Solving the Split Faced Blockproblem.| Decker Home InspectionServices.Masonry Building Problems in Chicago.

Many newer masonry buildings in Chicago suffer from "wet-buildingsyndrome".

By William Decker, CMI

What is Split Faced Block and why was it used:

Since the mid 1990s, especiallyduring the building boom of the earlyto mid 2000's, there were many newcondominium buildings constructedin the Chicago area. Many of thesecondominium buildings utilized anewer exterior masonry product thatis commonly called split facedconcrete block. This material lookedlike an 8" thick common "cinder block", but had a rough face, making it looklike stone (Right). The material is manufactured using aggregate, Portlandcement and course sand. During manufacture, a complete 16" block is"split" in two so as form two 8" thick blocks, each with a rough face alongthe split edge. The finished product resembles rock-faced masonry inRichardsonian Romanesque houses popular in the mid-1880s (below). But,as we shall see, prioritizing form over function can lead to long termproblems when building houses.

Split faced block wascommonly used as theexterior wall cladding onthe sides and rear of 3, 6and 8 unit condominiumbuildings and some singlefamily houses with thefront of the buildings,usually, being coveredwith brick or stone. "Wasused" is the operative

phrase because using this material in new construction residential buildingshas, largely, been stopped in the Chicago area, in late 2009.

Split faced block was chosen by builders for a number of reasons, but thebiggest one was cost. Here are the cost factors:

- Split faced block material costs are low.

- Being larger than a brick, it is quicker to lay and faster to install.

- This block is strong enough to use as a structural wall (i.e. a wall thatactually supports the building) and attractive enough to use as an exteriorcladding wall at the same time (this is, technically, what is called a singlewythe wall, a wall that is only one layer of masonry thick).

- The material could be installed by less expensive, sometimes newlyimmigrated, non-union masons.

Problems and Causes:

The problems seen with many split faced block buildings have been theresult of water intrusion. The symptoms include water stains and bubblingpaint on ceilings and walls, warping and buckling hardwood floors, water

dripping from exterior wall outlets and light switch boxes, musty smells andmold formation. In extreme cases of long term water intrusion, the roof andfloor joist ends get wet and rot. This can lead to catastrophic structuralcollapse, where roofs and floors collapse! It is important to realize thatthese are not the problems, they are merely the symptoms of the realproblem which is water intrusion into and through the block. Many times,home owners will have the roof replaced or "fixed". When water is comingthrough your ceiling or walls near the ceiling, people logically thing that theroof is leaking. I have many clients who had their roofs completelyreplaced, but the water kept coming in. The best solution is always to solvethe primary issue (the water intrusion) before addressing the secondarysymptoms.

PLEASE NOTE: Many fly-by-night predators (and even some reputablemasonry companies), seeking a quick fix and a quick buck, are goingaround promoting "sealing" the exterior of the block as the "easy fix". Whileusing water proof block or applying an exterior sealer may help in somecases, the block not being sealed is NOT the primary problem with thesebuildings. It is only one factor, and a minor factor at that. In my research Ihave found that only 8 - 11% of the water entering the building is coming inthrough the block, laterally. There are many split block buildings that havenever been sealed but have also never had water intrusion problems. Eachbuilding is different in its construction and each building has to be evaluatedbased upon its individual construction details. Quick fixes offered by theproverbial "two guys in white panel van" cost you money and time but donot fix the problem.

Why does the water come in?

To fully understand why split faced block houses and buildings have waterproblems, it is first necessary to understand how these buildings were built. The first thing to understand is that all masonry is porous and absorbswater. Brick, stone, cinder block and split faced block will all absorb water.

So why aren't all the old brick and stone houses having water problems? The reason is that they were built with multiple wythe walls. Multiple wythe(width) walls are actually two (and sometimes three or four) walls in one. The inner one or two widths are structural and support the building'sweight, while the outer wall (sometimes called a veneer wall) does not. Between the inner and outer walls is an air gap, usually about 1" wide. Water will travel in pretty much any direction, based upon gravity, pressuredifferences, humidity, capillary action and heat gradients, but the one thingthat water will not cross is an air gap. This is the biggest issue with splitfaced block buildings. They were, almost always, built without an air gap asa single wythe walls.

Even when built in thesingle wytheconfiguration, split facedblock buildings canavoid water intrusionproblems if they areproperly designed andbuilt. Looking at thediagram to the left, wesee how a split facedblock wall should bebuilt, based uponbuilding science bestpractices and industrystandard specifications. But these details arerarely used.

