Expert: Bruce E. Johnson - 5/27/2011

Question
Dear Sir,
I am looking at building one of safe rooms the FEMA suggests in the document FEMA 320, taking shelter from the storm. I was thinking of putting it in my garage and making it out of 2x4's, 3/4 plywood and dry stacked 4x8x16 light CMU. I wonder if stacking 4x4 posts or landscape timbers log cabin style and then sheathing them on both sides with 3/4" plywood would work as well.
I would like to make it 12x12,
Thank you in advance.

Ernest A Seemann

Answer
Hi Ernest, I guess it depends on what type of storm you are trying to protect against.  For an F4 tornado nothing short of a reinforced concrete bunker will be safe.  Dry stacking cmus is pretty much worthless in my estimation.  I suppose if you were to take some 4x4s and bolt them to a concrete floor and them lag bolt and stack them solid to one another alternating the corner laps and then sheathing them with plywood would create a safe room but you would have to make the roof of it solid timber as well and tie the roof timbers to the walls with hurricane straps. I hope this information helps, please feel free to write again regarding this or other matters sincerely bruce johnson.