DIY Chimney Renovation


When we first purchased our new home, there were a few things that had to change immediately.

One: The entire house had been painted in tan. Seriously, the ENTIRE house. Both Cassandra and I much prefer our blues and greens to reds and yellows, so we needed to change that pronto.

Two: The chimney. The tan paint over wood paneling was not anything remotely resembling what I would call attractive.


The Materials:

I’ve always loved the look of stacked stone, but we weren’t sure we would ever be able to afford it. However, I stumbled across some Pinterest posts about people using a product called Airstone. Essentially it is lightweight concrete molded from real rock molds and then “painted” to look more realistic. And unlike many of the other faux-stones out there, each piece is individually made, instead of being in groups of stones. When we started the project, there were only two color variations at the time. Autumn mountain and Spring Creek. Spring Creek had the more cool tones that we were going for, so that’s what we went with. There’s a calculator on their site to determine how many boxes of normal stone (with unfinished edges) and edged (which look more like natural rock, for any exposed edges).

We also wanted to cover up the brick (since this was the only brick in the entire house) with concrete to get a more industrial look.We plan on doing the kitchen counters and bathroom counters in concrete as well. Again, on Pinterest, I had discovered a plethora of people utilizing a product called Ardex Feather Finish. There is also a version available at Home Depot called Henry FeatherFinish.

The last thing I wanted to replace was the mantel. It was rough-hewn lumber that had been painted a thick black, and just didn’t fit into our aesthetic. Since we had done our industrial furniture the previous fall, I wanted to go that route and create a faux-beam mantle that looked very old and worn.

So we ended up getting:

  • Airstone = $525
    1. (6) boxes of normal pieces(each covers 8 sq ft) = $60 each = $360
    2. (3) boxes of edges (each covers 6 linear ft of “edge”) = $40 each  (now $60) = $180
    3. (3) buckets of Airstone adhesive = $16 each = $48
  • Concrete = ~ $50
    1. (2) boxes of Henry Feather Finish = $34
    2. Various concrete trowels/tools
    3. Cleaning Rags/Mixing buckets
  • Mantlepiece = $55
    1. (3) 1″x6″x6′ white pine = $27
    2. Minwax stain (Jacobean and Red Mahogony) = $12
    3. Minwax Polycrylic = $16

The Process


The first thing I needed to do was remove the trim and mantlepiece. They were unfortunately holding on very tightly, so it was a lot of destruction work. Cathartic, I suppose… but also time-consuming. It was here we discovered what the wood paneling behind actually had looked like. I think perhaps the previous owners painting it *was* the better choice after all.


I also needed to re-route the switch to our fireplace fan into the area for the mantel. I also ended up spray painting around the areas the mantel was going to be near and around the fireplace opening, since I could not entirely cover up the paneling in those locations. It helped to hide it behind.



As soon as that was done, I needed to have the finished footing before started slapping stone up on the wall, I began with the feather finish overlay on the brick.

You have to mix the FeatherFinish in a small bucket with water. It may seem like it’s a pain to do it in such small increments, but honestly, the stuff dries so quickly, that I had a hard time getting it all down before it started to get too thick to work with. I ended up mixing it a little thinner in subsequent mixes.

Each coat required about 2 small buckets of skim coat to complete. It definitely needed both coats to make sure all of the impressions from the brick beneath it did not show through.


Next to tackle was building the mantle. I cut one of the 1×6’s with all edges at 45°, and the other two leaving one of the long edges still at 90°. I then had to cut the end caps to match. each with 3 edges at 45°.

I was in a hurry, and things didn’t line up correctly the first few times, so I will take the time to reaffirm the old adage, “measure twice (or 3 times), cut once”.

Once the pieces were cut and fit together, I used my trusty Kregg jig to screw it together and glue it.

Similar to our industrial furniture, I really wanted it to look like it had been well-worn. So, I beat the tar out of it with various things, gouged it, took some big chunks out of it with the hammer claw, and then spend several hours sanding it all down to a smooth finish.

