Hello All,

Wanted to get some input from the group regarding the brick stoop on the front of my house. I'm in the process of grinding the mortar joints to prepare for re-pointing. Most of the mortar joints on the steps and landing (Horizontal surfaces) are 3/4" to 1" wide. I believe the norm is 3/8"?? On to my question: I wanted to know how deep I should grind these joints. I've read 3/4" deep, and I've also read 2 1/2 times the width of the joint. Has anyone faced a similar situation, namely grinding out a wider joint? If so, how deep did you grind? To put it another way, if this were your project, how deep would you grind the joints? Also, anyone have any suggestions/techniques for grinding a wider joint? My angle grinder's grinding wheel is 1/4" thick, so, grinding a wide joint with this is not fun. This project is not fun no matter how one looks at it, but, it's got to be done.

Thanks

 

Perhaps a diamond or carbide masonary blade on a Skil saw would work. just make a cut on both sides of the joint and then chip out the middle with a chisel.

 

Thanks for the reply,

I hadn't thought of that. Good idea! What about depth, do you think 3/4" to an 1" would be enough?

 

I've never re-pointed brick so I'll leave that for someone else. I would guess that you would want them deep though.

 

Thanks again....I don't know much about brick work myself, but I have worked extensively with concrete. That's a different animal. Maybe someone with brick experience will jump in...

 

It's not clear to me why you think all of the joints require complete removal (grinding) of mortar. I've repointed a lot of brick work, but all of it only required just removing the unsound stuff, and not everything. On average, far less than 30% or so. Unless all of your mortar is uniformly unsound and crumbling, maybe you're making more work for yourself than absolutely necessary.

 

You make a good point, and all about not doing extra work unless I absolutely have to. Almost all of the long mortar joints on the landing had a crack on one side of the joint or the other, running the length of the joint. Just for a test, I tried using a suitable caulking on one of the cracks. It just plain looked unprofessional to me. I bought this house last November, built in the 70's. I suspect the stoop, based on the condition of the mortar, is at least that old. My plan was to only grind and re-point the horizontal surfaces (The landing and 2 steps). The vertical surface joints are in pretty good shape. So, this is NOT a complete grindout job.

 

Bridgeman45 - Here's a pic of the landing. I've done some grinding already. Do you think a 1 inch depth grind would be acceptible for this? You say you've had experience with re-pointing, did you ever grind a wider joint? If so, what did you do?

Thanks

 

I've ground a few brick joints in my day, and vowed to never do it again. Way too much dust (even with a large box fan set up to blow it out of the immediate work area), and too hard on my precious angle grinders. And I've never felt a need to grind adjacent bricks to make mortar joints wider--way too anal for me.

For prep work, I've relied on the old hammer and chisel routine, first doing a visual to remove all the obvious loose stuff, then dragging the chisel along the joints until the difference in sound told me there's still some unsound mortar that needs to come out. I personally think a rougher surface is more conducive to getting new mortar to bond with old material in the joints, which is another reason not to grind excessively.

I don't see anything in the photo that I would do differently, other than chipping a few diagonal gouges into the smooth ground surfaces.

 

Sounds like you've been around this stuff and know the pitfalls. You're so right about the dust. I like the suggestion about diagonal gouges. And you're right about a rough surface makes for a better bond. What I've done so far is grind a 1/4" groove on either side of the 3/4-1" joint, thereby leaving 1/4-3/8" groove in the middle to chisel out. I certainly wouldn't grind the brick either. It would have been easier for me if the builder of the stoop had used more of a standard width mortar joint, say 3/8", But such is life. I've got a good handful of projects on my plate, so, I gave this project a lot of thought before I decided to tackle it. My perfectionistic side said: grind & chisel all the joints so when the re-pointing is done, all the mortar color would match. My pragmatic side said: Only do what's absolutely necessary with an arduous task like this. So, I'm opting to do only the landing & steps. In your experience, how did you go about matching the coloring of new mortar to old? Let's say you only need to replace a portion of a joint. Or, you had to replace a cracked brick?

Also, I picked up on what you said about dragging a chisel along a joint looking for unsound mortar. I'll remember that one.

Thanks...

 

I've rarely attempted to match mortar colors, as the vast majority of my tuckpointing work was on brick chimneys above the roof line--from the ground, slight color differences are not visible. In your case, where things are obviously more visible, it may or may not be an issue. You can experiment a bit by mixing up a small test batch of the mortar you plan to use, and if it's too dark for the majority of the surrounding joints, splurge and buy a sack of white Portland cement to come up with a better-matching, custom mortar. Obviously you'll also have to buy mason's sand and lime to mix up an acceptable blend. Don't use all white Portland, because it will cure out too white, standing out like a sore thumb--ask me how I know!

If I were you, I'd give serious thought to giving everything a double coat of Kure-N-Seal after a diluted hydrochloric acid wash and clear-water rinse. The K-S will really bring out the brick color, which will take away the impact of any slight mortar color variations, and it will make everything far more resistant to future weathering damage.

 

Thanks much for your input on this. Do I have to wait 30 days (for the curing process) or so after I re-point before I use K-S?

 

No need to wait--the "Kure" part of the name is the hint that it's both a curing compound and a sealer. Intended to be applied to concrete/mortar in the semi-fluid state. It will be more effective if you wait a few weeks or a month between coats, and don't put it on too heavy (has been known to "yellow" with a thick build-up). There are several variations on the market, so make sure you pick one that's compatible with the lime in mortar. I've found the best way to apply is with a pump-type garden sprayer, nozzle set to a fine mist.

 

Thanks again for the input and suggestions....