Q: For pre-insulated Concrete Masonry systems, what is the difference between code based R-values & effective R-values?
-Misleading Effective R Values
A: Dear MERV, For concrete masonry, effective R-values typically mean that the R-value is adjusted to account for the thermal mass of a CMU wall system. It can also take into account other variables, such as thermal lag or annual averages. Code based R-values are calculated based on either test data or...Read More
Q: Is the compressive strength (PSI) of Concrete Masonry Units effected by density and what are the main performance variations associated with the different densities?
-Are Lightweights Better In the Envelope?
A: Dear ALBIE, For architectural units, aesthetics are a major consideration. The light weight aggregate available in the Northeast is a very dark grey, which is visible in ground face & polished units. For standard grey block, mix designs can have different densities, depending on the amount of light weight aggregate used...Read More
Q: We are designing a large health care facility. What role can Concrete Masonry play in creating a resilient structure?
-Resilient Construction Has Extreme Longevity
A: Dear RaCHEL, Concrete masonry construction has strength, durability, longevity, fire resistance, seismic and blast resistance, all of which contribute to the resiliency of the built environment. The durability of concrete masonry construction is well known and vital during the more visible aspects of natural disasters such as floods, hurricanes and tornadoes....Read More
Q: We have a project which is over budget and has limited space. Is it possible to eliminate catch basins and retention ponds if we use a Permeable Articulating Concrete Block (P-ACB) paving surface?
-Stormwater Alternatives are a Must-have
A: Dear SAM: Depending on the soil type and specific site conditions, it is possible to eliminate traditional storm water infrastructure, such as catch basins and retention ponds, by using a high performance permeable articulating concrete block (P-ACB) paving surface. These systems allow for a more natural, vertical infiltration path, recharging local...Read More
Q: How are fire ratings of Concrete Masonry assemblies calculated, and for fire code compliance, are listing services such as UL® required?
-Fire Rating Expertise Desired
A: Dear FRED: Section 721 of the IBC recognizes several methods to calculate the fire resistance for CMU walls. The equivalent thickness method is the most commonly used, and the most cost effective. It takes into account extensive industry research, the results of ASTM E-119 testing and aggregate type. Equivalent thickness...Read More