drop the square onto the concrete (before any blocks are laid) and look from directly above at how the lines tally up with the square. It's easier than trying to hold the square level with the lines - too fiddly.

 

[noseall]

TOP TIP:

When setting out trenches (when digging out), rather than keep having to get the tape measure out, we use a length roofing batten with building size and trench size marks sprayed on it. Drop the lath against the existing building and spray marks on the ground where they tally with the marks on the batten.

It saves having to keep getting lies out and any digger lines you put on the ground get churned up once the digger gets moving around. Relevant mainly when setting out extensions.