PROBLEM PAINTING CONCRETE FLOOR

You do reallize this is an engineering forum?

Perhaps you should google a self help, home repair, do it yourself or other forum?

Guset #1 Don't shout

Guset #2 - Painting is equally an engineering subject. The position (basement) is not important. we are struggling in-fact in getting a durable paint to paint our factory floor.

If you google- Epoxy floor paints- you may get guidelines for surfacte preparation. But you have to prepera it in line with standard procedure- clean all the rust, oil and foreign materials and so on.

For this usually thinners and other chemicals are supplied by the paint manufacturer.

Based on your geographic location you may contact reputed paint manufacturer with the problem.

That is the best methdology.

Your forum should have been in chamical & Matl sc or Civil Engineering. Though I think those guys too have a look at this part.

Good advice about the Civil Engineering forum. Beyond that, he might want to have a structural engineer look at his basement. He might need to find out why he has rust on his basement floor.

Paint manufacturers make paints for different surfaces. The most common paint is wall paint for most walls. I have used special paint for restroom walls, and a special primer for cinder block or concrete block walls. I have also seen floor paint used, which is made for concrete and is supposed to be able to withstand traffic. If he didn't use floor paint that would be why it didn't stay. If he did use floor paint, moisture that causes the rust would prevent the paint from sticking, and he needs to find out why he has that much water coming into his basement.

Another thought: he might want to check to see if the basement was built to code.

May be required to chip the top layer off and put waterproof cements. (Just a wild guess - dont know AB of C_{ivil Engg} But that way painting won't be a trouble.

Citric acid or oxalic acid will remove rust from concrete without damaging the concrete.

I am assuming the rust has come from filings, grinding material etc and not from deterioration of your reinforcing.

Before you paint, you need to remove loose rust and the ingrained rust. Even if paint sticks to it, the rust is poorly anchored to the concrete and no coating is any better than the base it is applied to.

As suggested, check into flooring paints from there.

The paint you use will depend on your use and loadings. The alternatives include chlorinated rubber (not very good wear resistance, but tolerant of poor substrates), polyurethanes (often hard, wear resistant, often expensive, sometimes not resistant to weather exposure although some are) and epoxies (wear and slip resistant, sometimes expensive, often not good UV resistance but many can be mixed with sand and used like concrete as a topping to repair damaged surfaces)

There are numerous variables and you need to get detailed advice from paint suppliers.

Good luck

Muriatic acid used to be the cleaner of choice for concrete, but I would advise you to rent a good high pressure water spray type washer. The solvents and pressure do an excellent job of cleaning (you will be amazed) and you won't be knee deep in water quickly since the nozzles are pretty tiny.

Be careful about spraying a person though; they can do some damage.

Then a paint or epoxy labeled for application to cement floor will adhere just fine.

If you were hoping to get a lead on a paint that doesn't require a clean dry surface, please let us know if you come across one. You will save the painters among us a lot of prep time in the future.

Then there is the matter of the source of the rust. Some concrete in direct contact with earth gets water right up through the concrete. A 'vapor barrier' should have been installed before the basement was poured, but nothing is perfect.

Also we have no idea what part of this big earth you are located in, and that could have a lot to do with how to proceed. Climate, humidity, water table, age of structure - so many things. Live on an island? salt comes up through everything structural etc.

Hope we have helped some. Let us know when you win this one. CJM

G'day, If the floor has been "sealed" in the past, you cannot use a water based concrete paint as it will not grip. You must use an oil based paving paint paint. As for preparation, a dedicated etch concrete primer (produced by White Knight in Australia) or a solution of Hydrochloric acid. The paint manufacturer will specify the recommended proportions.

RRV