Proper capping of semicircle step on paver patio

[Chance]

Hi, this is my first post here. I've been lurking for several months, and have learned far more by reading these forums than all the other web resources I've consulted, combined.

I'm in the process of building a 350 sq. ft. paver patio extending from the back side of my house, surrounded by a 2' Allan Block courtyard wall. I'm also using some of the Allan Block York units to build the step up from the patio into the house. I've completed my demolition of a much smaller concrete pad, excavated, and installed around 6" of compacted 3/4 minus crushed granite. I'm still tweaking the grade exactly the way I want it, but I'm about ready to start doing the wall and step, and then the pavers.

The step will be a half-circle, with a 40" radius. The back side of the step will have to come up into the first level of siding, so I'll be cutting that off and installing some flashing for the step to rest against. I have two questions:

1) Should I also put a line of block along the back of the step, against the wall, so that the entire outside perimeter of the step is outlined in block, or is it okay to just have the circular portion blocked and do my compacted gravel infill right against the foundation/flashing?

2) Ideally, I would like to have the actual cap of the step made of a single, half-circle chunk of granite or sandstone. I'm fairly certain I can't manhandle a stone of that size myself or even with the wife's assistance (I'm guessing it would weigh a few hundred pounds?), and I'm not sure a pro mason would even want to screw around with what would be to them such a small job. Although, if there are any pros from the Denver area that are interested, I'd be happy to hear from you. My backup plan is to use pavers for the cap. I know I would need to adhere the soldier course to the supporting block, but the internal pavers would be resting on the sand bed that is in turn resting on the compacted gravel. If there was even a slight bit of settling of the sand/gravel, a depression would develop in the center area of the step. Is there a technique or something else that needs to be done to ensure the step cap stays stable?

Any advice would be greatly appreciated!

[Stonehenge]

Hello Chance -

Unless you intend to pour a slab as the base for the riser for that step, I'd reconsider the single granite slab as a tread idea. By nature the pavers you're installing are considered a "flexible" pavement, meaning they can and will move during freeze/thaw, but can absorb those movements and still be functional (asphalt is also a flexible pavement, fyi). The same is true for a segmental retaining wall. Which means that if you place a large (and expensive) slab atop something that can and will move a bit here and there, and possibly settle near the house (which is much more likely if being installed by a novice), you'll end up with a broken piece of granite and a broken spirit.

So for the time being let's assume you'll use pavers as your tread.

Several years ago we used to install steps similar to the way you're considering...we've since stopped installing them that way. There's too much of a chance of having just a tiny bit of settling beneath the pavers that are right next to the block, and the tiny bit of settling will quickly change the look and function of your steps.

The preferable method is to construct a riser made totally of block - block at the perimeter and block within the perimeter. Then use pavers as your tread (and your only tread - no wall block caps). Then the whole works is sitting on a single prep job and is just about eliminating the chance of any settling. And frankly, the look of an all-paver tread is a cleaner, better look to me.

In the pic below you can see what I'm talking about, though it's not the exact same situation - we were in the process of building steps from a lower patio level to an upper.

[Chance]

Thanks for replying. The more I've been envisioning the patio in my mind this afternoon, the more I've been thinking that the monolithic stone look just wouldn't fit with the rest of the patio, so I was starting to like the idea of matching the pavers I'm using on the patio surface itself.

Great picture, that looks exactly like what I should do. Do you fill the voids in and between the blocks? It sort of looks like the guy to the left is doing that, but the view is blocked. If so, do you infill with base material, or sand? Finally, do you then glue all pavers to whatever block surface is available under them, or just glue the edges and let the inner ones rest on top of the block and infill material?

[Stonehenge]

More often we use solid block like Versa-Lok, so filling voids is less of an issue. For this project we filled the voids with 3/4"-. But for solid block I prefer to use cut pieces in the gaps between block.

[Bill Schwab]

We have taken retaining wall blocks and made a stair, then poured a cap in the same color as the block. You can use a styrofoamslip form to bull nose it, or you can form it up, peel off the forms them take a masons hammer and ding up the face to make it look weathered.

I do not know if they are available in Denver, but let me make this suggestion. If you can get a hold of Unilock gardenstone, they will make a perfect 36" radius without cutting. You set the bottom elevation and step hieght then model the rest from that.

No muss no fuss! I know ideally you are looking for a 40" radius, so to get that just take one straight sided block and cut it to 4" and set that right in the center.

What I have found with other products (Pisa 2, Alan block, Keystone etc.) is that tight radius's such as you are looking to make are difficult to get the caps all to look right. With the pre engineered blocks it takes the guess work out of the equation.

[Chance]

I think I can get Unilock products around here somewhere, I'll look into that. There are a couple reasons I was using the Allan Block York units. The main reason was that the courtyard wall I'm building is the same type of block, so the step face would match the courtyard wall perfectly. Also, this step is going to be recessed back into a rectangular sheltered area where the door slides open. By happy coincidence, the York units have a natural 40" radius, which fits perfectly into the recessed area with a couple inches to spare on each side at the back where it is widest.

If I did decide to use wall caps as the outer edge of the cap, I believe they would work perfectly with that radius, with no cutting. I'll have to yank a few off of the pallet, but I'm pretty sure they were designed with the Yorks in mind. I don't really like the look of these particular caps as treads, though, so if I stick with the Allan Block I'll come up with something different.

All in all, I've now got lots of information to ponder with regards to my step. Thanks guys!