Last week we filled you in on a little project we decided to undertake involving the repointing of the interior exposed brick on one of our chimneys. The mortar of the chimney has long since seen its best days, leaving much of the old limestone and sand mortar crumbling and at a point of deterioration.

Last week's post covered the painstaking task (ok, it's wasn't that hard) of lime based mortar selection, but that was only the first step of many in a task I have long dreaded. Though the materials selection was arduous, the real work on the project was clearly the actual repointing of our brick.

The section of brick we are dealing with is along one of our three interior chimneys. Our ultimate goal is to eventually make the fireplace below this chimney a functional fireplace, though it is currently used for our furnace and water heater vent. The area I'm repointing will be covered in the future, so now seems like the best possible time to resolve the issues we have with mortar failure as a result of leak issues that were corrected long ago. The next step, sometime down the road, will be to re-line the chimney after replacing the water heater and furnace. Hey, it's a multi-year plan and this is step one of...well, a lot.

Before we started on our repointing project I gathered up all of my tools and supplies. There are more or less three categories of tools for this project, the set for chiseling the old mortar, the set for mixing the mortar, and the set for applying the new mortar.

The first set for chiseling the existing and failed mortar consists of a brick hammer (or mason's hammer) and plugging chisel. These are pretty basic masonry tools, and are always good to have on hand. I didn't own a plugging chisel so I picked up this new three chisel set for this particular project. This holds true to my mantra of "buy one new tool for every project." Just look at how new and clean they were. I also grabbed my respirator and safety glasses to protect me from any flying debris, and my work gloves.

The set for mixing the mortar is simple, and similar to just about any dry mix project. I grabbed a small bucket for the mix, another bucket for water, a mixing attachment for the drill, and my awesome new hammer drill for mixing.

The supplies for the actual mortar application are a little less regularly used, so I needed to dig them out of my masonry/grout/drywalling container in the basement. The list consists of a large trowel, brick jointer, mixing trowel, a good pair of gloves, a water spray bottle, and my chisels.

If you're a repointing veteran you probably notice a tool that is missing from my list and photo. I'm talking about a tuck pointing trowel. I made a rookie mistake on my first bit of work and didn't have this critical tool. Remember, I'm a true beginner at this, and I thought the jointer was essentially the same thing, so I started working on the project without the tuck pointing trowel. I saw the error in my ways, but I'll fill you in on that later.

I started the whole project by working to clear out the joints of the failed or crumbling mortar. Near the top of the section, where the water infiltration had been more severe in the past, the failure was clearly the worst. The previously hard face of the mortar had all but vanished, leaving crumbling sand that could simply be swept away with a scrape of the chisel. You can see the sand falling as I swiped it the tool along the joint in this photo.

As I slowly worked my way down into the more sturdy mortar the job became more labor intensive. Using my chisel and brick hammer, I slowly worked to chip away the old mortar, a little at a time, loosening sections as I went. I was very careful not to really hit too hard or aggressively, especially on the vertical head joints, otherwise I'd risk severely damaging the face of the surrounding bricks. 

It was a slow go at first, but after a little effort, I started to get the hang of it. I worked through the head joints first, then the bed joints, running course by course until I was thoroughly sick of chiseling. It's also worth noting that I made a seriously good move in buying a chisel set that included rubber hand guards. I think I hit the rubber guard with the hammer as often as the metal chisel top, especially in tight spaces. This guard saved me from tremendous hand bruising, I'm site.

Some of the head joints were so bad that you could see clear through to the interior of the chimney and the clay tile that sits behind it. This is the main reason I wanted to clean up this mortar. Even though the chimney might have a liner, I still just don't like the idea of open head joints.

Rather than clear the joints for the whole thing at once, I wanted to clear some, then try my hand at replacing some of the mortar, just to see how that part went. It also felt like I was taking on bite sized tasks, rather than tackling the whole thing. After about 45 minutes of working with the chisel I had myself enough open mortar joints that I decided to give fresh mortar a try.

You can see from the photo, these joints are wide and inconsistent. It's obvious this is an interior section of brick that nobody would ever had expected to see the light of day. Often, masons would put their apprentices on interior duty, where they could hone their skill on the way to becoming a master. Lucky for me, this meant I could be more careless on my learning project, without worry about how it would ultimately look.

The next step to the project is quite critical to a successful repoint job. Using the spray bottle I sprayed the bricks and mortar where I was planning to repointing with copious amounts of water.

I'm not saying to turn a hose on the wall, but the point of this is to wet the brick and surrounding mortar sufficiently so it doesn't suck the water from the new mortar too quickly. Brick and mortar are thirsty creatures, and if you put wet mortar on dry bricks and mortar, it will prematurely steal the moisture from the mix, causing the new mortar to cure too quickly, ultimately causing cracks and failure.

I went over the whole wall several times, spraying the area I was planning to repoint until the water was no longer being quickly absorbed. The key here is balance. You don't want standing water, but you want quenched brick and mortar.

