Levels

[mo-uk]

Hi
Just looking for some help understanding levels.
I've made some images to assist.
You have to click the link as cannot embed them.

Picture 1

https://ibb.co/PzsC8gm

As I understand it
-you choose where you want the patio to go up to on the house (150mm below DPC)
-rather than relying on the brick line you put two pins (or similar) at each end and then run a string line across
-you then use a spirit level to check level and adjust heights at pins until level

My query here is what happens if the string moves because of the weight of the level?

A way around this appears to be to put something like bricks EXACTLY underneath the string at intervals and then check the level that way


Picture 2
https://ibb.co/WBJrkQ7
What if your house is at an angle but you want the patio not to follow the angle of the house
In my case it would look silly as I have flats opposite so I want the slabs to be facing a certain direction as in the picture below

I cannot think of an easy way around this other than to do it by eye....

Picture 3


https://ibb.co/dKCjq93
In relation to the falls, I understand you put pins and a string line at the house and at the end of the patio and get it level as before. You then calculate the fall. Would you then just mark the pin by that amount and lower the string - and that is your finished level.

You could then run a string line going the other way (if it helps). For example, in my case I want ACO drainage so it would help to have a line running across the end level of the patio

Picture 4

https://ibb.co/3yQbd6r
This is basically where the string lines cross each other when working out the fall - is this the best way to do it or is it better to have a pin in the middle where the strings meet.
Not sure how it could keep the same level across the T junction though.

[Tony McC]

While a string line against the brickwork may be useful for some, it wil inevitably get in the way of the laying process. Most professional installers will rely on following the brickwork AND using a long straightedge to assess the level of the paving against a fixed point, which might be a line pin or a brick or similar.

"Supporting" a string line with bricks is a bit of a nonsense. Use a straightedge!


Laying at an angle - establish a taut string line that is aligned to the angle you wish to lay at. If you want the paving to be laid at, say, 30° to the house, set up two line pins at that angle and connect via a taut string line or straight length of timber. Use this as a guide for an establishing course and then,m as laying progresses, make back-check measure menets to ensure the flags are not drifting. Or us additional angle-set lines.


Establishing Falls - a whole page given over to this subject - https://www.pavingexpert.com/setout02


Where string level lines cross, it's always best practice to have an intercept pin to keep BOTH lines at the correct level.

[mo-uk]

Where and intercept pin is used how do you ensure both liens are level - presumably one must be under the other - or is this not considered material

also any suggestions on how to wrap it on the pin

[Tony McC]

If there is any difference in the string lines on an intercept pin, then it's the thickness of the string, say 1-2mm.

Tying lines to pins is covered on the pages I referenced earlier.