Mark Meshulam is an expert witness and consultant for split face block leaks.
Being market driven, your Chicago Window Expert has been driven into the world of masonry by Chicagoans driven to distraction by leaks driven through split face block walls. Is this onomatopoeia? Sadly, no.

splitfaceblock

What is split face block?

Split face block is a variation of concrete block, otherwise known as CMU (cement masonry units) or even “cinder block”. The split-face variety has an irregular exterior face designed to look like chiseled stone, and the effect works. Split face has a warm appearance that is far more attractive than flat concrete block. In fact, if I was blind, I would say it looks exactly like chiseled stone.

An inexpensive alternative

For this reason, literally hundreds of developers in the past 20 years chose split face block as their exterior wall material for the sides and backs of 3 flats, 6 flats and other multi-unit residential buildings. They generally used higher quality glazed brick on the front of the buildings, resulting in fewer leaks there. But the split face block leak! So we should blame the block, right?

We utilized a spray rack on a masonry corner that is known to leak, in order to view the leaks on the interior
We utilized a spray rack on a masonry corner that is known to leak, in order to view the leaks on the interior We utilized a spray rack on a masonry corner that is known to leak, in order to view the leaks on the interior
Fifteen minutes into the spray rack test, these leaks appeared on the interior of the split face block.
Fifteen minutes into the spray rack test, these leaks appeared on the interior of the split face block. Fifteen minutes into the spray rack test, these leaks appeared on the interior of the split face block.
Split face and concrete block leaking in corner after 1/2 hour of water spray
Split face and concrete block leaking in corner after 1/2 hour of water spray Split face and concrete block leaking in corner after 1/2 hour of water spray
This mason knows what he is doing. Through-wall flashing in block backup wall is a few courses above the lintel location. Tiebacks are seen dotting the face of the block.
This mason knows what he is doing. Through-wall flashing in block backup wall is a few courses above the lintel location. Tiebacks are seen dotting the face of the block. This mason knows what he is doing. Through-wall flashing in block backup wall is a few courses above the lintel location. Tiebacks are seen dotting the face of the block.

Don’t blame the block

Not so fast. It’s easy to trash split face block as a “bad” material and to condemn the developers as greedy and evil. That is an amusing pastime in many HOAs. But from what I am seeing, these developers tried to put together a decent product. They often used nice exterior design and decent interior finishes.

Ignorance of good design

Unfortunately, they appear to be ignorant of certain simple facts of construction. And if they are ignorant, maybe it is actually their architects who are to blame.

Galvanized wire tiebacks are bedded in mortar joints so that the little loops project out, available for hooks coming from the face brick, to engage.
Galvanized wire tiebacks are bedded in mortar joints so that the little loops project out, available for hooks coming from the face brick, to engage. Galvanized wire tiebacks are bedded in mortar joints so that the little loops project out, available for hooks coming from the face brick, to engage.


Whomever deserves blame for the split face block leak fiasco, the unfortunate current owners are left holding the soggy bag.

Testing split face block leaks

Having been called to many buildings with split face block leaks, I found a few where the leaking was so bad that the interior drywall had to be removed. This afforded me a rare glimpse of the interior side of a leaking split face block wall, wetting in real time.

Bituminous waterproofing is sprayed on the face of the block backup wall prior to installation of the face brick. Yes!
Bituminous waterproofing is sprayed on the face of the block backup wall prior to installation of the face brick. Yes! Bituminous waterproofing is sprayed on the face of the block backup wall prior to installation of the face brick. Yes!

With the use of a spray rack, I was able to induce active leaks in just a few minutes. Check out the pictures at the right and the video below for some fairly shocking imagery. This could be happening inside your walls!

The finished product is not only attractive, but it .will provide many years of leakproof use. It's all in what's behind.
The finished product is not only attractive, but it .will provide many years of leakproof use. It's all in what's behind.  The finished product is not only attractive, but it .will provide many years of leakproof use. It\’s all the design.

