An 8-inch CMU block with closed-cell insulation has an R-value of approximately 7. Typical 2×6 woodstud framing with fiberglass insulation or spray foam insulation achieves an R-value of approximately 19. The higher the R-value, the more a material prevents heat transfer. The R-value is a measure of the ability of heat to transfer from hot to cold through materials such as insulation. Walls, build time can be easily extended by three to five months. On a typical house project that utilizes CMU over stick-framing for the exterior Only after the CMU walls are up can the wood framing begin. The CMU wall can only be raised a specified height each day, so more time is required for rebar installation and forįilling CMU cells. Last, even after block masons have completed a wall, wood framing and carpenters are needed to build a second wall inside the CMU to accommodate mechanical piping and wiring.īuild time is also lengthened when contractors use CMU construction. scaffolding) are involved in constructing a block wall as compared to a woodframed wall. In both cases, wood stud framing materials are still required. Second, the cost of CMU, rebar, mortar, concrete fill, etc., are more expensive than plywood sheathing. The labor available for stick frame construction. First, the labor pool for block masonry is much scarcer than Labor and materials costs are higher for concrete block. This is advantageous from a cost perspective, while the combination still captures the advantages of having a better substrate for stucco and being easier to repair after potential flooding from heavy rainfall like we’ve seen over the last several years.ĭISADVANTAGES OF CONCRETE BLOCK CONSTRUCTION:Ĭoncrete block is considerably costlier than stick-frame construction. Water coming in over time will rot out exterior sheeting, window and door headers, and structural wood framing.įor multi-story projects in Walton County, we have observed an increased use of CMU on the first level with 2×6 wood framing on upper levels. For example, if a garage were to flood, it would be much easier to dry out or repair damage to CMU walls. While the termite population is alive and well in Florida, maintaining termite inspections and treatments (bond) reduce termites as a determining factor in choosing which exterior wall system to use.įlood & Weather Resistance – Moisture IntrusionĬoncrete block is more forgiving to water and moisture intrusion. Still, the sleepers or wood framing pieces attached to the inside of concrete block walls are still susceptible to termites, but the potential damage to the overall structure is diminished because the wood strips are not a structural part of the home and can easily be replaced. Stucco over a CMU substrate performs much better in the long run as compared to wood framing, provided proper use is made of expansion joints, as concrete and stucco also have some movement due to thermal changes.ĬMU wall framing has an advantage over wood-framed construction. Furthermore, wood framing has more potential to move as wood dries out over time. Given our location in close proximity to the Gulf of Mexico and in a high wind zone, CMU walls are less likely to move during high winds than wood-framed walls. If a fire occurs where CMU walls are used, wood studs (sleepers) would most likely be damaged while the CMU may or may not be salvageable. While I agree with this notion, either type of construction, in accordance with location, is designed by the engineer to meet current building codes and to withstand 140-mile-per-hour wind speed, whether constructed from CMU or wood framing (with various strapping and fastening mechanisms).ĬMU is indeed more fire resistant than wood studs and plywood sheathing, although wood framing is still used and attached to the inside of CMU walls to allow for concealment of mechanical piping and wiring. There is a preconception that a concrete block house is stronger than a 2×6 stick-frame house. Let’s explore some of the benefits and disadvantages of using concrete block construction versus wood framing.ĪDVANTAGES OF CONCRETE BLOCK CONSTRUCTION OVER WOOD FRAMING: One of those is the trend toward constructing homes using concrete block, which is commonly referred to as concrete masonry units (CMU).Ĭoncrete block construction is traditionally more common in central and south Florida, while wood-framed exterior wall construction is prevalent along the panhandle, but now, those building new homes have more choices, unless neighborhood design codes strongly encourage or dictate the type of exterior wall construction that must be utilized. Since I began building homes in Walton County in 2005, I’ve seen numerous shifts in construction methods and materials used in residential homes.
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