Gazebo - Part 1 Foundation - Overview

Welcome to my second instructable, and thanks for reading! This project is all about building an awesome seating area and focus point for a back yard. The project has taken my wife and I about a year and a half to complete, working off and on. To make it easier to read, I will be breaking it up into several parts: Foundation, Pavers, Structure, Seat, and Table. I hope you learn a thing or two and laugh from my mistakes. Ultimately I'd love to help and inspire DIYers to try something like this yourself, Enjoy!

Our backyard is a mess! Well more of a blank canvas I'd like to say. Looking at what we had to work with I decided we needed a focal anchor in our backyard, a place to separate the "wild" from the "tamed" space. My solution was a raised hardscape patio with a wooden structure to separate the two spaces.

Part 1 - Foundation ~$200

We had some gorgeous white granite rock already in place as a ring around the pit. This would become the walls, anchored between 4 concrete piers, topped with a line of bricks, and structurally backfilled.

Part 2 - Pavers ~$300

I used a mix of paving stones from the Big Orange Box, and some "flag" stone I found on the side of the road. These were placed in a circular ring pattern.

Part 3 - Structure & Bench~$400

An eye pleasing barrier between the yard space and the patio space. Also the backs to the bench. Made with Redwood.

Part 4 - Table (planned for the future)

I like to work with what is available, and it didn't take much of an imagination to come up with a raised round patio. AS with every project I used google, pinterest, and of course Instructables for inspiration and how-tos. Sadly I wasn't able to come up with a blueprint for what was in my head. But I was able to pull from several different projects, my own experience, and mock-ups to finalize the idea. Further, I used a simple website to help with the Hexagon dimensions and angles.

Turns out a hexagon is awesome in that it is comprised of 6 equilateral triangles. Each "slice of the pie" is a triangle with 3 60* angles. This made the layout quite easy.

I wanted to mimic the curves in nature and one of the themes of the yard, so i decided to make the foundation circular (linking the points of the triangles/hexagon). Also a theme is natural materials. This project was made from rock, stone colored bricks, and redwood.

For the foundation we used the following materials:

Materials:

• Piers
  • 8 sacs of 80lb 500psi concrete (thinned with a little 50/50 sand gravel mix)
  • 2ea 6' sono-tubes (cardboard type tubes for forming piers)
  • 4ea 8' #3 rebar (used for "stirrups" or U-shaped rebar bends)
  • 4ea 4x4 post embeds (metal pieces that are placed into wet concrete to receive wooden posts)
  • 2x4s (bracing the sonotube, ie "kickers")
• Wall
  • Non-expansive base material (we used decomposed granite, as we had it on hand. sand/gravel will work well too)
  • Boulders (any rock over 6" in diameter. We had some around the property, and I found some elsewhere)
  • Rocks (smaller filler rocks for filling in holes)
  • Mortar (like concrete with no rocks in it)
• Brick Topper
  • Pavers/Bricks
  • Motor
• Structural Backfill
  • Non-expansive dirt (we used decomposed granite. DO NOT USE CLAY)
• Fill Material
  • Native soil (clay is fine up to between 1' or 6" from the finished grade)
  • Non-expansive dirt (again, we used decomposed granite)

Tools

• Wheelbarrow (for mixing concrete or moving materials)
• Small concrete mixer (not required but sure saves labor)
• Spade Shovel
• Square Shovel
• Something to dig holes with (we used small shovels, trench shovels, a prospectors hammer, really anything that will get the job done depending on soil type)
• Hoe (for mixing concrete)
• Trowel (for leveling and finishing concrete)
• Hard bristled brush (for cleaning mortar joints)
• Wooden stakes
• String line
• Line Level
• Level
• Hammer & Mini Sledge
• Something to compact with (manual tamper, body weight with shoes, machine compator, ect..)

This is the most critical step in my opinion. Everything is based off of proper placement and locations.

We started finding a center point that was 6' from the existing patio we wanted to "tie-into". Then placed a sturdy wooden stake (or a metal dowel would work too). Using a string line and level, we set the measurement 8" above the highest intersecting plain. (Essentially we found the highest point around the circle and measured 8" up from there, we didn;t want a set less than 8") Pulling the string tight from this high point, and moving it up and down our center stake, we found level referencing the line level, and marked the center stake. This line would determine the top elevation of the piers, walls, and FF (finished floor).

(side note, this can all be done with a theodolite and a philly rod, surveying instruments, but I don't have those so we did it the old fashioned cheap way! And the measurements can out close enough)

Next we decided the placement of the piers and ran 2' off-sets for the center of the piers. (and off-set meaning a mark or point that is a certain distance from where the actual point will be. This way you know where the center point is while working on it.

Finally we set the location for the all the piers using the great 6' radius and band measurements that the hexagon allows.

Now you want to dig about 1' below (or the deeper the better) the existing grade for your piers. In a hilly environment like ours, each pier will likely be a different total length. This is OK, just remember some piers will need more material than others.

Cut the sonotube to length. Measure from the existing ground (or if you made your hole wide, the bottom of the hole) to the finished grade (the mark on the center of your stake). Check with a string line and level before making the cut. I used my skill saw to cut the tube.

