I am in just finishing repairing and repointing brick steps like the ones
shown in the following YouTube video:
I made a bit of a mess while doing it, so I am going to want to remove the
excess mortar stains and film that I left on the bricks. My plan is to use
muriatic acid, and I may buy this stuff -- Kleen Strip muriatic acid --
from Home Depot:
However, I would like to get some more specific instructions or find a good
YouTube video that explains how to do this mortar clean-up.
I am not sure how much to dilute the muriatic acid, and I don't know whether
to spray it on, or just brush it on, or whatever. Unfortunately, none of
the YouTube videos that I could find actually showed how to do this.
My plan right now it to wet down the steps with water, then dilute the Kleen
Strip muriatic acid to about 1 part acid to 4 parts water, brush it on, let
it sit for a few minutes, then rinse it off thoroughly with a hose.
Any other help, ideas, or suggestions would be appreciated.
When I took a short bricklaying course about 20 years ago, a trick
bricklayers used was to nail a piece of level loop nylon carpeting
around a short piece of 2X4 lumber, and use that as a brush to scrub the
soft mortar off the brick face as they laid the bricks. Because the
mortar joints are recessed from the brick faces, the carpet will scrub
the brick mortar off the brick faces without scrubbing it out of the
I would try using a paint scraper to remove as much of the dried brick
mortar from the brick faces first. Watch to ensure the paint scraper
doesn't leave marks on the bricks. If so, switch to a paint scraper
with a tungsten carbide blade. If push comes to shove, full strength
muriatic acid will remove any marks the metal leaves on the bricks.
The instructions you linked to say for brightening masonary and brick
work, mix 1/2 pint of acid per gallon of water, which is far less than
the 4:1 you were intending to use. If it were me, I wouldn't start with
any more than a pint of acid per gallon of water, or about a 8:1
dilution ratio. You can always add more acid if it's not strong enough
and doesn't seem to be doing anything. Try that on a small area and
scrub with a toilet bowl cleaning brush to see the results.
The acid brushes they sell in brick supply places look kinda like a big
toilet bowl cleaning brush with yellow polypropylene bristles about 3
inches long on one side only. I'm thinking you can just use a toilet
bowl cleaning brush for a small project.
Then spray the whole thing down with your garden hose or a hand pump
garden sprayer and allow to dry. Maybe wipe up any water puddling with
Thanks. I should have explained it a little better. There aren't any
excess pieces of mortar left on the bricks because I brushed the excess off
before the mortar dried. But, there is a lot of white mortar-stained areas
on the brick -- a translucent thin film of what was mortar and water. I am
assuming that the muriatic acid will react with that and dissolve it and
then can be rinsed off with water.
Yes, what they describe is about a 16:1 dilution ratio to "brighten" masonry
and brick work. But, even though on the lable there is a mention of
"removing excess mortar", there are no instructions on whattype of
concentration to use for that. Maybe I'll try starting with about an 8:1
ratio first as you suggested.
The label is also confusing (to me) about what the concentration is of the
muriatic acid that is in the bottle. It says something about 20%, which I
assume means by volume, and then says it's 31% by weight.
I don't know what strength regular muriatic acid is, or what strength brick
masons use for this type of clean-up work after repointing brick with new
mortar that isn't fully cured.
You're talking about stains and film I gather. ;=)
Not actual excess mortar, I only know about getting actual mortar
I'm not sure if everyone would have called it excess mortar and the
house looked pretty good until I looked closely, and then I was bothered
one day by many places where the mortar overflowed the space between the
bricks. It had the normal depression, channel, groove, but there was,
as I say, stuff ovelapping the brick below the mortar layer, and maybe
even the brick above.
I used a hammer and cold chisel. And eventually jus a hammer, after I
learned how hard to hit it so the excess mortar broke off but the
nothing else was bothered. I spent a couple hours at this, and only
did from 1 or 2 feet high to 5 or 6 feet high, and only 5 or 10 feet
horizontally. But only the first floor is brick. I didn't get much
of the side or any of the back of the house, but I got the part I see
every time I come home, and I haven't noticed the extra mortar since.
Those strengths are the norm. Just use one part of that to "X" parts of
water. And ALWAYS add the acid to the water, NEVER vice versa.
Start with a very weak mix...if that doesn't work for you, increase the
strength until it does. What you want to remove probably won't require
more than a very weak mix.