Design concepts to remember

Here are the facts that were ignored, leading us to believe that split face block leaks just because it is bad:

  1. All masonry leaks. Split face block just leaks more. It’s more porous.
  2. Newer masonry leaks more than older masonry. This is because older masonry is generally more massive. In the old days, masonry was used to actually hold up the building (the Monadnock Building has structural masonry walls 8 feet thick at the base). A smaller older building may easily have three or more wythes (thicknesses) of brick. The sad building we sprayed in the video had only one wythe of hollow split face block and the leaks appeared on the inside of the block quickly.
  3. As our buildings evolved, masonry became an ornament, not structural. Other stuff, like steel studs, were needed to hold it up. Yet other stuff was needed to make it waterproof.
  4. We began to utilize masonry cavity walls, sometimes called masonry veneer walls. In this scheme, an inner wall of concrete block or studs with sheathing, is built. Then the masonry veneer wall is built to the outside of the inner wall with an airspace between the two. Intermittent connecters tie the two layers to one another for stability. The outside of the inner wall is waterproofed, so that water that penetrates the face brick will simply drain down to the bottom, where metal or rubber flashings direct the water outside.
  5. Then some brilliant, cost cutting builder thought, “Who needs the waterproofing?” And that started the moist, slippery path we see today.
  6. Because the next brilliant, cost cutting builder thought, “Who needs the back-up wall?”
  7. And then the next brilliant, cost cutting builder thought, “Who needs a glaze on the brick?
  8. And then the next brilliant, cost cutting builder thought, “Who needs brick (a dense clay mixture fired in a furnace) at all? Why not just use lightweight, hollow concrete block instead?

Masonry’s fall from grace

And thus the once-proud masonry wall (there is even a society that uses the surpassing strength and mystical beauty of masonry as a metaphor for the way one should live one’s life – ever hear of the Masons? Illinois Masonic Hospital?) has been cheapened by degrees so that it doesn’t even hold itself up any more, let alone keep out the rain.

And so, dear reader, if you plan to involve yourself with this wonderful, yet shamefully degraded material, please understand that it needs some TLC in order to do its job. Make sure your wall has these design features to avoid split face block leaks:

  • Masonry (including split face block) needs a waterproof barrier behind it and an airspace to allow water to drain.
  • Masonry needs tiebacks that connect it to structure behind it, yet these tiebacks must not violate the water barrier.
  • Masonry needs metal or rubberized flashings at the bottom of all parts of the wall, to capture water and direct it to the outside.
  • Masonry needs weeps or openings in the masonry to allow water accumulated on the flashings to flow outside. You can get masonry leaks, including split face block leaks if the drainage path is obstructed with mortar droppings in the wall cavity.
  • Masonry needs decently mixed and applied mortar joints, to keep the amount of water penetrating the wall to a minimum.
  • Masonry needs a glaze, coating or inherent water repellant to reduce the amount of water entering the wall.

If you are saddled with split face block leaks, fear less, because help is on the way. Your ChicagoWindow Expert has consulted with some of the top providers of solutions, and we have some that will work right now.
Examples of masonry wall design from the Masonry Advisory Council

Mark Meshulam, Chicago Window Expert, discovers that masonry leaks too!
Mark Meshulam, Chicago Window Expert, discovers that masonry leaks too! Mark Meshulam, Chicago Window Expert, discovers that masonry leaks too!


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8 thoughts on “Split Face Block Leaks”

  1. Interesting article however being a mason I have to point out a few things, I wouldn’t say that all masonry leaks I would state that all untreated masonry is porous. If constructed properly, following all specifications and details a masonry wall should not leak, it will however take in water, but if properly constructed by a skilled and knowledgeable mason who uses proper flashing at the base of the wall as well at all door and window openings, proper waterproofing/damp proofing at the cavity wall ( Tyvek with taped seams if veneer only), weep vents, along with properly tooled mortar joints, the moisture which enters the wall will escape in a controlled manner as it is designed to do. But, if improper materials, improper mortar, cheap flashing, improper technique during flashing installation and most importantly an unskilled labor force is used than your masonry will leak. Being a mason I personally believe that many of the problems associated with the leaky walls could have been avoided if plans and specification were followed by both the mason and the general contractor.