Install your bracing as you make sure the tube is level and plumb.

Hang your rebar, or support from below with a small concrete block (will be covered with concrete).

Mix your concrete and pour about 1 foot at a time, making sure to stab the concrete (from above) with a metal dowel. This will make sure you get good consolidation of aggregates (rocks) and remove air bubbles. Each lift should take 10 to 30 stabs. Pour each lift before the other starts to harden, otherwise you'll have a cold joint and this will weaken the pier.

Once poured to the top, place your 4x4 post embed in the WET concrete and finish any exposed area with a towel.

Allow to cure for at least a day, then remove the sonotube. (a total pain to do if you just forward to the next step, as I did, lol)

A few notes

• Concrete can burn your skin, please wear protection (gloves, glasses, long sleeves)
• its ok for the concrete to burdge out of the bottom of the sonotube, as long as its below existing grade and you've got the extra concrete for it!
• Placing the embed into the wet concrete can be a pain in the arse! Test fit it around the rebar before placing the concrete
• The direction of the post face will be dependant on how the embed is placed
• BUY A QUALITY EMBED! this was a mistake I made and now two of my posts wobble a bit....

Now the real craziness begins, Rough Stone Masonry!

If you have not done any type of masonry before, please practice. This was by far the most difficult and skilled thing I had done to date. Many skills are required and if using big stones, you better have a football player handy to help place them. Watch youtube videos to help learn how.

*One mistake I made was to try a single layer wall. This was extraordinarily difficult, and I felt the wall was weak. A proper stone wall has at least 2 layers, allowing the center to be filled with mortar.

Lets get started:

Layout the wall, we used our handy center stake with a 6' string line to make a mark in the ground as we traveled in a circle. This is the face of the wall. In my case this was a circle between the posts.

Dig 6" around the base of the wall. This should be slightly wider then your rocks. Add the non-expansive fill and compact. (Another nice thing about this hexagon design is that you can work on one piece of the pie at a time.)

Dry fit your 1st course of boulders thinking about the wall as a whole. Ideally you have an inch or so between all gaps. Keeping the face flat is of particular concern. Once your satisfied with the dry fit you can either remove each rock and place conc (concrete) underneath, or just leave them on the compacted earth (that's what I did and they seem fine a year later.) Dust off the rocks with your brush and begin to fill the gaps with mortar. Skill in this only comes with practice, so have at it!

Let the mortar set for about 30 min and then brush with your hard bristle brush. This will smooth out the finish. The trick is to get it while its still slightly wet, but not too late as it's dry. Finally wait for it to dry overnight and begin your structural backfill up to the point of where you stopped your mortaring.

I specify "structural" backfill because this is actually part of the structure. It has to be done correctly to help support the wall. Using a non-expansive material (sand gravel mix or similar) place in 4"-6" lifts or courses behind the wall and compact. This should be as wide as to accommodate a 30* slope from 1' from the top of the wall. Continue placing and compacting courses until you have reached the top of your mortar work.

Continue placing mortar until you are ready to place more boulders and smaller filler rocks. And don't forget to backfill!

Again, dry fit these first. Check with the string line that you are maintaining your face or arch. Then slab a bunch of mortar down and squish the rock/boulder into place.

Continue with steps above until you have reached an elevation that is your Finish Grade minus the thickness of brick you intend to use minus an inch. I strung a string line between the tops of all the piers to give me a reference as I moved up.

Once the rock work is completed, and everything is backfilled, it's time to place the brick top course! Before I did that I placed the wood posts for the gazebo, so that I could brick around them.

The simple part of this step is slapping down some mortar and pressing the brick into it. The difficult part is making sure your brick line is level and (in our case) maintains the 6' radius to the face of the brick. The rough stone masonry work you did below will also make this step more challenging then at first glance.

Brick laying instructions:

• dry fit bricks in place & get materials ready
• clean (brush) surface area where mortar will be placed
• slap on a good amount of mortar from your trowel
• scrape on mortar to one side of the brick (this is the side that will connect to the followig brick)
• push the brick into place, leaving it a bit proud
• check for level, plum, and layout. tap with the butt of your trowel for minor adjustments. tap with a rubber mallet for larger adjustments
  • check level across several bricks to be sure your staying true.
  • a string line placed just above the brick course will help your eye stay on track (this makes it so much easier)
• once satisfied move onto the next brick and continue steps above.
• after curing for 15-30 min (depending on a bunch of factors) brush off the joints for a clean look

Now that the brick top course is placed, its time to finish the backfill and infill the "dead space" under the pavers

At this point you should have a non-expansive dirt material backfilled along your wall up to the bottom of the brick top course. Then you will infill everything in side of the foundation up to 6" below the bottom of where your pavers will be. The "infill" soil can just be native soils around the yard, anything will do but try and keep organics out of it (roots, grass, ect..) Do this the same, 4"-6" lifts, compacting between each lift.

The foundation is now competed! Its time to move onto the next chapter, Part 2 - Pavers!