Next I began the mortar mixing and prep process. I followed the mixing guide from the website where I purchased the mortar. 

The goal of the mix is to add only enough water to make the final product clump-able in your hand but not sloppy or soupy. I tend to intentionally over wet the mixture to allow for easier mixing, then I top off the mix with a little extra material and give a final mix with the drill. This works really well for me and is just my preferred method.

Once I was happy with my mix I started to throw the mortar into the cleared out joints. Now, I say "throw," but in reality it was more of a "sloppily place and then drop on the floor over and over." I'm not kidding you, it was a slow process that ended up with more mortar on the floor than on the wall for the first little while. I had to come up with my own rhythm and process that worked well for me. I'd place some mortar in a lump on my trowel, rest the trowel up near the joint, then use the jointer to push some of the mortar into the joint. After a little while it wasn't too difficult, especially once I got beyond the initial frustration I encountered. After about 20 minutes working, I was able to refine my skills enough to feel at least somewhat effective in repointing, but it was rough at best.

This is where I started to realize just how much I needed a pointing trowel, not just a jointer. I wasn't doing a terrible job, but the joints were sloppy, I was getting mortar where I didn't want it, and the jointer was too wide to fit nicely in the smaller joints. I did what I could with what I had and finished up the first batch I had mixed. Rather than continue on the project any further, I felt like I needed to improve my tools for the job. After all, there's really no sense in continuing on a project if the tools you have simply wont cut it.

The end result of my first day of repointing was not too shabby. Granted, I had to deal with a learning curve, the process was a bit of an exercise in futility (at first), and overall the final look was much sloppier than I wanted, but it was the first step in my learning process. The chipped and irregular brick caused some issues, as did the various sized joints and lack of pointing trowel, but I feel like I'm on my way.

After I cleaned up the work area after the first day, I headed over to Amazon to order myself proper tools for the next phase. (Oh how I love you, Amazon Prime, and your speedy shipping!) Since I'm doing this more or less real time, I'll let you all know how the next phase of the repointing goes. I have high hopes that this next step will include cleaner joints, less dropped mortar, and more adventurous repairs. We've even got a hole we'll need to patch where an old wood stove was once attached to this chimney, and a poorly patched area just below that area.

I'm going to say I'm approaching this next step with nervous anticipation more than anything else. Well, at least I'm anticipating a lot of nervousness when doing the patch. I want to make sure I can get the hang of this repointing and patching thing for when we do the exposed brick in the back bedroom. I need to have my skills refined so that we end up with good looking mortar joints. Now how long does it take an apprentice to become a master? Isn't it about 16 hours or so?

Thus far I'd rate this level of DIY as a 5 on the scale of 1-10. It's not particularly difficult from a skills perspective, but it definitely requires some getting used to, patience, and a bit of careful tool manipulation to be sure you're cleaning and filling the joints sufficiently.

Be sure to check out our followup on our repointing efforts. After this rough start to the process we were able to end with ultimate success after finding the right tools and technique.

Comments 5


4/9/2013 at 1:27 AM
I think it's looking pretty good so far. Where you'll be doing patches that will show, it seems to me that I've seen brick layers use some wide scruffy brushes to lightly clean off any stray crumbs or raw edges.

I found a video with a fairly good technique (although I'm pretty sure you looked up several as well). This guy makes it look so easy... but you can see the light brush work at the end. His joints slope down, but that depends on the style/application, etc.
JC, the brush was also definitely missing from my tools. I've added it for the next batch and hope to have better results.

I did see some videos, but hadn't seen that one. Very helpful, thanks. I hope to show of my improved skills in our next repointing post. Fingers crossed.
4/9/2013 at 9:44 AM
Alex - Your work looks more than fine for your first go. I am a project manager for a masonry restoration company, most of our masons like to use a tuck pointing trowel for this work. Marshalltown makes a variety of these tools which are basically a trowel with a narrow rectangular blade which come in various widths to match your mortar joint. The technique is to use another trowel such as a concrete trowel or triangular trowel held upside down as a hawk to hold the mortar. This is loaded with a quantity of mortar and held up to the bottom of the mortar joint and the tuck pointing trowel is used to shovel the mortar into the joint. This technique gives you great control and reduces the amount of mortar that gets smeared on the face of the brick. If you are really particular you could mask off the brick with tape to prevent that.
Thanks, Larry! You'll have to give me your opinion on our next repointing post in a few days. The technique you described is essentially what I've ended up doing. It works well everywhere except up near the ceiling, where I really can't get a good angle. The tuck pointing trowel is definitely going to make the process much smoother. I've got two sizes on the way, a 1/4" and 1/2" since the joints vary so much. Then I'm just using the trowel I have as a hawk up next to the brick and joint, as you've said. The final thing I've added is a good brush to smooth it all and brush away excess after I've applied the mortar and it's set up just a bit.
9/2/2013 at 12:09 PM
Looks good Alex.
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