Coping flashing - The top of the exterior walls (also called the parapet)must be properly sealed. The top of the wall is usually covered with a pieceof stone. This stone is supposed to keep rain water from entering the top of

the wall and seeping through the masonry. Think of an umbrella. Manymasons are not aware that this stone, itself, is porous and, given time,moisture will still get through. Older buildings were constructed usinglimestone that was 3 - 4" thick and would dry out faster than the rain madeit wet. The newer product (which is much less expensive) is a smallaggregate concrete block that is polished to resemble limestone(Renaissance stone) and is usually 1 3/4 - 2" thick. It is also very porous towater.

Best practices call for the installation of a non-porous membrane of rubberor metal (called flashing) over the entire width of wall and under the copingstone. This serves as a barrier to water intrusion. This construction detail iscrucial because the majority (70 - 80%) of the intruding water enters the wallthrough the coping stone.

Parapet wall ventilation - While the top of the parapet wall should becovered and sealed to keep water from entering the top of the wall, the wallitself should also be ventilated. This is a classic construction technique thathas been used for hundreds of years but seems to be lost to most modernArchitects and Builders.

The blocks themselves have air cells inside (left). If these internal cells areallowed to ventilate to the outside (above), to "breath", moisture that is inthe wall will be able to evaporate and be less inclined to pass through to theinterior. This is was done in the older brick buildings in Chicago, where theparapet wall was "capped" with clay coping tiles and many of thesebuildings are over 80 years old and still in good condition. The inside and

outside edges of thesetiles provided an air spacethat allowed the interior ofthe brick walls to breath.

Mortar and block cracks- Another concern iscracking of the mortar. Intuitively, we think that bigcracks in the mortarbetween the block will

allow more water to enter the wall. In fact, the opposite is true. Big cracksdo allow waster to enter, but they also allow this same water to drain out. Small, hairline cracks are much more of a problem. They do not just "allow"water to enter the crack, that actually suck it in through a process calledcapillary action. Because the crack is so narrow, the surface tension of thewater draws rain into the crack where it is soon absorbed by the blocksnatural porosity. Another problem with the mortar is caused by theemployment of masons who do not understand the local conditions. Manynewly immigrated masons have a long tradition, "from the old country" toadd extra sand to the already pre-mixed mortar. They believe that this willmake the mortar stronger, when it also makes the mortar more waterabsorbent. Both these factors lead to water being absorbed into the block.

Flashing - When building a house, all areas that can possibly allow water toenter the building should be, so to speak, waterproofed. The problem isthat almost impossible because most building materials (wood, stone,masonry, siding) are porous. The exterior of a building is not "waterproof"but merely water resistant. It allows waster to "shed" off the exteriorsurface. These susceptible areas must be "flashed". Flashing involvesinstalling a water impermeable barrier (vinyl, rubber or metal) between theoutside and the inside of the house, and between building materials ofdifferent water absorptive levels (i.e., between wood and masonry).

Flashingmaterials donot allowwater (orwater vapor)to passthrough themand act todrainageplane tofurther shed

any moisture absorbed in the wall down and out. This is why some betterbuilt properties have the flashing, along with small pieces or rope (weepwicks, left) sticking out of the side walls at the level of the floor joists.

BTW: Home Inspection Rule # 101: "Caulking is NOT flashing!". Caulk willcrack, come loose and deteriorate. Any opening that is caulked (windowand door frames, roof penetrations, bathtub / tile corners) must also haveflashing of some sort behind the caulk. Caulk alone will not stop water and,in most cases, is more cosmetic than functional. Many times, in an effort to"fix" water intrusion problems, inexperienced workers will caulk an openingthat should be left open to allow for water drainage. This is commonly seenabove windows and doors where the drainage space between the steellintel and the block / brick is caulked or mortared shut. Rather than stopwater from entering the wall, it blocks the designed drainage opening andcauses water to back up and drain down from the top if the windows anddoors on the inside.

Joist flashing - The floors and roof of these buildings are supported byfloor and roof joists. Commonly, these joists are engineered woodentrusses, specially designed and manufactured assemblies that are muchstronger than a normal solid piece of lumber. They are usually constructedof lengths of 2 x 4 lumber secured with metal plates called gussets. These

truss joists areinserted into pocketsin the block masonrywalls. There shouldalso be a flashingmembrane installedbetween the blockand the woodentrusses to keep wateraway from the wood. The truss should alsobe installed withsupporting shims andthere should be an airgap between thetruss's wood and themasonry. Themembrane and theair gap both provideprotection againstwater wicking into the truss. It is never a good idea for wood to get wet orbe in contact with masonry. Problems occur when the builders, a) do notinstall the flashing properly and / or, b) grout the truss end pocket instead ofshimming. In both cases, moisture from the masonry wicks into thewooden truss ends, rotting the wood and rusting the securing gussets. Aswe shall see, later, this can lead to a very serious problem.

