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Posted: Tue May 29, 2012 3:10 pm
by Paul Miller
When doing phase 1 of my project I was just about able to screed edge to edge with a single board without the need for screed rails.
However, for phase 2, I will need to use rails. I will probably use either timber or conduit for the purpose as suggested in the website, but my main concern is how to have these sufficiently fixed so they do not move or sink during the screeding process.
Thanks as always for your help.
Paul
Posted: Tue May 29, 2012 4:23 pm
by lutonlagerlout
well as you are screeding perpendicular to them and they are bedded in sand the movement is minimal if at all
I dont fix and have never needed to fix them
LLL
Posted: Tue May 29, 2012 4:43 pm
by Paul Miller
Would I just tap them down into the partially compacted sand to the required level. Or would I need to scoop out a shallow (narrow) trench for them to sit in ?
Cheers
Posted: Tue May 29, 2012 5:35 pm
by Carberry
Just dont put as little downward force on them as possible when screeding and you'll be fine
Posted: Tue May 29, 2012 5:45 pm
by oioisonnyboy
Everyone has their own way of setting up screed rails, my personal preference is;
1) spread bedding sand approx 60mm deep
2) compact with plate compactor till sand is firm, footprints do not show, minimum 8 passes
3) decide which direction you will be screeding, rails need to go in roughly perpendicular.
4) scratch out a shallow channel in the compacted sand with a shovel for each rail, place rails in scratch
5) stretch a string line or straight edge across the area to be paved to follow finished levels. Place a block on top of the screed rail and adjust rail so that approx 8-10mm of block can be seen above the string line (finished level)
6) repeat this process at both ends of each rail and once in the middle, go easy on hammering the screed rails as they bend easy. If difficult to level up, take the rail out and remove some more sand. Check the rails are not bowed using small straightedge. This will ensure paving does not dip or bulge.
7) screed sand and carefully remove the rails. As you are laying the paving you can put small quantity of sand in rail marks and smooth off with a plastic float, smooth over carefully.
The compacted sand should support the weight of the screed rail and the straight edge used for screeding, you dont need to bear down on it with your whole bodyweight, just a case of screeding a small section until it is dead right, drag any excess sand away carefully, and keep screeding.
Better to take time on this and get it spot on right, as any dodgy screeding WILL show up in your paving.