Split block problems - how widespread? (Chicago, Metropolis: hardwood floors, countertops, condos)

[Chi-town Native]

OK, so I hit this story again:

City Room™ - Metro - Moldy Metropolis: Homeowners Struggle with Leaky Concrete

And was blown away by the comments. I am more than a little concerned that in 10 - 20 years we are going to have a sea of ghettoized housing all over the place, as it doesn't sound like you can really fix these buildings if they weren't sealed properly to begin with.

[Irishtom29]

I imagine many buyers were more concerned their new condos had HGTV's Holy Trinity----hardwood floors, granite countertops and stainless appliances. Now they learn.

[Intergalactic]

I always thought those cinderblock constructs looked shoddy.

[chet everett]

Duh.

Concrete blocks are porous, so porous that a well known water-proofing coating company has displays in hardware stores that actually use an aquarium pump to show how water flows right through the uncoated block.

Vast majority of the installations of the concrete block are NOT following all the steps of isolation of exterior wall from the interior and that leads to BAD moisture problems. Hard to completely fix too, as some of the flaws are in the roofing install too.

It will be Chicago's versions EIFS...

[jcarlilesiu]

You don't want to seal masonry in the first place. Condensation building on the inside of the walls from changes in temperature needs to be able to escape and most buildings using split face block are new enough to have systems installed to allow the moisture out.

The problem with all masonry is that it is extremely pourous and thus allows water to soak into it. Clay fired brick masonry more commonly used in the past does the same thing. Ever see a new construction where the brick turned all white. That is called efflourescence and is caused by the moisture coming to the exterior brick and bringing with it the natural mineral and salt deposits inside the brick. Flat faced or flush CMU block will do the same thing, but if you ever rubbed your hand against it, its rather smooth.

Split face block on the other hand is split after the concrete cures allowing millions of little bug holes and a whole lot of places for water to enter the masonry. Many times, CMU block, specifically split face block is used not as a veneer on the outside of a building like many brick masonry construction techniques, and rather furring strips and drywall are attached at the interior. This is a problem because once the water gets in behind the wall, there is no where for it to go, or get out, thus causing mold. There are cases where the block is used with a cavity space which allows moisture back out through a flashing and weep system. Typically this construction method also has a good moisture protection system installed to prevent water from entering the building from the cavity in the wall. Thus, not all buildings with this type of construction are affected.

Even though you aren't supposed to seal masonry, if you live in a building with furing directly applied to the block, I would suggest a good quality sealer product made for this installation. Painting the block is always an option as well.

With any product of this nature, routine maintanence and upkeep of the sealer system is necessary.

[Lookout Kid]

CMU should never be used as an exterior wall surface. A proper masonry wall has 8" CMU with a four inch cavity before the face brick (which is tied to the CMU backup with masonry ties). It is within that cavity that you put 2" rigid insulation and an air and water barrier. It is flashed at the bottom with weep holes to allow drainage of the cavity.

"Sealing" CMU as an exterior wall solution is terrible, and should have never been allowed by the city. But you certainly see it all over the place in Chicago. A lot of these new construction low-rise condo buildings will cause trouble for the owners for decades to come because they were never built properly.

[CptnRn]

As an architect I find this appalling. Cinder block buildings can be fine structures if properly designed and constructed.

This whole building construction process was badly flawed, from design thru execution. The city should be requiring that the building designs be prepared and sealed by licensed architects and engineers, who then inspect the construction at appropriate intervals to verify that the building designs are being executed correctly by the contractors.

In the states that I have worked in, building inspectors are typically not expected to take responsibility for the entire design and execution and are seldom trained or educated sufficiently to do so. They typically target only specific limited permit issues like electrical and plumbing. However with such a flawed building permitting and inspections system, I do believe they are responsible for failure to protect the public.

Anyone with a minimal amount of training in masonry construction knows you can't count on a single width of masonry to be waterproof, not even brick. The veneer exposed to the weather will weep moisture, it absolutely has to be backed up with a water proof cavity with proper flashing where the moisture can run down to weep holes and get out of the wall.

See examples here Masonry wall systems, details

One should never rely on a so called "waterproof" coating on the exterior to keep the wall waterproof. They all deteriorate from UV exposure and expansion contraction of the wall, and eventually fail.

Whoever designed these buildings should be sued.