Flooring Methods to Reduce Vibrations

As a contractor, you probably already know about all the things that homeowners are concerned about.  Flooring vibrations is one of the most common complaints you may hear. Homeowners tend to assume that when their house is being built or remodeled that the flooring will be perfect and have no issues. The problem with this issue is that it is subjective to each person. For some homeowners, they will be happy no matter what.  For others, they will feel the vibrations immediately. There can be additions of furniture or other items in the home that may bring out the vibrations that may not have been noticed before. 

In order to attempt to reduce or eliminate vibrations, there are several things you can do as a contractor.  First, lateral bridging is an option but if it is not done perfectly then squeaking can occur down the road, rendering the work you did pointless. Some contractors may attempt to put the joists close together, but that actually does nothing for the vibrations in the floor. So you may better be prepared to deal with any homeowner complaints, here are the common live load deflections used in the United States. 

Live load deflection limited to L/360 

This is the minimum deflection that can be used based on the United States building codes. L/360 is structurally sound to be able to carry the load but means there will be a higher chance of floor vibrations being noticed. If you know for a fact that your homeowner will not care about this issue, you can use this live load deflection. It might be a good idea to discuss the possibility of floor vibrations with your customers.

Live load deflection limited to L/480 

L/480 is 33% stiffer than L/360 so you would think that this would almost eliminate any potential issues. This is the most commonly used deflection for residential buildings and most contractors.  Most likely, you are using this with your current jobs, and that is okay but there still is a chance of some flooring imperfections. Using joists that are 9½” and 11⅞” deep will certainly make issues more likely with an attached ceiling. 

Live load deflection limited to L/960

The best deflection option out there for reducing floor vibrations is L/960 as it is 100% stiffer than L/480. Homeowners that will be very picky and notice any amount of floor vibration, or will specifically go looking for it, are great proponents for this option. 

Customer satisfaction is of utmost importance to any business owner, but almost more so for contractors. You can build a homeowner the most beautiful house with quality craftsmanship and they still might find an issue if they have floor vibrations.  Again, something as small as adding a kitchen island can cause these vibrations to be more noticeable to those who may not have noticed before. Using the stiffer live load deflection may help keep your customer satisfaction high.