  2. I am a leading forensic architect in Chicago. I find the comment in your article “Unfortunately, they (masons) appear to be ignorant of certain simple facts of construction. And if they are ignorant, maybe it is actually their architects who are to blame.” to be ignorant. Architects are not responsible for the education of tradesmen nor are they responsible for construction means and methods or the quality of construction unless it is stated in an Owner/Contractor agreement. It’s obvious you are not an experienced architect or construction attorney and that makes you unqualified to dictate what an architect is responsible for.

    Roger E. Medema
    Illinois Licensed Architect
    #001.011654

  3. Robert,

    I would not expect an architect to stand on a scaffold and show a mason how to lay brick. When I used the word “they”, I was referring to the developer, or owner of the project.

    I would expect an architect to specify a masonry design that contains all the elements needed for successful construction. If the owner is trying to save money and eliminate one of the essential elements, I would expect the architect to teach the owner that the wall will leak if essential elements are omitted.

    Do you agree?

  4. As a Certified Consultant of Concrete Masonry, I can tell you that the leaks are coming from the mortar joints.
    There are many other flaws in your article that I would be more than happy to point out, if you would like, when I have more time.

  5. Mark and to all Others responding to this:
    I have to agree with what is stated from above statements posted. I would add as well you seem to have been around enough projects to know if a installation process of the block walls where performed by specs or not. I also have to say that you know that at any time the Client(s) of a project decides to changes to their project they would be able to as long as it still meets the building code requirements. As to the Architect and what they are in charge of doing is or has nothing to do with what is being asked about. All the Architect has to do is to make sure that the build is being built as to the drawings submitted with whatever change orders was provided. It is not the Architect’s job to train trades people. It is the Project Manager along with Building Contractor to make sure that the job is supplied with skill trades personal.
    As stated before, I have never had issues like you are or have faced in the pics that I have viewed. To me, you have had unskilled workers performing on those projects and the contractor should be held accountable for their instullation of product.
    Another thing that has my light bulb on was you stated that there was no grout or rebar installed in core of the block. Anyone knows when deal with load bearing walls that are of any type of block it needs to have rebar and grout installed every 24″ to 32″ for strength.
    well I will get off my band wagon for now! Way to much to talk about with these issues! I will keep reading and post as we go along!

  6. Treating the leaks on your walls is not an easy job. We have to ask for the help of professionals. But hat you have pointed out is a great help for I am living in an apartment. I may say that this is a good tip for I can ask my landlady for the help to check the walls. This is for the benefit of everybody. Thanks.

  7. Some of the posts went from the original post of splitface block to structural block which is a more detailed installation and elude the actual fix or preventative action of splitface block in the original building process. Splitface block now days can be used as an Architectural enhancement to a building where structure of block is not needed, then simply framed and sheetrocked on the inside. Some splitface are not Architectural but structural but the same purpose applies. You still need rebar and concrete reinforcement, either way splitface block are the exterior. Typically regular exterior block are painted and waterproofing is not necessary. We here use what is called “Dryblok” which is a waterproofing admixure actually placed in the splitface block at the time it’s manufactured… “if called for in the plans”. Then the same mix is placed into the mortar at the time of installation which waterproofs the joints…therefore the entire splitface block and joint are repelling water at the same time protecting your investment in the building. That fact if neglected during the planning stage is not a blame put on the mason unless ignored but the designer of the project. That is money figured into the bid and not an extra. To me this is important in the design of a struture and if not included in the Spec book from the conception of the project it is destined to fail. I am a mason and have a masonry repair business and I find that simple waterproofing saves the life of all masonry from brick to stone if started early in the game.

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