Split face block

[kurt]

The material is ubiquitous in Chicago. So are the moisture problems.

The current building has flashings & weeps, I'm still suspect, but that's another story.

The main story is trying to figure a way seal the block. A building next door has simply painted their block, and darnit, it seems to be working @ keeping out moisture.

How stupid could this be? Could the building breath to the interior satisfactorily to dissipate minor moisture?

I'm looking for general opinions.

[Bill Kibbel]

Originally posted by kurt

A building next door has simply painted their block, and darnit, it seems to be working @ keeping out moisture.

How stupid could this be?

100% acrylic latex over a Portland cement based building material is probably the least amount of stupid as compared to any other coatings.

Could the building breath to the interior satisfactorily to dissipate minor moisture?

It's probably working because it has just the right amount of water repelling ability combined with decent vapor permeability.

I wouldn't be the one to prescribe it as a guaranteed miracle cure, but it won't cause any harm (to Portland cement products).

[StevenT]

There is a company named Grailcoat. They manufacture synthetic stucco. It is water repelant yet breathes. It can be applied in many ways.

There are also silicone based products that are water repelant. They dry clear, although they will darken the finish.

[AHI in AR]

I had a one-man paint contracting business in the late'70's and early 80's during the summers when I was in school. One contract I got was to paint a new storage building at a cemetery which was split face block. Seems the GC didn't realize that concrete block weren't waterproof. They were even less so after the face had been split. Anyway, I found a product at a paint store which was designed for that application. It was a latex product with a cementitious component and was applied through my airless sprayer, but it was so abrasive that I ruined a tip on my gun each day. The orifice was about double the original size after a day's spraying. I assume it had fine sand in it to help plug pores.

It worked real well, though.

[kurt]

We're thinking Modac right now. 8.4 perm rating, cement paint coatings. We might change our mind, but now the research is on this stuff.

www.modacproducts.com

[chicago]

One site suggests they are mixing in a water repellent during manufacture.

What kind of problems are you seeing if they have the weeps and flashings in place.

Is it more of a moisture problem than the brick veneer in your opinion Kurt?

[kurt]

Originally posted by chicago

One site suggests they are mixing in a water repellent during manufacture.

What kind of problems are you seeing if they have the weeps and flashings in place.

Is it more of a moisture problem than the brick veneer in your opinion Kurt?

Water getting in all over the place. Much more problematic than brick veneer, because usually it's on a fully exposed wall, no overhangs.

It's always about the head joints & screwed up flashing.

[chicago]

Gottya,I have noticed they mix it in with the brick veneer for that castle look quite a bit lately.Grey stone retro.

[carle3]

I had a water intrusion problem that I swore up and down was from the split face. We tried sealing it with silicon concrete sealers and tinted latex block sealer with no luck. This is something I could not figure out until I caught wind that Semco was having some problems with their windows. Turns out they changed their window frame design. The design failed and was allowing water in through the mitered frame joints. Sealing for me did absolutely no good, just drove the moisture elsewhere.

[willlong]

The current solution seems to be a polyurethane based paing, sprayed on. Arrow masonry, which has been dealing with split block problems for 6 years, switched from silicone sealers to this, and it seem to work.

The only problem is that the building has to be dry to apply of you seal in the water.

I also recommend that the owners run a de-humidifier, full tilt boogie, for months.

Spray foam insulation is also preferred.

Hope this helps;

[kurt]

You talking Modac?

Harsh reality....... none of them "work". The Modac jobs are going south; maybe there's one that's working somewhere, but I've seen some Modac disasters.

I could take you to a couple spectacular failures that La Fletcha's (spanish for arrow) got on their roster.

The number of things that can, and do, go wrong with split face is almost endless.

[hausdok]

Modac? The genus of the carpenter ant - interesting.

ONE TEAM - ONE FIGHT!!!

Mike

[Jim Katen]

Modac? The genus of the carpenter ant - interesting.

ONE TEAM - ONE FIGHT!!!

Mike

I think they're Modoc - with an O.

- Jim Katen, Oregon

[esch]

Lime based water plaster sealed with shellac on INSIDE of block.

Thats the only thing I know

Matt

[kurt]

The "sealant" is on the inside.....(?)...... Shellac is a near perfect vapor barrier; it's going to hold all the water in the wall.

