View Full Version : Installing a flagstone sidewalk

Brian Hale
05-29-2005, 8:34 PM
SWMBO is laying out a sidewalk using some old flagstone from the original house. It'll be about 40 long and vary from 4' to 3' wide. She wants concrete under the stone so the grass won't be a problem later on.

Any ideas how best to approach this? We're thinking of pouring about 3" concrete and setting the stones on it while it's still wet, but the stones vary between 1 1/2" and 3" thick. Also, whats the best way to fill the gaps between the stones?

Brian :)

Ernie Nyvall
05-29-2005, 10:05 PM
You can do it that way with the concrete, but if the sidewalk is too long without expansion joints, it will crack and you will get grass anyway. Make sure you put steel in your concrete to help stop from cracking. For the joints you can sweep dry mortar in the joints and sprinkle with water.

Another way you can do it is to dig the walkway as you would for the concrete. Put heavy plastic down and fill on top with sand. Put your flagstone down and tap it even making sure you fill all the voids underneath. Then do the mortar.


Jim Becker
05-30-2005, 10:37 AM
LOL! Guess what I've been doing this weekend...yup, laying a flagstone walkway in a mortar bed. (I'll be posting a separate thread later with pics) Take the top soil out of the area, put in a layer of stone (I used 3/4" crushed since I had it left over from the driveway) leaving about the thickness of the stone plus about 2" for the mortar, tamp it down solid and put in string lines to measure from...and start mixing your mortar; relatively stiff. Only put down at once what you can reach over to lay the stone. As you place each stone, wiggle it just a little to get a 'Grip' and have a rubber mallet handy to whack it into submisison and level with the intended surface position. The work goes fast...the only time consuming part is mixing the mortar once your area is prepared. (Having a second strong person to deal with that could be helpful)

For the gaps, you can get what looks like a pastry bag at the 'borg to help you grout the gaps with mortar after everthing else cures for a few days.

Jack Wood
05-30-2005, 11:05 AM
Hey Brian, well take it from someone who could write "how not to books" that the sweeping the mortar in and wetting it down won't work. I listened to several people who said that I could just dig out the walk and lay down crushed stone, compact it, lay the rocks down, then sweep in a sand and mortar mix to fill the joints. Well I did all that and by the next fall the mortar was popping out and crumbling. You will never get all of the mortar/sand wet enough to cure so you will have it not adhering to the stones and because of movement of the stones, yes you are going to have some cracks, breaking apart. I had to tear the whole thing out and start over. This time I read on the web about the correct way to do this. Dig out your path and place an inch or so of crushed stone down and compact it. Then you either need to rent or buy a mixer. I bought mine at Lowes for around 250. You will never be able to mix up in a wheel barrel the amount of mortar needed. Pour a 2-3 inch pad of a mortar mix, get the type with the sand already in it. Squish your rock down into the mud, at this point you have to make a decision. Professionals would leave a joint all the way round the rock and then come back and grout in all of the cracks after the mortar base had set up. If you have a large walk this could really take some time and patience. The other alternative while a little messier also works. Take the rocks and butt them up to each other so that the mortar comes up between them. Scrape off the excess and before it sets up hard smooth out the joint and get it off the rock. The sell a mortar release agent to help in this but I didn't use it. I worked 3-foot sections at a time and had my wife and son helping. 2 years later there are a few cracks, but your going to get those if there’s any slope to the walk no matter who does the job. Here’s a few pics of the walks, I thought I had better ones but guess I never took any. GOOD LUCK!

Jim Becker
05-30-2005, 11:10 AM
You will never be able to mix up in a wheel barrel the amount of mortar needed.

Well...you "can", as I proved this weekend with (14) 60-pound bags...but it was not fun. I would definitely get a mixer if I did this kind of work again. No question. It's not that mixing it by the wheel barrow is hard...it's just tedious and time consuming.

Very nice walkways, there, Jack!

Jack Wood
05-30-2005, 11:18 AM
Hi Jim! If I recall right I used over a 100 60lb bags to do this job, front and back:eek: Even using a mixer I made the "Alleve" company's stock go up:D The back walk was done with a wheelbarrow and that convinced me that the front 40' of walk was either going to kill me or never get done if I did it that way:rolleyes:

Brian Hale
05-30-2005, 12:28 PM
Lots of good information guys, Thanks!!

Here's a couple shots to show what she's up to.

We've talked about the mixer and i'm sure we'll go that route as i don't enjoy mixing in a wheelbarrow. The path is closer to 30'. I like the "pastry bag" idea Jim! :cool:

BTW, this walkway and the deck in the background is all her project. I'm allowed to supply muscle as needed :rolleyes:

Brian :)

Jim Becker
05-30-2005, 12:40 PM
Brian, that's going to be a beautiful walkway. You really do have to get all that vegitation out as well as all the loose soil. The key to a successful walkway/patio project is site preparation. It's the hardest part of the work, but it has significant impact on both the initial look as well as how well it lasts over time.

Ernie Nyvall
05-30-2005, 3:24 PM
Brian, I concede to the crushed rock and premixed mortar or grout for the joints idea. The stone that I have laid before on several occasions was anywhere from 3 to 10 inches thick and nowhere near flat on the bottom all in the same batch. It took a thick layer of sand. I never had the problem with the mortar popping out as Jack wrote of, but I can see where it could do that if not completely saturated and it takes a while to get there. I forgot to mention too that I added portland to the mortar mix which helps it adhere to the rock. After seeing the pictures, I'll add to the importance of getting all the vegetation out and that top layer of soil with the roots in it.

That's going to be a beautiful walkway.

That's some job Jack did. A heck of a project and it looks great.


Jack Wood
05-30-2005, 3:56 PM
Thanks Ernie! Yeah the problem I ran into was that my yard slopes, so as I tried to wet the upper sections the runoff would washout the sections below. So it made getting a consistent "wet" impossible, so I believe thats where I had the problem. So many people told me about this way that it has to work in most cases, but apparently not on a grade.:(

Jerry Olexa
05-31-2005, 10:51 AM
Brian, looking good. Lots of angles in it as well as the landsape timbers. great results!