Fixing Common Concrete Floor Problems

Fixing Common Concrete Floor Problems

Written by nick

Topics: Question & Answer


I watched a couple of your videos on YouTube and like your work. Thanks for the ideas you share. I wonder, if not too much trouble, can you give me any advice on a concrete basement situation I face? I know I am way out of your region so if you are busy and can’t respond, no problem.

I am in an area of Boston that was hit hard in 2006, 2008 and 2009 with record breaking flooding. My place was almost entirely free from any impact. With flooding in several homes in my area, my basement stayed 100% dry from water, except for 2009 where water levels rose higher than recorded New England weather history. The only water that got in the basement was a puddle about 2 feet square 10 feet away from the foundation wall. After that dried up in a couple of days, I saw a weak area in the concrete, not a clear hole but where the strength of a small area about the size of a pencil showed slight crumbling. Also, in several other areas of the basement, a white powdery substance, kind of chalky, like a residue, shows up as well. I was going to paint the basement but then saw your interesting site on staining. But before I do anything, I was not sure what the whitish stuff is or how to strengthen that small compromise on the floor. If you have any advice and time your feedback is appreciated!

Lee of North Reading, MA

Thanks, Lee


It’s great that your basement was able to stay mostly dry during all of the flooding in your area in the past years. Water intrusion from walls or floor is a leading cause of basement flooding in many homes.

The white chalky type residue that you see on the surface of your basement floor is called efflorescence. When moisture migrates through the concrete, it can pick up calcium salts from inside the concrete slab. The moisture then reaches the surface of the floor, evaporates, and leaves these salts; causing the white chalky residue on the surface. This can be cleaned form the surface using a dilution of 1 part distilled vinegar to 5 parts water (increase concentrations for problem areas).

There are many ways to test your concrete for structural integrity such as core samples or hiring a structural engineer to assess your floor. This is the most accurate way to assess your concrete floor but can be very expensive and is usually not necessary for residential projects. The problem you are having is probably the cause of bacteria in the porous concrete. These bacteria feed off the nutrients of the concrete with a waste product of sulfuric acid which will eat holes in concrete.  You can also take a simple framing hammer and slightly tap the concrete where you suspect weakness in the concrete. If the concrete is weak the hammer will crack or chip the concrete. If you have a spot that is very weak it should be repaired prior to any additional work. Remove the concrete that is weak and replace with proper strength cement. For a small area you may just need to clean the area and apply a patching compound; for sever areas remove the surrounding concrete and replace with new.

Painting your basement floor can seem affordable and a quick and easy fix to “spruce” up a basement, but properly staining and sealing a concrete floor will last many more years and provide much more aesthetic benefits. Thanks for the question and good luck on your project.

We want to come over and talk about your concrete project. Schedule a free estimate by emailing or call 260.748.2252 (It really is that simple). Let us show you what is possible with concrete in your home.


Nick Dancer

Fort Wayne, IN -260-748-2252


Leave a Comment Here's Your Chance to Be Heard!