I live in Florida, and my house was built in 1980 with a pier and beam foundation. The 2x10 beams that support the house sit on some stacked Concrete Masonry Unit (CMU) blocks, which are hollow in the center. They've been like this for 45 years, but I'm planning to install a few more support beams to stiffen the floor. I'm wondering if I should fill those hollow voids with Quikrete concrete to enhance their strength. Is this a good idea?
2 Answers
Filling those voids won't add structural strength unless you incorporate rebar as well. If you really want to improve the strength, think about adding some rebar with your Quikrete for better support.
It's really up to you! Generally, filling the voids in the CMU can be safe. Just keep in mind that while it won't increase the compression strength significantly, it can improve shear strength, which is beneficial for earthquake resistance. One downside is that it might increase the moisture transfer to the beams if the ground underneath is wet.