With stain, I always like to do a dark layer of Minwax Jacobean to seep into all the imperfections and gouges and stuff, and then finish it off with Minwax Red Mahogany. Then 2-3 layers of Minwax Polycrlyic, with some careful sanding in between with 220 grit sand paper sponges. The last layer I used 320 grit and then some steel wool to get a super glassy smooth finish.

Brick By Brick

Once the concrete was dry, I felt good about starting with the Airstone. I opened up a package and tried to organize it and set some rows out to get an idea of how it would piece together.

The first few bricks were easy. Slop some adhesive on the back (as the bucket instructions say, like icing a cake, not like buttering toast) and stick it to the wall.

What I did not anticipate was that the distance between the edge of the chimney and the edge of the fireplace was not a nice even number. So I had to cut at least one piece of Airstone per row, per side.  There are chop saw blades that cut through these like butter, which I would recommend, but, as I was not able to borrow my work’s saw for this particular project, I was left to other devices.

So I used a hacksaw. As you can guess, it took awhile. But it was all worth it.

A month of painstakingly cutting and gluing AirStone compressed into a few seconds.

I ran into a few other obstacles along the way. The adhesive doesn’t hold much weight when it’s wet. The stones tended to sag unless they had something beneath them. So the point where I needed to bridge over the fireplace area, I had to do some ghetto rigging to keep it up until the glue dried enough to hold. This is also where I realized how not-level my floor was. I ended up having to deal with slightly unlevel stones to make lines that “looked” level, and I added little gaps between rows with shards that had broken off of some of the stones.

Once I got up to the point where the mantel would go in, I had to do some measuring and figure a few things out. I needed to attach the claw onto the wall so that the mantel would slide down on it and sit perfectly. I had to make several tries with this to get it to sit nicely (and level), but I finally got the mantle attached.

The wall side of the “Claw” to attach the mantle

The next problem then asserted itself. The stones are 2 inches high each. I had started with a 1×6, so I thought to myself “Self, that should work out just fine. The mantle will fit perfectly between 3 rows of stone”. Only I didn’t think about the fact that that actually means 3/4″x5 1/2″. And, with the 45° cuts, I had taken off a hair more as well. So that left a little more than a 1/2″ gap between the top of the mantle and the top of the stones next to it. Since I was using a hacksaw, I didn’t feel like I could cut my Airstone down to a 1/2″ sliver.

Insert clever idea: I had concrete skim coat…. why not get some square wooden dowels and coat them with concrete?


The mantle in place

From that point, the process went a lot more quickly. Fewer cuts, since I was working across the whole width. And I had become used to the pattern of trying to make sure and spread the darker stones out. As you can see in the finished photo, I had to use the wooden dowel trick again on the top layer, since there was 1/2″ to 3/4″ gap between the top row and the ceiling. These I ended up mixing a little thicker, since they ended up darker, but it looks like an intentional capstone… so I didn’t argue.


Overall, even though I had some extreme frustration a couple of times during this project, and there are glaring imperfections there if you know where to look, Cassandra and I LOVE how it turned out. It changed the whole feel of the living room to something classy but somewhat modern. The new mantel matches our industrial furniture, and unless you see the before pictures, it looks like real stone.

Things I learned on this project

  1. How to pull of trim and a mantle. Wanton destruction.
  2. How to skim coat a surface with concrete
  3. How to (sort of) build a brick wall
  4. How to rewire an electrical switch
  5. How to make a faux beam out of 1x6s.
  6. Airstone are really hard to cut with a hacksaw. You can do it, but it takes forever
  7. The glue smells like butter cream icing. No joke. I wanted to taste it several times.
  8. This was the ultimate jigsaw puzzle
  9. A bubble level is your best friend, and also your worst enemy, especially when it reveals how “not” level your floor is.
  10. Always over-estimate the time it will take to do a DIY home project

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