Exterior wall flashing - The other reason for the joist flashing is to catchany moisture that is draining down, within the wall, and direct it outward,away from the building. This flashing membrane should be upturned on theinterior side of the wall (so as to catch and drain the water outward) andextend out of the exterior side of the wall, forming a drip edge. The dripedge should extend, at least, 5/8" away from the wall. Current national

construction standards call for the exterior drip edges to be made ofstainless steel or copper, for durability.

Many times, the masons (or the insulation sub-contractors) do not properlyturn up the interior end of the flashing and this allows water to drain into thebuilding, warping hardwood floors and causing tiles to crack. Similarly,many builders fail to properly extend the exterior drip edge far enoughoutward from the exterior of the wall which allows the water (both already inthe wall and water falling on the wall) to be sucked back into the masonrymortar. It is am ironic circumstance that many builders do not install thisflashing because the buyers will think it looks "ugly". Functionality shouldalways trump any cosmetics of a building and they should be designed tobe properly appealing in the first place.

Solutions:

Exterior wall sealing - Contrary to common believe, sealing the block isNOT the final solution, but does help (BUT DOES NOT CURE) the problem. While it is better to have the block sealed, it is not necessary if the buildingwas properly constructed. Sealing adds water impermeability to the blockand acts to shed water off the surface. When the exterior wall of block isnot sealed, and depending upon local weather conditions, rain water and

humidity in the air is drawn into the block. This moisture travels through themasonry into the insulation and drywall. It should be stressed that themajority (70 - 80%) of the water intrusion DOES NOT come, from the sides,through the walls but flows downwards from the unflashed parapet wallcoping stones and stone window sills. That being said, the moistureintrusion through the walls must not be ignored.

A curious phenomenon that we have observed, many times, is what isknown as "solar loading". Imagine a large building with split faced blocksides and the south and / or west sides exposed to the sun. It rains for acouple of days, not a hard driving rain but just a steady drizzle. There areno water intrusion problems while it is raining. Finally, the rain stops and thesun comes out. After 4 to 6 hours (around 1:00 PM or so) water startsstaining the interior wall and dripping through electrical outlet and lightswitch covers on the south side. One wonders why the water didn't comein during the rain, but does when the sun is shining.

What is happening is that the sun is heating the exterior block wall. Intuitively, one thinks that the sun will dry the water. In reality, the sun isonly "drying" the moisture on the very surface of the block. The rest of thewater that has already been absorbed is actually being driven further intothe masonry because the heat of the sun is expanding its volume,increasing the vapor pressure and further pushing the water that wasalready in the masonry out into the insulation, drywall and out the wall. Thiscondition is exacerbated by the the use of mid-efficiency forced air furnacesin many of these condominium units which draws a significant volume of airout of the building. The negative interior air pressure works to actually suckthe water in through the block.

It is interesting to note and contrary to common sense that masonrybuildings, in fact, do most of their drying out during the winter, not thesummer. In the winter, heat moves outward from the heated interior livingspace. As this heat moves, it pushes any moisture in the masonry ahead of

it (heated water expands). When this water reaches the exterior surface ofthe masonry, the cold, dry air causes it to evaporate. This sometimes leavesa white, fluffy powder on the outside of the wall. This is called efflorescenceand is the result of the outgoing water dissolving some of the lime in thewall mortar. The water dries on the outside of the wall and leaves the lime. Because of a couple of relatively warm (and wet) winters in our area,problems with water intrusion in masonry has been much more pronounced.

The old, commonly accepted best practices method of split faced blocksealing used to be applying a "pigmented, silicone based, silane/siloxane,penetrating sealer", but it has been found that such products only lasted 3to 5 years (depending upon the manufacturer and the skill of application). Many times, the sealing contractor has not been properly trained in how toapply the sealer, and the condition of many "sealed" buildings attests to thisfact. Silicone silane/siloxane sealers MUST be applied in a flood coat,completely covering the block and allowed to be soaked into the block. Repeated sealing is also expensive, Properly sealing a 3 storycondominium building is expensive ($17,000 - 21,000, professionally done). The current preferred sealing solution is a polyurethane or elastomericbased "plugger" type paint, installed by licensed, insured, trained andqualified masonry contractors. This product will completely seal both theblock and any small cracks in the mortar joints rather than just retardabsorption and can last for 10 - 15 years. But, this solution does not solvethe larger problem and will NOT guarantee that the building will stay dry.