Thanks. I'll try that -- probably in the next day or two. I'll post how it
I may try posting a 'before I started the repair" photo, an "after my sloppy
repair job and mortar work", and an "after the muriatic acid clean-up"
I did such a crappy job with the mortar that I am a little reluctant to post
how it looks, but I may post it anyway.
One side note: When trying to do the repointing, I tried buying and using
mortar/grout bag like this one to apply the mortar in between the bricks:
I couldn't get it to work correctly. The problem that I had was that the
only way that I could get the mortar to come out of the bag reasonably well
was if I made the mortar too liquid and soupy. Anything thicker than that
was almost impossible for me to get to come out of the bag even while
squeezing hard. It would just get clogged in the opening. I tried cutting
the tip to make a larger opening but that didn't help much. And, I did mix
the mortar well so there were no clumps. I finally just gave up and I
decided to apply the mortar by hand -- hence the sloppy mess that I now have
to try to clean up.
Couldn't get that URL to work, ended up on Halloween Decorations, so gave
However, I use the type S mortar mix from HD. Very difficult to insert the
mortar into cracks. So I made my own method, used a plastic funnel cut
down, and simply squeegee the mortar to kind of where I want it to go.
Probably lose half of what goes up. But a stiff brush removes the damp,
not set yet, mortar.
PS: my mistake was not knowing you're supposed to 'slake' the mortar [if
that's the correct term] let it sit, 10 minutes, mix again and THEN use.
Once I learned that [directions as shown on grout mix!] really made a
difference! The type S mortar changed consistency and started acting like
mortar instead of wet sand.
Sorry the link didn't work. If you want, you could go to HomeDepot.com and
do a search for,
Blu-Tip 12 in. x 24 in. Grout Bag , which is what the item is called.
I didn't use the Type S mortar ( Quikrete 80 lb. Type S Mason Mix ). I used
the regular mortar mix ( Quikrete 60 lb. Mortar Mix ).
I thought that I waited a little after the first mix, and then re-mixed. I
definitely did that when I couldn't get the first batch to go through the
applicator bag -- because I emptied the bag back into the mix that I had,
re-mixed it again with a little more water, and tried that. But maybe the
next time that I try it, I'll try the "slake" the mortar, wait 10 minutes,
then mix again, and then use.
Or, maybe regular mortar mix is more sand-like and not as smooth to work
with as the Type S mortar -- which I didn't try. The funny thing is that
the only reason that I didn't buy their Type S "Mason Mix" is that it comes
in 80 pound bags rather than the 60 pound bags that the regular mortar comes
in. I just didn't want to have to lug around 80 pound bags. If it came in
smaller bags, I would have bought that instead.
> Or, maybe regular mortar mix is more sand-like and not as smooth to work
Here in central Florida, it comes in 60# bags at Home Depot. Lighter but
still not feather-like. That's why I use a cane :) Cane doesn't help at
home though :(
They may well have more than one packaging...mine says - IIRC -
"Mortar/Stucco Mix, Type S". A bit over $6.00/bag.
I know cement based grout needs to be mixed, slaked and then mixed
again, but I've never heard you should also do that with brick mortar.
I can see no reason why that would do any harm, tho.
If you find your brick mortar dries up too quickly, it's because the dry
bricks are wicking moisture out of the mortar. What helps a lot is to
add hydrated lime to your mortar when mixing it. The lime hangs on to
water and prevents it from being wicked up by the bricks, making your
mortar remain workable for a much longer period of time. Adding lime
will weaken your mortar because it reduces the percentage of portland
cement in it, but the hydrated lime you add ends up turning into
limestone (calcium carbonate) with the passage of time, and in most
cases mortar as strong as limestone is plenty strong enough for
Just a quick update...., the muriatic acid worked fairly well -- kinda fun
to use. I initially mixed it 50-50, meaning 1/2 water and 1/2 the 20%
muriatic acid that I bought at Home Depot -- that made in about a 10%
muriatic acid mixture. That was working fairly well, so I tried making it
even stronger by adding more of the 20% muriatic acid and less water. That
worked well too.
I wet the steps first with water, then brushed on the mixture, let it sit
there and do its thing for a few minutes, the brushed it a little, then
rinsed it off.
I have a little more brick pointing touch up etc. to do and I am going to
re-paint the railings, but we have rain for the next 2 days, so I'll finish
it after that. Then I'll post a few before, during, and after photos.
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