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Backyard Building - 18' x 21'

Is a lack of storage cluttering your life?  The backyard building kits from Mueller provide everything you need in one affordable package.  It’s the ideal solution for the backyard storage you need.


  • Choose From:  Walk Door Size:  5'4" x 6'4" or Roll-Up Door Size:  5'9" x 6'5"
  • Over 30 colors to choose from.
  • All steel frame (optional galvanized frame available)
  • 26 gauge wall and roof sheets featuring 30-year limited warranty paint
  • Trim package


  • Erection drawings
  • All required screws and sealers
  • Door
  • Pre-cut parts
  • Detailed instructions


     Optional Floor Kit:  

     Optional Mid Girt:  

 View Installation Guide - 18' x 21' with Floor Kit

 View Installation Guide - 18' x 21' with Slab

Mueller does not represent these backyard buildings to meet any specific code or engineering criteria.  These buildings are intended to be erected in geographical locations which do not require engineered loads for buildings under 400 square feet.

Prices subject to change without notice.


Available Colors…

*  Colors may vary by monitor settings.  Please contact us to get the most accurate color representation.  We will be glad to provide you with color samples. 

**  Galvalume Plus has no uniformity of appearance guarantee.  Each individual sheet, even upon delivery, may have a different color, gloss, sheen, texture or spangled appearance.  If uniformity of appearance is desired, a painted product is required. 

Click here for information about our paint warranties.