Drying out the retained moisture - When a split faced block wall has beenexposed to moisture for a long time, it tends to retain (or "sequester") thewater deep in the block. Think of a wide sponge. If you spray it with waterit will absorb the water. When the sponge's capacity to absorb the water isexceeded (in building science, this is called the "hygric buffer barrier") waterwill start leaking out the other side. But, the water being leaked is NOT thesame water that is being sprayed on the other side. There is always goingto be some water, "in the pipeline", so to speak. Split faced block can

absorb its own weight in water, and this retained water has to be removed.

Once theexterior wallsand parapethave beenproperlyflashed andsealed, nomore waterwill enter thewall. BUT,there is still a

great deal of water that is already in the wall, and will not dry out becausethe exterior has been sealed against water getting in, and water getting out.

To fully solve theproblem, the waterthat has alreadybeen absorbed inthe masonry has tobe removed. Thiscan only be doneby greatly loweringthe humidity levelsinside the house,which will draw the water out of the masonry through the insulation anddrywall. Remember, in a typical three unit, duplex down, condominiumbuilding with split faced block on the sides and rear, there is approximately2,500 GALLONS of water that is still in the block.

This process requires time (3 to 4 weeks, depending upon the conditions)and multiple, industrial capacity de-humidifiers running, full tilt and 24/7,

under closed building protocols. This requires that the doors and windowsin the house or building be kept closed (except for normal entering andexiting). Many times, we have seen home and condominium owners whobelieve that once the cause of the water intrusion has been solved, they canjust re-drywall and / or re-paint and everything will be fine. They soon findthe same water stains reappearing, sometimes in less than a week. Solvethe cause of the problem, then remove all the residual moisture beforetending to the cosmetic details. A car may have a really shiny and smoothpaint job and cool chrome, but what really counts is what is under the hood.

Final steps - OK, we have solved the source of the water intrusion, and wehave dried out the masonry walls. Now we can "fix" the original problemsthat were the first complaint (i.e., water stains, puddles, mold growth, a"musty" smell, warped window frames, baseboards and window frames,etc). Fine!

But how do we repair these problems, and do so following "bestconstruction practices" (i.e., what the original builder should have done it inthe first place!).

First, make sure that you have properly (and professionally) remediated anymold problems. Mold, growing on porous surfaces like drywall and wood ISNOT KILLED! IT HAS TO BE REMOVED! Many people want to minimizethe amount of repair needed and believe that they will just "kill" the moldand paint over it. MOLD IS NOT KILLED, IT HAS TO BE REMOVED! All theaffected building materials (drywall, wood, insulation, wallpaper, etc) mustbe removed (torn out). What cannot be removed (wall studs, structuralmembers) must be professionally treated and encapsulated. This is NOT ajob to be done on the cheap or by non-qualified workman. To do otherwiseis to be inviting the mold to come back again. Make sure that any moldremediation is done by specifically trained and certified workers!

DO NOT USE BLEACH TO CLEAN MOLD! It will only make it worse. Moldon tile, grout and other non-porous surfaces can be killed with bleach, but

for porous surfaces (i.e., drywall, wood, insulation) you must use specialmeans. A good, over the counter product is Mold Control which is availableat most home improvement stores and many people believe that they cansave money by doing it themselves. The best solution is to hire aprofessional, licensed, certified and insured mold remediation company. There are plenty of guys out there who claim that they can clean mold, butyou should always ask to see their credentials, licenses and insurance coversheets and ask if they utilize a licensed industrial hygienist when makingtheir remediation plans. Also ask about their guarantee. There is no statelicensing or government required qualification requirements for moldremediation contractors. Also make sure that, after the work is done, youhave a "clearance test" done by an independent mold testing inspector. Clearance testing is the only way to make sure that the mold problem hasbeen properly completed. Reputable mold remediation companies willcome back and fix any problem, usually for free, if the clearance testing ispositive.

Use the proper type insulation for the type of construction, and have thatinsulation installed properly. Fiberglass and "blown-in" cellulose insulationis pretty much worthless. We inspectors refer to cellulose insulation as"mold food". Insulation should provide an effective "building envelope". Abuilding envelope serves as a barrier to heat (thermal insulation), but also toair leakage (cold air infiltration, in the winter, and cold air loss, in thesummer), water intrusion (liquid water) and vapor movement (humidity,which will condense into liquid water). This type of barrier can only beachieved with a foam type insulation and the easiest way to have foaminsulation is the use of spray foam.

