If you have an older brick house, you likely have some areas where the mortar between the bricks needs some attention. If you have a LOT of areas needing help, you probably should hire a professional who can “repoint” or “tuck point” the brick. That is a tedious, time-consuming and costly task. It’s often performed from a scaffold, ladders, or a lift, so in addition to the skills needed, there is an element of danger. Professionals will likely use a grinder to actually remove some of the old mortar before replacing it with new.
If you’re a do-it-yourselfer and just need a few areas done, you likely won’t hire the job out. That’s the focus of this month’s article.
First of all, you need to understand just a bit about the various types of mortar. For our purposes, I’ll be talking about type N and type O. The difference between them is largely the ratios of the 3 main components, Portland cement, hydrated lime, and sand. Type N is very strong. In fact, it’s stronger than the bricks used for most older homes. You should NOT use type N for older brick repairs, because should there be a situation like a water entry and a freeze/thaw, it’s likely that the brick will be damaged rather than the mortar. It’s obviously easier to repair and replace mortar than it is to replace bricks, so you really want the mortar to be weaker than the bricks. Type N is available off the shelf in most any home supply store, and is fine for modern, strong bricks. In all my years, though, I have never seen Type O available anywhere. What’s the solution? Make your own. The components mentioned above ARE available most anywhere. To get a typical type O mortar, mix 1 part of Portland cement, 2 parts of hydrated lime, and 8 to 9 parts of fine sand. Easy-peasy. Here’s what my mix looks like:
Mortared joints come in various styles. Some are neatly recessed and tooled, some are basically flush with the bricks, and some look like the mortar has actually been squeezed out. Depending on what your situation is, you might need different tools than what I used on this project. Here is what I needed -- a small triangular trowel for mixing, a larger trowel with a long straight edge, and a very small trowel to pack the mortar in:
If your joints are recessed and shaped, you will need something like a wooden dowel (in a pinch) or the actual tool made for this, which usually has 2 different-sized ends to match several joint widths.
Here is a small joint defect that can use some attention. There are plenty of larger ones on this job and over time I hope to address most of them. Note that on this particular house, the mortar is essentially flush with the bricks, but also has a red brick color to it:
Mixing the mortar in an auto supply store oilpan worked well for me. It doesn’t take much water to go from being too dry to being too wet, so add water little by little, mixing as you go. The mixture should be moldable in your hand without water squeezing out. In 5 minutes or so of using your mixture, you’ll know whether it is too wet or too dry.
I added concrete colorant, which you likely would not need to do, to help the mixture match what existed on the house. As always, I have no intent to promote a particular brand of product, but simply show you what I used:
For application, I used the triangular trowel to place a clump of the mix onto the larger trowel. Holding the larger trowel against the lower edge of a mortar joint, I used the small trowel to force the mortar into the space where it was needed. I believe the overall success of using this method depends on getting the mixture packed well, and the small trowel makes that job easy. Of course, the secondary goal is to keep as much of the mixture off of the faces of the bricks. I took this picture from high on a scaffold, holding the above-mentioned tools as well as my phone/camera, so I didn’t have an extra hand to show packing the mortar in!
If you’re careful and don’t make a mess on the brick faces, you might be done at this point. I like to use a water-diluted muriatic acid to wipe any haze from the brick faces a day or so after the mortar has set. (Muriatic acid is NASTY stuff and very dangerous. You should not breathe it or get it onto skin, and certainly not splash it into your eyes. If you use it, be SURE to wear eye protection and long protective rubber gloves.) Try to avoid getting too much onto the mortar joint. This picture is prior to wiping any haze off:
Here’s the muriatic acid. I used it at roughly 1 part to 10 parts of water.
When all was said and done, I “painted” the repaired area using Thomson’s Water Seal. I think that little extra effort will help prolong the life of the work.
Here’s the final result:
One more thing. If you happen to have Type N mortar mix that you want to use, or for some reason, can’t obtain Portland cement, you can use 8 parts of Type N mortar mix with 1 part of hydrated lime and 3 parts of fine sand. That will alter the components of the original Type N mortar mix to mimic the proportions found in Type O.
I hope all your projects go well. Thanks for reading, and happy restoring!
Ed
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