Repair of deteriorating concrete steps - advice or suggestions?

[roger2]

One of my current projects. Before winter I want to fill the voids in these steps to seal out moisture and thus prevent continuing damage.

My thinking is to use mortar and (where necessary) use broken chunks of brick to fill the voids and make a new surface flush with the old surface. Then, either sooner or later (depending on curing time) the entire step unit would receive a surface coating/sealant of either paint or perhaps something better that someone might suggest.


Questions floating around in my mind presently:

1) What would be the best thing to use to bond to the old surfaces? Of course I will clean away dust and loose bits. I have some Type N mortar from a previous brick laying project. Would Type N work well? Is there something more specific to this type of application that might be better than Type N mortar?

2) How much curing time wold be needed before applying a sealing surface coating?

3) What would be the best type of surface coating? Exterior floor paint? Is there something else?

Thanks in advance...

 

[sol7]

I would do a parge coating. 2 parts mortar mix type S and 1 part portland cement. I usually mix in some bonding agent too. The big hole will need a couple layers. 24hrs between layers. The one in the front can be done in one shot. Rough up the first layer after applying, if you are going to put on a second layer, for better grip of the second layer.

Oh, make sure to get all the loose stuff out of the holes.

 

[lifer70]

sol7 has the pro way to do it.

Me, not being that knowledgeable used kwickcrete patching compound to fill in the voids. Once it was cured i used Rustolium deck and concrete restorer to color and seal the entire step.
Turned out nice.

 

[Champco]

I repaired much more corroding concrete steps just like that. It looked hopeless but after three years it is still holding. using your fingers remove all the loose stuff you can before patching it. Some of that cement with Vinyl patch stuff may be ok. Mix it thick.trowel it in.

 

[roger2]

Hey....already did the project a couple weeks after my original posting. So @sol7, it was done before you posted. I very much appreciate everyone's input

I used Quickrete FastSet Repair Mortar. It took 5 or 6 bags to do the job.
https://www.quikrete.com/pdfs/data_sheet-zip and mix fs repair mortar 1241.pdf

This product comes in a zip-lock bag which, according to the directions, is to be used for mixing the mortar by kneading after water is added. For what its worth, I couldn't get it mixed that way. I had to add a bit more water than indicated, and also used a small drywall mud pan for the final mix after beginning the process by kneading inside the bag as per the directions. Once mixed to (what I felt was) the proper consistency, the product was easy to work and gave just enough set time. No issues with it running or moving after I troweled it in.

Before mudding I did clean away loose material with a wire brush and also a bit with a long thin chisel. Also cleaned surfaces with a special Quickrete cleaner, which probably was not necessary, then sprayed it with a hose. In the deeper hole I did use two layers with some broken bits of brick embedded into, and sticking out of, the first layer so there was something for the final layer to grip to.

Came out pretty good. For this winter I think this repair will at least prevent further deterioration. Next spring or summer I will scrape it, caulk small cracks, and paint it up nice. I will look into the Rustoleum product mentioned above. Other paint suggestions are welcomed as well.

 

[savatage1973]

What sol7 recommended is by far the best method, but what you have done looks pretty good and should get you through the winter. I would get some paint/sealer on it sooner, rather than later, as winter weather and salt/de-icer will rapidly take its toll on the "naked" repair areas. Any exterior porch/deck paint or garage floor/concrete paint will work--I'd recommend adding a little sand to the paint/sealer when applied as an anti-slip agent--just straight up paint gets slick with water/snow on it.

 

[roger2]

I am wondering about curing time. The deepest area, not shown clearly in the pics, is around 5" deep. How long will it take, in cooler weather, for the patched areas to fully cure?

Should the patch material be completely cured before sealing it with paint?

 

[sKiZo]

All of the above.

- Clean out any loose, old concrete. Good to chip out anything that's discolored for the best bond.
- Blow out any dust with either a compressor or canned air.
- Chisel out the perimeter so the bottom edge is indented. This will keep the patch from popping out.
- Brush the area with a good bonding agent.
- Mix a bit of the same bonder into the concrete mix.

For small areas, I use an expanding concrete as that will lock into the old stuff better. Just be careful to smooth it before it hardens as the stuff can be a PITA to grind or level once dry.

* The bonding agent is available most any hardware store. Quikrete ain't bad, and a quart goes a long way.

PS - I'll also brush down the patch with the bonder before painting for better adhesion. Let it dry and rough it up a bit with a wire brush.

 

[sol7]

You should be good for painting after 30 days. As mentioned above, any good porch or garage floor paint would be good. Sprinkle with sand while wet or mix sand into the paint. I prefer oil based vs water based latex for anything exposed to the weather. Epoxy would be better. Not sure if the weather is going to be warm enough now to allow painting.

 

[roger2]

And I am still a bit uneasy about the curing. Color of the patched areas is still not uniform. It has been cool here, below freezing a couple times but mostly 40'ish give or take, and one of those patches was very deep. As for weather going forward, Indiana weather at this time of year is a roll of the dice.

I will consider adding sand. But what grade of sand would be appropriate?

I also intend to research other methods of adding traction as I have seen various things used (mostly) in commercial applications. This is a rental property and all of the residents (including myself) are older so risk of a fall needs to be mitigated.

 

[sol7]

I hear ya about the the weather.

