“But I thought this house was concrete block!” is a comment we hear often, with a sigh of exasperation, from our inspection customers when we tell them that the stucco walls of their future home are constructed with wood studs and plywood sheathing. The stucco is simply a surface finish. If you grew up in South Florida in the bygone era of the 1950s through the 1980s, like we did, stucco walls meant it was a concrete block house about 99% of the time.

    But construction methods have changed throughout all of Florida and, today, a stucco finish could be synthetic stucco (also called EIFS), or hard-coat stucco over expanded metal lath on a wood stud wall, or stucco on concrete block. 

    Here are two ways to determine the type of house structure hiding under the stucco surface:

1. Hard-Coat Stucco and Synthetic Stucco (EIFS - Exterior Insulated Finishing System) over a wood frame wall will sound slightly hollow when you pound on it with your fist. EIFS is a thin finish over an insulating panel, will not feel as solid as hard-coat stucco, and the finish will be smoother. Stucco over concrete block will feel like solid rock.
2. Windows in wood frame walls are set close to the outside face of the wall, typically within 1-inch or less, but windows in a concrete block wall are recessed about 3-inches.
   

    Be careful not to make the mistake in assuming that a house is 100% concrete block or wood frame. Some homes are combination of the two, most often a concrete block house with a wood frame and stucco addition.

    There is actually one more way to verify—and with certainty—that a stucco home is wood frame or concrete block, and that is to look at the top of the wall from the attic. We recommend that you leave that chore to your home inspector. 

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To learn more about exterior walls and structures, see these other blog posts:

• What are the common problems with concrete block homes?

• What are different types of exterior wall construction for a house?

• What is the average lifespan of a house foundation?

• What causes vertical cracks in fiber cement siding planks?

• What causes raised white lines of residue on a block wall that are crusty and crumbling? 

• What is the difference between soil subsidence, heave, creep, and settlement? 

• How much ventilation is required for the under-floor crawl space of a home? 

• What causes stair-step cracks in a block or brick wall?

• What causes a horizontal crack in a block or brick wall? 

• How can I tell if a diagonal crack in drywall at the corner of a window or door indicates a structural problem?

• What causes the surface of old bricks to erode away into sandy powder? 

• What are the pros and cons of concrete block versus wood frame construction?

• Should I buy a house with a crawl space? 

• Why is my stucco cracking?

• Should I buy a house that has had foundation repair? 

• What is a "continuous load path”?

• Should I buy a house with asbestos siding?   

• How can I tell if cracks in the garage floor are a problem or not? 

• What do you look for when inspecting vinyl siding?

• Why is housewrap installed on exterior walls under the siding? 

• How do I recognize serious structural problems in a house?

• Why did so many concrete block homes collapse in Mexico Beach during Hurricane Michael? 

• How can I tell if the concrete block walls of my house have vertical steel and concrete reinforcement?

• Should I buy a house with structural problems? 

• What are those powdery white areas on my brick walls?

• What causes cracks in the walls and floors of a house?

• How can I tell if the exterior walls of a house are concrete block (CBS) or wood or brick?

• What are the common problems of different types of house foundations? 

• What are the warning signs of a dangerous deck?

• How can I tell whether my house foundation problems are caused by a sinkhole or expansive clay soil?

        Visit our EXTERIOR WALLS AND STRUCTURE page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.