Painters sprayed the foundation wall (poured concrete) over the weekend and the paint is already peeling off and rust showing through from the metal cross pieces that held the forms together. I believe they used the same paint as they used for the wood trim. Shouldn't they have used a concrete-specific stain that actually absorbs into the concrete? I'm assuming a stain can not be used now that there is a layer of paint, correct? What are my options now? A rubberized sealer?

What is the best way to ensure the metal pieces don't continue to rust? Seal the areas with caulk? Does the rust need to be neutralized prior to caulking? In addition to painting/coloring the foundation, I would like to seal it as well, which is why I like the rubberized coating idea. There are countless voids and tiny holes that are undoubtedly going to flake off over time if something isn't done.

Are any of these products any good? UV resistance is important because it will be applied to the exterior wall.

https://www.homedepot.com/p/Flex-Sea...-301711550-_-N

https://www.amazon.com/dp/B00LMMFX9I...a-404339247767

https://www.thepaintstore.com/Rust_O...e_p/276368.htm

 

For the most part stain only works over bare concrete. Nothing wrong with using house paint on the foundation. Typical siding paint is usually better quality than typical masonry paint. They should have used a primer! How long ago was the concrete poured? Have you discussed the paint failure with your painters?

 

Not sure what the rubberized sealer would be used for but similar to my lentils for the brick I just used a rusty metal primer before painting and they are good 10 years now!

 

Somehow I missed that As Marq said, all steel/iron needs to be coated with a solvent based primer and preferably an oil base finish.

 

Quite honestly, the entire area of the foundation wall that was to remain above ground should have been "parged" with a cement-based product to embed the ends of the reinforcing steel (used to hold the concrete forms together) inside and away from the weather. This parging then needed to cure for a period of time, maybe as long as a month or more, before being painted.

At this point I think you will need to scrape as much of the paint off as possible and then let it go until next spring or summer. At that time you can use something, maybe even aluminum paint, over the rust stains and after a suitable drying/curing time cover everything with a high quality latex or PVA enamel.

 

I've had good results painting stucco 3 days after it was applied. There is a big difference between a decent house paint versus using a masonry paint. As far as I know parging and stucco are the same. It's always been my understanding that concrete needed to cure 30 days before you should paint it.

 

Mark is the painter, not I. My information is mostly from my daddy and he's been dead for more than twenty years. I don't know why stucco should be ready for paint in 3 days when it takes ten times that long for concrete, the only difference between the two materials that I am aware of is that stucco has lime in it just as does mortar.

At any rate, my information may be sadly out of date but at one time that was the way it was done. I'm quite sure it will still work that way if you want to take the time.

 

The concrete wall was poured in August, so it's definitely cured by now. They didn't clean or prime the wall prior to painting it. They just went ahead and sprayed it with paint off the bat. You said to remove as much paint as I can now and then wait until the spring? Any harm in leaving it as-is? It will look really bad if I have them scrape paint off. Should I caulk over the rusted areas to prevent further corrosion until spring?

 

I don't see any harm in leaving as it is for now. More likely as not it was the lack of cleaning that caused the problem. I don't know that I would even bother with the rust now unless it REALLY bothers you. If it does then just some wire brushing and dab some paint on the steel should hold until you can do a better job.

When you do paint it be sure to clean the surface before hand. I personally would use a brush to "work" the paint into the concrete rather than using a spray. If the weather is conducive to painting (probably not) then you could do the work now. Best to not have temperatures drop much below fifty for the paint to dry properly.

Mark may have other ideas, he has far more experience and much more recent experience than I.

 

It's not that the rust bothers me, I just don't want it to get worse. If those metal pieces rust out, then their will be a void and the concrete will start to chip away in those areas, will it not?

I had them paint a section of wall on the opposite side of the home because the paint was in pretty bad shape. They had already put their spray gun away, so they did this section with a roller and a brush. It will be interesting how this side holds up in comparison over the winter. Nighttime temps are dipping down into the 20s in the next day or so, so I'll touch up the rusted areas and hold off until the spring (and hold off paying the builder until it is done properly).

