Does your house suck? (Water, that is!)

We were unsure about what to title this blog post. The title is a little mis-leading. But you have read this far, so we have your attention. This article deals with split faced block construction in residential homes and condominium buildings. What we have learned in the last 20 years is that this type of construction can cause some major problems with water entry into the home. You need to know what to look out for.

What is split faced block?

Split faced block is a type of masonry construction that is used in residential and commercial construction. In most cases, the walls are constructed in a single wythe style. This means that the wall is one thickness of masonry block. Traditional masonry construction used 2-3 thicknesses (wythes) of brick or block to make up the wall structure. “Solid masonry”, as it is called, had the benefit of mass to prevent water entry. Proper flashings, weep holes and other accessories also help to prevent water entry into the wall cavity. Split faced block has only one wythe of hollow block to prevent water from entering. There is not much room for error.

The problem is that the walls suck, and then do not drain properly.

The single wythe construction method is only part of the problem. Water can be sucked into the walls in certain conditions. While split faced block may be more susceptible to allowing water to enter, more importantly proper ventilation, drainage accessories (flashings, weeps, etc.) are necessary to drain the water out of the wall. Often, these details are omitted. This has resulted in water entry, mold growth, and structural failure of wood supporting structure. While the original design of these buildings is questionable, the actual construction of the walls is the main culprit in most cases.

roof damage due to split face block
Badly deteriorated roof trusses in a split faced block building

Home inspectors at Dunsing Inspections, as well as other experienced inspectors and contractors have found that the wood framing inside of some of these buildings may be slowly rotting away. It may simply be a matter of time before structural failure and collapse of a flooring system occurs. Masonry contractor Bob Kelly of Wickright General Contracting ( has investigated and repaired many of these buildings and has determined that the entire roof or floor structures need to be rebuilt in some cases. His company has had to remove the roof structure and rebuild or replace the supporting roof and floor trusses or rafters. They have a patented accessory for masonry walls that have these types of moisture problems. Still do not believe how much water can be stored in one of these walls? Go here for a short video showing the amount of water that can accumulate in a wall cavity! or go here to see a video that shows what some homeowners have had to deal with.

Why not seal the walls to prevent water entry?

Sealing the walls was the common “repair” recommendation for many years. We used to recommend it on a frequent basis. This repair method required continual maintenance and reapplication of sealers every 5-7 years. To make matters worse, the sealing job was thousands of dollars, even on a small building. The industry has come to realize that sealing alone is not the answer. We have changed our recommendations along with countless other consultants, inspectors, and contractors.

rilem outside
A RILEM test on a masonry structure

A visual inspection cannot determine if the walls are allowing water entry to occur or if damage exists in the wall cavity. Moisture absorption testing using a RILEM tube is a commonly accepted method to determine if water entry is likely to occur. However, this testing is beyond the scope of a general home inspection. Go here for a short video showing how a RILEM tube test is performed. RILEM Test video

The best method to determine if there is damage to a roof or wall cavity is to remove interior finished surfaces. Unfortunately, during a real estate transaction, this is usually not practical. A visual inspection, moisture testing, and possibly thermal imaging appear to be the best tools and methods to determine if there is a moisture (mold) problem in your building.

As they say, “This sucks!”

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