cinder block

[diyunending]

Hi,

I'm new to this but sure can use help. Our interior basement cinder block has been painted and constantly 'sheds' paint 'dust' onto the surfaces inside the room. What can I do to somehow seal the wall or cause the paint to stop shedding?

diyunending

 

[readhead]

My first impression is moisture is coming through the wall from outside. Unfortunately the way to fix that is to dig around the house and water proof the foundation. I may be wrong but that is the most common cause for your problem.

 

[Dan in Pasadena]

FYI: You almost CERTAINLY do not have "cinder" block. You have concrete block. Cinder block used to be made of the cinders that resulted from metal foundries.

 

[BillK]

If it is not moisture related you will probably have to get as much of the old paint off and then start from scratch with a good primer and paint. Had to do it one in an old warehouse. Big wire brushes and lots of elbow grease. That was a loooong time ago

 

[Stuart in MN]

What you may be seeing is not paint dust but efflorescence: https://en.wikipedia.org/wiki/Efflorescence Either way, you have moisture working its way through the wall from the exterior. It may be as simple as regrading the ground around your foundation so it slopes away, or it could be as difficult as having to dig down around the perimeter to install a moisture barrier and drain tile.

 

[brownbagg]

drvit

 

[BillK]

I don't know how any of you can say it is moisture without being there. The one I worked on was all above ground and just had 80 year old paint that was deteriorating.

 

[Stuart in MN]

I don't know how any of you can say it is moisture without being there. The one I worked on was all above ground and just had 80 year old paint that was deteriorating.

I think the key phrase in their post is 'constantly shedding'. If it's just old paint, once it flakes off it's done. If dust continues to appear, it's probably because of moisture.

 

[slim39]

You can get it at home Depot or Lowe's called drylock,. Used on the inside of my garage walls been dry for twenty years but they are above ground so I don't know if that will matter

 

[Bretny]

Anything you paint on over flaking off paint will just come off. You need to remove the old paint first.

 

[rburke65]

I have had good luck with the Drylok

 

[firebirdparts]

It sounds like efflourescence. I use UGL and it works fine. There is some better stuff out there. I had some rubberized paint put on but I don't recall the brand. I googled rubberized block sealant and found stuff, but I don't know what brand I actually have.

 

[58Yeoman]

It sounds like efflourescence. I use UGL and it works fine. There is some better stuff out there. I had some rubberized paint put on but I don't recall the brand. I googled rubberized block sealant and found stuff, but I don't know what brand I actually have.

^^This^^

I had this problem in my last house with concrete walls that was built in 1936. The concrete was crumbling, and the white fluffy stuff was always there. I tried painting it two different times with Drylock, and it still pushed the paint away. Google how to get rid of it.

 

[joes169]

You really only have two actual options here: Remove all of the old paint somehow (I've never seen a clean/affordable/easy way to do this in a basement) or dig up the exterior and WATERPROOF it from the positive side. Your foundation isn't much different than a boat below the water line, and concrete block are porous. As long as moisture is present on the exterior of the wall, it will wick it's way inward to the dry side. Paint WILL NOT stop water vapor from passing through.

Drylock is a waste of time, unless you're simply trying to the flip the house to the next unsuspecting chump. Bulk water and vapor will always win against paint, and slowly push the paint off of the wall, oftentimes taking some of the block with it.

 

[theoldwizard1]

You really only have two actual options here: Remove all of the old paint somehow (I've never seen a clean/affordable/easy way to do this in a basement)

Not clean and not easy, but my son removed all of the paint (multiple coats) from a basement cinder block wall using a 4" angle grinder and a half dozen HF cup brushes. Huge dust storm. Smoothest cinder block wall you ever saw after that. 2 coats of waterproofing paint (DryLok ?) and it looked almost like drywall,

 

[Bretny]

It may come down to the easiest and cleanest way to fix this is to just put up a wall over it if its really just pealing paint your dealing with.

 

[dg57]

You really only have two actual options here: Remove all of the old paint somehow (I've never seen a clean/affordable/easy way to do this in a basement) or dig up the exterior and WATERPROOF it from the positive side. Your foundation isn't much different than a boat below the water line, and concrete block are porous. As long as moisture is present on the exterior of the wall, it will wick it's way inward to the dry side. Paint WILL NOT stop water vapor from passing through.

Drylock is a waste of time, unless you're simply trying to the flip the house to the next unsuspecting chump. Bulk water and vapor will always win against paint, and slowly push the paint off of the wall, oftentimes taking some of the block with it.

One way to get a read on moisture issues is to tape a sheet of plastic to the wall. I would make sure all sides are sealed and do this during the wettest part of the year. If you see moisture accumulating behind the plastic, you have to fix the drainage. If no moisture likely a paint issue.