 

I've never seen nor heard of the tie rods rusting out and leaving a void but I suppose it could happen. Any that I saw were made so that when the forms were stripped the rods were snapped off slightly below the surface and then the divots were parged, solving the problem.

 

I suppose I'm being a little dramatic. The goal is to stop the rust so it doesn't get worse and starts leaving unsightly streaks down my white foundation wall.

 

I used to work for an outfit in fla and we painted 100s of stucco houses a year. We never had any issues with painting them after waiting 3 days. I have seen issues with paint jobs where the painter waited 7-10 days and didn't use a primer, just 1 coat of masonry paint.

All sprayed paint [other than on metal] should be back rolled or back brushed to work the paint into the substrate. The only way to stop rust is to have a barrier between it and the latex paint. An oil base primer is bare minimum but might be enough.

 

Okay. So what do you recommend I do NOW to seal off the "tie rods" (more like thin bars) to stop the rust until it can be painted properly in the spring? In other words, do I need to neutralize the rust that has formed to prevent it from getting worse, or will simply sealing these locations with caulk suffice?

 

This is what they used to tie the forms together. Most if not all of them are visible from the exterior and are rusting.

 

Are they actually sticking out? They are supposed to be broken off (bend back and forth a few times) where the notch is and that should be just below the surface of the concrete. I would wire brush any rust on them now and then paint them with aluminum paint. Rustoleum metal primer would be better but I doubt it would dry in the colder weather. Aluminum paint is extremely runny and dries quickly.

 

I'd clean them up the best I could and wait for a decent day to apply a liberal coat of a rust inhibitive primer over them. Aluminum paint doesn't always hold back rust.

 

They aren't "sticking out", but they are exposed and the rust is bleeding through the paint. I'll scrape them clean and apply a primer as recommended and have them do it properly in the spring.

 

I would hit them with a grinder to recess the steel into the concrete then caulk over them with a polyurethane sealant like NP1 or Sika. Then paint the caulk.

 

Sounds like a plan. Thanks!

 

The painters came back out this morning and said they are going to power wash the wall, scrape off any loose paint, then apply a coat of oil-based concrete stain. I don't understand how a stain is going to penetrate a latex paint. Doesn't a stain need to be used on bare concrete?

 

I'm not so sure about apply an oil base stain over latex. Might be ok if most of the latex comes off when they pressure wash. Oil base stain will bind better to chalky surfaces. Most any coating sprayed over concrete does better if it's backrolled [helps work it into the substrate]

 

It doesn't appear they did much of anything. Definitely not 2hat they said they were going to do. I highly doubt they plan/planned on removing all the paint. Sounded like they were going to power wash it to remove dirt amd scrape off any loose paint here and there. I honestly can't tell a difference. Still needs to be corrected. Maybe they'll get it right the third time.

 

If you use enough pressure latex paint is prone to be removed by pressure washing - more so than oil base. I'd feel better about the oil concrete stain if most of the latex was removed first. Did they say why they thought the paint peeled? My offsite guess would be they painted over dirt/dust.

 

They didn't have an opinion. I gave them my opinion (paint didn't adhere properly because of spray applied to concrete forms) and they neither confirmed nor denied. And it appears that they painted over dirt in some spots. Of course they denied that, but it is pretty obvious to me. You can see the dirt through the paint in a couple areas, but there wasn't any dirt in this other area that is peeling. I really think it was a lack of preparation. They should have power washed the bare foundation, let it dry, applied a stain, or applied a primer followed by a coat of paint. That isn't what they did. They MAYBE washed it (I don't believe they did) and I believe they painted with Sherwin William Resilience latex paint. I wasn't paying close attention, but I don't recall hearing or seeing a power washer, and I saw them carrying a can of that paint.