How do you imagine that works?

Even if you were going lime wash, you want it on the exterior, not the interior.

[esch]

Quote: Originally posted by kurt

The "sealant" is on the inside.....(?)...... Shellac is a near perfect vapor barrier; it's going to hold all the water in the wall.

How do you imagine that works?

Even if you were going lime wash, you want it on the exterior, not the interior.

It was kind of a joke, kind of not.

Never had moisture problem in the piney woods of East Texas with it. Sitting at 70% humidity on a dry day.

I dont know why we wouldnt have a problem with it and you would.

But I do know we troweled on plaster on the inside and shellaced it and the wall was dry as a bone on the inside.

Then again I dont know why this would affect it, but anything built with block was full of concrete 100%. There is no hollow block in my book.

Matt

Just thought I'd comment since I had forgotten all about that.

If you misunderstood, the plaster isnt a wash. Its applied with a hawk and trowel.

from 1/16 to 3/16 thick on the flat spots of the block.

[Raul Gonzalez]

You talking Modac?

Harsh reality....... none of them "work". The Modac jobs are going south; maybe there's one that's working somewhere, but I've seen some Modac disasters.

So if Modac is not the solution now, what's left for dealing with the water problems that are so ubiquitous in these split-face block buildings? Short of tearing down and rebuilding, that is.

[Scottpat]

You talking Modac?

Harsh reality....... none of them "work". The Modac jobs are going south; maybe there's one that's working somewhere, but I've seen some Modac disasters.

So if Modac is not the solution now, what's left for dealing with the water problems that are so ubiquitous in these split-face block buildings? Short of tearing down and rebuilding, that is.

A big tent! []

[kurt]

So if Modac is not the solution now, what's left for dealing with the water problems that are so ubiquitous in these split-face block buildings? Short of tearing down and rebuilding, that is.

That's the $250,000 question. I've seen Modac work, and I've seen it not work very, very badly. It held water in the wall, it didn't breath, and it's a total mess.

No silver bullet. They're all different, and some of them are really, really bad.

[Exterior]

We are working on bulding that was coated with Modac but the qualiti of labor was poor and the split face block was covered just about seventy % ,so its not always the material issue .We had done some jobs with Modac and as long it is applied as specified works perfect

[kurt]

That's the problem. Getting Modac applied to the correct thickness and coverage is almost impossible on split face block. Even with modac, so many of these dumps lack floor platform flashing, it doesn't matter. The water gets in anyway.

I found my first total failure 2 weeks ago. 7 year old building, and the top chord bearing floor truss' is totally rotten. Not just moldy and soft; rotted away, galvanize plates totally gone.

I think we'll see and hear about catastrophic failures on these suckers in a few years.

Milos, you remember me? I met you over on that siloxane job you did on Racine north of Belmont.

[willlong]

Well, it's started.

Did and inspection (maintenance) yesterday. Was called in by a contractor, but the owner and architect was there. 20 year old SFH with 3 stories and a penthouse in the middle of the roof with roof decks at front and back.The owner had bought the place 3 months ago (the poor guy).

Owner complained of possible water intrusion. Crown moulding was deformed. Did thermal and the roof joists were not normal. Protometer pegged out at the trusses.

The contractor open the ceiling and the trusses and roof deck were rotted (black, mold, sopping fiberglass insulation, no vapor barrier, the usual crap.

The only fix is to gut the top floor, replace the roof, trusses, etc.

Click to Enlarge

39.57 KB

Click to Enlarge

45.68 KB

[willlong]

I would add that the main structural problem is that the grout the trusses to the block. Pardon me if I am misinformed, but I was taught that wooden joists and trusses should never be in direct contact with masonry.

I fear structural failures with pancake collapses this winter, when the snow load occurs.

One other point. Who is the idiot who insists that there should be plastic sheeting behind the drywall? That just serves to create an aquafer.

Hope this helps;

[cve77]

My wife and I are looking at a short sale with extensive water damage to the drywall. A majority of the damage is on the eastern wall, which happens to be the only wall where split face block is utilized. I've been searching for "success stories" in remediating issues with the material, but am having a hard time finding any. I'm wondering if anyone here has heard of cases where the owners removed the wall and rebuilt? Or is this just completely crazy?

[kurt]

Yes, that's fairly crazy.

There's better stuff to do.