You could forgo the painting. One winter isn't going to kill it. As far as the sand, just play sand is fine. If you hold out on painting, there are glue down or self-sticking anti-slip/skid strips.

 

[roger2]

Yeah I want to look into those anti-slip strips. I have some other, non-painted steps that could use something too. Haven't had time yet, I am just kind of swamped with other pre-winter projects....same as every year at this time. Not complaining though, it feels good getting things done before winter sets in...

 

[sKiZo]

Probably too late, but concrete does not like cold. Anything much below maybe 40F and it will cure weak. There's special additives pros use to help it along, but best to be avoided, even if you insulate the new work.

Then again, I tend to ignore my own advice and spin the wheel when I want it done, and done now. The last center section of this walk was poured with a cold snap and hard frost coming the same night, so wish me luck, eh.

 

[roger2]

Directions for the product I used said "Protect from freezing for 24 hours", which I did. And to clarify, I didn't just do the patching, it has been maybe 3-4 weeks or so since I did it. I am not worried at all about the patching that is already done. I do wish you luck on yours sKiZo

Moving forward, I am interested in decision making information for the remaining steps of the project, regardless of whether I proceed now or later



Thanks again for everyone's contributions to this thread thus far

 

[savatage1973]

Not sure if the weather is going to be warm enough now to allow painting.

Believe it or not, you can paint (exterior) in the dead of winter. I am a contractor, and we do a fair amount of fire/water restoration work. There are products (from different manufacturers) that we refer to as "ice paints"--they can be applied and will "cure" rather than "dry" at below freezing temperatures. House fires occur year round (actually more frequently in the winter) and you can't wait til spring to put things back together--these products aren't cheap, but they work.

 

[cgutz]

I had that problem on our first house. Left it in place, removed the railing, and built a nice looking treated wood steps over them.

 

[Champco]

Concrete never really does stop curing does it?

 

[savatage1973]

Concrete never really does stop curing does it?

From a vo-tech training manual:

"The most important aspect is to keep the concrete moist. When moisture is removed hydration (the chemical reaction in the cement) ceases and curing essentially stops. It's worth mentioning that it's near impossible to fully remove moisture from anything in our climate outside of an oven/desiccator. For that reason concrete will never stop curing entirely if it's left to 'dry out'. It may never cure to the required strength especially if the drying occurred within the first 24 hours however.
,
Before chemical curing agents were around concrete had to be physically protected from evaporation with covers to ensure hydration continued. This obviously prevented further construction. Now curing agents can do essentially the same thing but allow the slab to stay open. As long as the slab has sufficient early strength to support the required tasks there is no increased risk to the structure."

One important distinction that needs to be made is the difference between "drying" and "curing". Modern concretes employ many different chemical "curing" agents to increase set rate, strength, and ability to be poured at very low (even sub-freezing) temperatures. Concrete can even be poured in the rain and under water, as long as the water is displaced by the mass of the material. "Curing" is a chemical reaction, not a "drying" process. "Drying" is what you see as the color changes from the "wet" appearance (as water evaporates or is consumed as a result of the chemical reactions). Concrete that still looks "wet" may actually be sufficiently "cured" to walk on within a couple hours. It is common to see contractors spraying water on driveway or sidewalk slabs when poured--that is done to keep sufficient moisture present for the curing process and prevent cracking of the surface, especially on hot days and/or direct bright sunlight.

Sorry for the lengthy technical primer, but just thought I'd share...

 

[pdm4606]

You got "concrete termites" and they are viscous.
Will destroy steps in a few years. Best bet is to rent a jack hammer and do it over.
I had a similar situation and ended up building all new from pressure treated concrete. Almost looks like wood.

 

[Champco]

From a vo-tech training manual:

"The most important aspect is to keep the concrete moist. When moisture is removed hydration (the chemical reaction in the cement) ceases and curing essentially stops. It's worth mentioning that it's near impossible to fully remove moisture from anything in our climate outside of an oven/desiccator. For that reason concrete will never stop curing entirely if it's left to 'dry out'. It may never cure to the required strength especially if the drying occurred within the first 24 hours however.
,
Before chemical curing agents were around concrete had to be physically protected from evaporation with covers to ensure hydration continued. This obviously prevented further construction. Now curing agents can do essentially the same thing but allow the slab to stay open. As long as the slab has sufficient early strength to support the required tasks there is no increased risk to the structure."

One important distinction that needs to be made is the difference between "drying" and "curing". Modern concretes employ many different chemical "curing" agents to increase set rate, strength, and ability to be poured at very low (even sub-freezing) temperatures. Concrete can even be poured in the rain and under water, as long as the water is displaced by the mass of the material. "Curing" is a chemical reaction, not a "drying" process. "Drying" is what you see as the color changes from the "wet" appearance (as water evaporates or is consumed as a result of the chemical reactions). Concrete that still looks "wet" may actually be sufficiently "cured" to walk on within a couple hours. It is common to see contractors spraying water on driveway or sidewalk slabs when poured--that is done to keep sufficient moisture present for the curing process and prevent cracking of the surface, especially on hot days and/or direct bright sunlight.

Sorry for the lengthy technical primer, but just thought I'd share...

In the 1980's in phoenix were worked in newly placed manholes which came in sections and were 30+ feet under ground in very hot weather conditions. They smelled new for years as the concrete cured. Low air circulation unless we were in em. They often filled with water as well.