How to Floor Your Attic Without Wrecking Your Roof

Attic spaces are tough to work in.  Since they are outside the “living space” of your home, finding the right attic flooring solution requires special consideration. However, flooring your attic can make it a perfect place for storage. Doing so the wrong way means that you could weaken your structure, squash your insulation or worse, find yourself with one foot planted firmly through the sheetrock ceiling below!


Fortunately, there are attic flooring solutions that work well in the often harsh and unheated environments.  Here’s where to begin:

When medical students complete the many years of study it takes to become a doctor, they ceremoniously take the “Hippocratic Oath” at graduation.  This oath includes well known words that homeowners who are considering flooring their attics are wise to remember:  first do no harm!

For the most part, attics were not designed as storage spaces.  They are a part of the raw underbelly of structure that holds a house together and protects it from the elements.  Because of this, installing a floor to an attic always involves some level of disturbance.

attic flooring

Attic flooring above trusses

If the roof structure of your home was designed with prefabricated trusses, your attic was definitely not designed for any storage.  There are several reasons for this.  First, adding weight to the top of the bottom 2×4 that makes up the truss is a big no-no.  Roof trusses are specifically designed to take the weight of the roof (and the snow, wind, rain, etc.) and distribute it downward and outward to the load-bearing exterior walls through a series of interconnecting wood framing pieces known as “chords”. Adding storage to any other part of this finely tuned structural marvel risks weakening the roof system.

That said, if you keep the storage weight to a minimum, you may very well be able to build a storage platform above the insulation, by attaching supporting beams ot the sides of the trusses, or even using a prefabricated attic floor kit.

Building an attic floor over standard floor joists

If your home was built with standard conventional lumber, your risk of causing structural imbalance isn’t nearly as high; however, you still need to be sensible when installing an attic floor.  Remember that the ceiling joists were designed to hold up a ceiling and not to support a floor loaded with your Encyclopedia Britannica collection!

Lastly, your home’s energy efficiency almost always suffers when the attic is converted for storage.  Since an average attic needs 10 inches or so of insulation, the insulation is always thicker than the ceiling joists or trusses.  As such, adding a floor can cause the insulation to compress, thus squeezing out the insulating ability of the fiberglass.

With all these challenges, you might start thinking that attic flooring installation is impossible.  It isn’t, but you’ll need a dose of common sense to execute the job of installing an attic floor properly.  Here are a few tips to help you and your house get through the job unscathed.

  • Platforms Don’t Have to be Plywood – Maneuvering  a heavy, 4 x 8 sheet of plywood up to the an attic is sometimes like trying to fit a square peg into a round hole.  To make the job easier on you, cut the plywood first into (2) 2×8 strips which will be much easier to handle.  Another option is to skip the plywood altogether and use dimensional lumber.  1 x 6 #3 spruce is a step up from pallet quality wood but makes a fine usable floor in an unfinished attic  space.
  • Don’t Waste Energy – If you don’t need a lot of storage, think of just flooring part of the attic, such as a small section around the attic opening.  This way you can preserve the maximum amount of energy efficiency in the rest of the home.  Since homes tend to be colder the closer you get to the exterior walls, keeping this floored area to the inside center of the attic is smart.
  • High Tech Deck – Another innovative option that is specifically designed for attic flooring is a product called “Attic Dek.”.  Attic Dek®  is a specially designed attic floor system that consists of 16″ or 24″ squares that attach directly to the top of floors joists.  The sections are lightweight, easy to handle and resemble floor grates that provide plenty of ventilation for insulation below.  They attach with just a few screws and allow you to build a safe, secure storage platform in your attic in just minutes.

attic flooring

attic flooring

Also, if the attic insulation is thicker than your ceiling joists, you can raise the height of the joists to above the insulation by attaching 2×3’s to their top edge before you attach the floor boards.



Information Courtesy of Tom Kraeutler

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