Leaks Through Split Face Block Walls
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 common brick. In fact, if I was blind, I would say it looks exactly like chiseled stone.
Left: Mark Meshulam investigating a leaking split face block wall
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.
It’s easy to trash split face block as a “bad” material and to condemn the developers as greedy and evil. But from what I am seeing, these developers tried to put together a decent product. They used nice exterior design and decent interior finishes.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.
Right: Split face block wall failing a water spray test
Whomever deserves blame for the split face block fiasco, the unfortunate current owners are left holding the soggy bag.
Read more about leaks in split face block walls, and see the water test video here:
Leaks Through Split Face Block
Project Manager, Construction Engineer, Program Coordinator, Program Management Officer, Program Management Specialist, Environmental and WASH specialist
7 年from the photo the main reason is the joints might new requirements on joints performance
Construction Manager- New Embassy Compound, Mexico City, Bureau of Overseas Buildings Operations,
7 年I used split face block for years in Las Vegas. They are typically meant to be used as an Architectural embellishment. A typical installation was as a privacy perimeter wall around a subdivision or a facade on a tilt up office building. Suppliers never represented them as a water tight barrier.
Deputy Chief of Party in Ukraine. Professional Engineer (PE), MBA
7 年A very casual keyword search of IBC 2009 does not show many requirements at all for above-grade waterproofing for walls. These walls may be code compliant, but underperforming. Perhaps it's time for building codes to address this issue. In the meantime, it is always best to use the services of an experienced design engineer who may understand deficiencies in minimum code requirements.
Architect
7 年I'll just add that it's not just split face- all exterior single-wythe CMU walls will leak. There are too many different forces acting on the wall- thermal, wind, seismic, hygrothermal, etc. You can use all the additives and sealants you want but fundamentally there is too much porous surface and material interfaces (joints) for it to ever be a satisfactory system. by itself. CMU can be effectively as an exterior face in a multi-wythe wall where there is an airspace and air/water/moisture barrier and an adequate pressure neutral drainage plane to ensure there is drying annually to prevent saturation.
Building Envelope Product Developer Ty-das Building Products LLC
7 年If one likes the look of split face block, a more water resistant wall assembly would be a split face cavity wall with a fluid applied AVB/WRB covering the face of the structural wall. Outbound rigid insulation would add thermal and insulating value, which combined with thermal mass provides excellent overall wall performance and fire safety. I'm 32 years into owning a structure as described and am thrilled with the low maintenance and operating cost experienced so far. I did pay a premium for said initial cost but, would do it all over again given the same circumstances.