Expert: Bruce E. Johnson - 11/14/2011

Question
I want to put in a wolf stove that weights 1000lbs in my kitchen, the floor joists are 2x8s 16 inches on center spanning 12 ft. I want this stove placed as an island which is close to the middle of the floor space.  the stove is 34" by 60" on 4 legs (if that makes a difference.) Do I need to add a header in the basement?
thanks
Bernetta

Answer
Hi bernetta,  I plugged the floor system information into a span calculator and based on the information given this floor system is capable of 60 pounds per square foot of live load in a 12' span of southern pine..other wood species will vary in their support capabilities. Your new stove takes up an area of a little less than 15 square feet so multiplying 15 sq ft  times 60 psf it appears that your floor is slightly undersized and may possibly deflect under the weight of 1000 pounds beyond its acceptable design load.  You can strengthen this area by adding (sistering) additional floor joists alongside your existing ones.  Or as you mentioned provide a header for additional support.  You didn't mention whether or not there is "bridging" in this span of joists.  Bridging is "X" bracing between joists or solid blocking.  The bridging helps keep the joists from deforming under concentrated loads.  By adding a row of properly installed bridging down the center of this span you might be able to increase your live loading enough to keep these joists from sagging under the newly added weight..I hope this information helps, please feel free to write again regarding this or other matters, sincerely Bruce Johnson..bejohnsonconsulting.com