The two types of modern spray foam are open and closed cell foaminsulation, and they are meant to be used in two different areas of thehouse. Closed cell foam is used to insulate exterior walls. Closed cell foamhas small bubbles and will stop all water, vapor and air movement, as wellas heat movement. Open cell foam insulation has larger bubbles and will

allow a smallamount of moisturemovement throughthe foam. Whywould one want toallow any movementof moisture throughinsulation, you ask? Human nature beingwhat it is, mostpeople do notreplace their roofcovering until waterin already dripping down through the ceiling. By that time, however, the roofitself has already been leaking for a year of so, it just hasn't actually leakedthrough the interior ceiling (out of sight, out of mind). If closed cell insulationis used to insulate the roof area, it will further retard roof leaks from drippingand will allow the water to be retained in the roof decking, causing rot andeventual roof structural collapse. So roofs should be insulated with an opencell foam so that any leakage can be seen and the roof replaced before itbecomes an even bigger problem. Open cell foam also allows the buildingenvelope to be extended, outward, from the ceiling of the top floor of thehouse to the underside of the roof decking, sealing any attic areas (thespace between the ceiling and the roof) and better preventing heat loss (aswell as stopping the natural "stack effect" of the house).

Finally, make sure that the interior drywall is properly installed andprepared. Interior walls should be primed before painting. (And "paint andprimer in one" products are just a bad joke.) All door and window spaces(the air gaps between the windows and doors and their openings in theexterior walls) should be properly sealed (low volume foam). And, it isalways a good idea to properly control the humidity levels in the house. Inside humidity levels should be kept between 25 - 35%, year round. Use a

de-humidifier in the humid seasons (in Chicago, remember, Summer, Falland Spring are ALL humid). A good rule-of-thumb is this: If there iscondensation on the inside of the windows, it is too humid. If you getshocks when you touch metal objects, during the winter, it is too dry. Buyand use a good humidity meter in the house. It will help to keep the housecomfortable and save you money in air conditioning electrical costs.

Final thoughts on the (possible) future:

The Home Inspector's quandary - As professional, licensed and certifiedhome inspectors, in Illinois, we are called upon to serve our client's bestinterests. This is usually done during the standard pre-purchase homeinspection when a home is inspected for problems that may affect theclient's willingness to buy the property. But what does a home inspector dowhen they are discover the house or condominium unit that is clad with splitfaced block? Not knowing if the building was completely flashed and orwhether it was properly sealed, how can we best predict if your client's willhave problems with water, mold and large repair bills? How does theinspector properly protect the client?

The future, potential, calamity - With so many of split faced block housesand condominiums having been already built, and with the clear evidencethat many (if not most) where not built (or, to be fair, maintained) properly,what is the potential, worse case scenario? Long term water intrusion,through the block and parapet walls, can lead to water being wicked intothe ends of the wooden roof / floor trusses and cause the trusses to rot ortheir gussets to rust. The weight on these trusses will, eventually, causethem to displace (sag) or in extreme situations, break. A catastrophic failureis possible! (although, we hope and pray that we are being overlycautious). This will cause a portion, or all, of a roof or floor structure tocollapse down (called a pancake) onto the floors below. Given the pasthistory of Chicago buildings (rear porches and deck collapses, see here,from 2003, and here, from 2010, and here is the Illinois appeals court ruling,

finding that no municipal code inspectors in Illinois have any liabilitywhatsoever. With the tragic loss of lives already seen, is a future disasterpossible? Given what we and other inspectors in the Chicago area haveseen, this is a very real possibility.

Some years ago, a new exterior wall cladding material was also extensivelyused. Called EIFS (Exterior Insulation Finishing System, usually referred toas Dry-Vit, the name of the primary manufacturer) it was sometimes cheaplyinstalled. This lead to many buildings suffering from mold and wood rotproblems, and many homeowners having to pay for extensive repairs. When installed according to the manufacturer's recommended instructions,EIFS is a very good product but, as we have seen, builders often cutcorners to save money.

Many Real Estate agents, reacting to this situation, would automaticallycondemn any house that utilized EIFS, even if the product was properlyinstalled. To be fair, they were trying to represent their buyer's bestinterests, but in doing so that were writing off all EIFS clad buildings,without determining the building's actual condition. But in doing so, theywere also condemning thousand of EIFS properties to a scrap heap ofhouses that nobody wanted to buy. I fear that Split faced block buildingswill soon join that category.

To avoid this, as well as to avoid deaths and extensive property damage, itis very important that split faced block buildings be completely andprofessionally inspected and that condominium associations set aside therequired funds to do the necessary maintenance of their split faced blockbuildings. We would not want to see these properties turn into the newestwave of unlivable tenements.

As our company's motto states, "Hope this helps."

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