cinder block problem - Contractor Talk - Professional Construction and Remodeling Forum

RCPainting · 07-28-2006, 08:59 PM

There is a apt. housing complex I occasionly paint at. Picture a strip of apts, all made of cinder block, even the interior walls. They do not go all the way to the cieling. There are no doors and the floors are linoleum. The interior walls on the north side always have mold growing. On the outside there is grass with sprinklers that hit the wall. I do not think there is any type of insulation in the brick. What do you suggest I use to seal the block. I have tried mold inhibitors. This is a migrant type of housing. There is a lot of turnover and often there are many people living in a 2 bedroom/1 bath. There is no ventilation.Thanks!

ATS · 07-28-2006, 09:08 PM

I'm no painter but dang-it, they ain't cinder blocks, they are CMU's. Get it right!

Richard · 07-28-2006, 09:52 PM

Assuming the surface is clean and dry, you could use SW's Preprite SF-1...I've had real good luck with this product. This is for any interior sealing. For the exterior I would use SW's Loxon, no questions asked. These are primers...you can use a variety of paints for the finish, I usually use SW's Superpaint inside and SW's A-100 outside.

Whatever you do, please use quality products...they will last through the "abuse" your talking about much longer than wanna-be-products!

Jonesey · 07-28-2006, 10:07 PM

Had this probelm when I was doing dorms for the university. Could never find anything that would work well for more than a year. We just scraped it, killed the fluffy mold with bleach and reprimed and painted.

It's a humidity problem, not really a finish problem. Best bet is to install modern AC systems.

There are additives you can use, but they don't work very well. If it's what I'm thinking of, it's actually a fungus that feeds off the minerals in the block itself.

If anybody has any ideas, I'd love to hear them. Have tried about everything.

Woz the Painter · 07-29-2006, 12:04 AM

Quote:

Originally Posted by ATS

I'm no painter but dang-it, they ain't cinder blocks, they are CMU's. Get it right!

CMU's are nothiong but a term given to a product by architects who think their ***** don't stink...

Brushslingers · 07-29-2006, 08:12 AM

North side where the sun doesn't hit, ground prolly slopes slightly to the east or west. It's a fairly common problem in brick or block construction when the material is slightly (or alot) underground. You would have to start outside, dig down to the bottom all the way along the structure, and apply a tar waterproofing from the bottom to about 1 foot above the ground. Nice and thick. Dry out the inside real well with de-humidifiers and find the moisture. You said the block doesn't go all the way to the ceiling.. is it drywall? You may have some moisture soaked insulation, something between the blocks that a careless worker tossed in, slight roof flashing leakage, etc. Good luck.

RCPainting · 07-30-2006, 10:44 AM

Thanks for your help!
The interior walls do not go all the way up. There is no insulation, drywall, other materials. Just concrete/cinder blocks and vinyl floors.
Highly unlikely owners will pay to dig up and watrproof. I will try the SW products mention. Again, Thanks to all!
OK, Ill bite, what is a cmu?

lmcgrew79 · 07-30-2006, 09:20 PM

UGL, XIM, or Loxon would be fine. SW makes a good product called sherlastic for exterior substrates its impermiable where as regular 100 acrylic paint is permiable. Great for CONCRETE MASONRY UNITS

Brushslingers · 07-30-2006, 11:17 PM

Still missing something, the interior walls do not go all the way up. Whats between the ceiling and the walls? The only way mold grows is moisture, period. I have used an oil lamp wick to track down WHERE the moisture is coming from, tack it above and below the mold, and the ceiling... using a moisture tester you can tell within a week where the moisture is but... your missing something. Ceilings have insulation even. Loxon is a good product but, just like oil over latex... any latex over water will NOT work for long.

RCPainting · 07-31-2006, 06:57 AM

The interior walls of each unit have a gap of 12" between top of wall and cieling. I think part of the problem is there is the moisture from the bath and kitchen permeates the whole unit. That and the northside exterior wall being watered in the summer and covered in snow during the winter. I'll try the mentioned products. Thanks

Zack · 08-09-2006, 10:09 AM

Seal the brick with a antimicrobial and then run metal channel so that air can get through. This will prevent humidity and keep mold from growing.