I’m hoping someone can share some technique with me to make screeding for a bluestone patio a bit easier. In the past I’ve buried a length of lumber within the stone dust on top of some stakes driven into the compacted stone dust. I bury a similar length about 4′ or so parallel to that. I leave the top of the piece of lumber at the finished level height of the stone dust and screed that by moving a 2 X 4 across the lengths. I then lay stone over that base.
Problem is that this seems a bit too time-consuming. After having leveled off the area I end up having to remove the lumber and fill the void left by that lumber before laying the bluestone. This disturbs the base somewhat and takes time to repair. Laying the initial lumber out to a level height (taking pitch into consideration of course) also takes more time than I think it should.
Does anyone have an easier method to laying out the lengths of lumber, pipe, or other material to the finished height which would also facilitate screeding and removal of the screeding lengths? What materials do you use to establish the screeding surface?
Thanks for any replies.
Replies
Joe,
I think I understand what you are trying to do but I'm not sure why you would want to do it. I set up stakes on the corners of the patio and run string marking the finished height of the stones. As I bring the base (stone dust) up, compacting it in lifts of only a couple of inches, I stop 1.5 to 2 in. short of the string, depending on the thickness of the stone I'm using. I use the transit to make sure I'm in the ball park all around the base, but I don't worry about getting it perfect.
It seems to me that with the inconsistency of the stone, fussing with a perfectly level base is a waste of time. Every stone is going to need to be messed with to get it to sit level which may mean taking some dust away here and adding some there. If I add more than a half inch or so, I hit it with the hand tamp.
The string gives me an elevation and guide to follow for straight edges and square corners.
Am I missing something?
Brian P.
It's my job!
Thanks Brian.
I think your reply, "It seems to me that with the inconsistency of the stone, fussing with a perfectly level base is a waste of time " says it all. Maybe screeding it is a waste of time due to different heights anyway.
Do you run string across the width and lengths of the patio every 2, 3, or 4 ft so you can get the finished height fairly uniform? Like an interesecting grid of level string or is that too much as well?
I've also seen recommendations to set the bluestone in a mixture of 1/12th portland cement and 11 parts stone dust. I guess this is just enough to hold it more firmly in place than just stone dust alone. Does this offer any advantages.
Thanks again.
With stone, it is definitely a waste of time to screed the base.
For pavers which are uniform in thickness, we use 1/2 inch galvanized pipe in 10' lengths. We shoot each end of the pipe with a transit to establish pitch. Then screed with a 2x4. Pull the pipes, tamp one more time, put the pipes back down, and screed sand as a setting bed. No stakes, no embedded lumber.Bear
I just string the perimeter and try to work off of the string as much as possible. Of course I check each stone for level and also level from stone to stone. In fact I use the level a lot while laying flagstone. Bearmon is right on with the pavers. If you can get a level base with pavers it is as easy as placing them down.
Brian P.
It's my job!
Thanks for the help Brian and Bearmon. Should go a little smoother now with your advice.
Joe I have laid 1000's of sq.ft. pavers and stone. The easiest way to do this type of job is as prev. mention. I will add a few tricks.
1. excavate and compact 4-6" grandular base
2. use steel pipes 3/4" as opposed to conduit they will not flex when screeding,lay in base approx. every 2' apart
3.take thickest stone and set sub-grade to this height,less 1" (ie:1" stone, set sub grade 2" below finish grade)
4.remove pipes after screeding fill little trenches with granular base, pack with mag float and trowel level
5.add 1" pea stone to area, this will allow you to worm stones into place thinner stones add a little more pea, use level to check with corresponding stones
6. mix mortar in with sand to sweep over finished walk/patio, this is not a wet mix mortar is only to give sand a little binder, atomize with water after joints are filled and patio is sweep clean
7. work off material as you lay it, to not distrube base
8.you will need approx. 2-3 % slope for patio to drain prop.
9.use this formula to set grade G=V/H G=% of slope V= vertical height H= horiz. distance
hope this helps good luck
By 1/2 inch galvanized, I meant waterline, not conduit. 1/2" works fine. I don't see the need for 3/4.Bear
Don't you find the sand and mortar mix cracking and coming out in chunks? I'm in the NE and I know that would happen here. The last guy I worked for had me pack the joints with dust. But not with a broom. He had me work dust in with a trowel until the joints could take no more dust. His work seemed to hold up great. We had a lot of regular clients who had 10-15 y.o. flagstone patios that showed little movement.
Cheers,
Brian P.It's my job!
The amount of mortar to sand is minimal, don't really remember the mix it was one of those things that you develop. If one was to look you really wouldn't know their was mortar in the sand. If memory serves me it was 1 scoop to a wheelbarrow of sand. It basically kept sand from being real loose when it dried completely. If one was using crusher dust than mortar probably wouldn't even be necessary. I really didn't make that real clear in post, if it appear that I was proposing a mortar joint I stand corrected.