More on Split faced block

I am seeing a lot of split faced block buildings that were never sealed. To try to avoid getting sued, many of these builders and “sealing” the block (way after the fact) with a linseed oil product.

If you see this, dried crusty white stuff, on the surface of the block, the builder probably used linseed oil. The oil leeches out and combines with efflorescence, and this is the result.

In my experience, the best sealer is In Crete Systems Clear Coat. Have it applied during construction.

Hope this helps;


I’ve had good luck with this product Will.

Why are split-faced blocks more prone to issues than “standard” CMUs?

There are more and larger “pores” on the exposed surfaces for water to enter.


  1. More absorbant.
  2. Most times, the builders use them in a single wythe wall. Not a good idea, in the Chicago area.

Hope this helps;

Here’s one they didn’t finish.





To your photos:

  1. Was that split faced, or just in veneered cinder block?
  2. Notice, just furring strips. Most plans call for 2" furring strips, but the builder just splits a 2 x 4, which is not the same. Also, most plans call for 2" foil faced rigid foam (provided a duel moisture barrier at both the interior wall of the masonry and behind the drywall. I know that this is not the current national standard, but id works in Chicago, because of our weird climate. Most builder “substitute” 3 1/2 unfaced fiberglass crunched into 1 5/8" space. This is just a water trap.
  3. Notice how the joist pocked flashing is just plain crap.

Permission to use these photos, with attribution, Linas? I am preparing a paper for Inframation 2009.

Split faced block:

New concerns with this split faced block in Chicago.

And now this. Myself and some other inspectors are now seeing the floor and roof truss joists, which have been inserted into pockets in the split faced block and grouted (masonry in contact with wood, a real no-no), starting to rot. Soft and sinking roofs and unstable floor structure.

My big concern is that, in the near future, wee will see a roof or floor collapse that will pancake down and we will have an addenda to the old Chicago back porch collapse problem.

This could be a real big deal!

Comments on how to call this out?

Problem is ,you usually can’t see the pockets in a lot of these areas due to wall coverings and flooring.

I suppose unfinished basement areas might be a clue,but how often can you view the roof trusses?

May be a city problem in the long run.

We just can’t see through walls.

I just finished an article on the problem of split faced block in the Chicago area.

One point that I would like to be discussed is our obligation to the client, as well as our professional responsibility to not overly upset the market.

We can, very easily, see in the near future these buildings experiencing pancake collapses. Many of the older ones, that were sealed when they were originally built, are no ild enough for the original sealing to have worn off. And the condo associations, as is typical, has put off (or isn’t even aware of the need) the reauire maintenance.

We should inform our clients, but would this also serve to cast a taint on all split faced block buildings. If so, no buyer will want to purchase one and we would wind up with a LOT of abandoned buildings in this area.

What about insurance companies? If these companies see split faced block buildings are a losing proposition (not just from the potential risk of collapse, but also from water intrusion damage and mold) will they just start refusing to write homeowner policies for split faced block buildings?

And what duty does an inspect have to the client who is thinking about buying one? Do we tell them of our concerns? Are we duty bound to have water absorption test done? Do we call out that the joist, sill and coping stone flashing are missing? It has rained, prety much every day, for the past 2 weeks and water problems are very evident. What do we do if there is no rain for 2 to 3 weeks and the place has problems but they are not evident?

Just some thoughts and questions for you to consider. This is a real issue in the Chicago area. Is this problem seen in other areas, as well?

This is how it looks when demo’d, and the fix when they have to replace the roof trusses.

The steel ledgers are for the fix and not part of the original construction.

They are completely gutting and rebuilding the to floor.