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 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:
First rule of attic floor installs
When medical students complete the many years of study it takes to become a doctor, they ceremoniously take the “Hippocratic Oath”. 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.
The key to a successful attic flooring project is to complete the project without damaging the roof or floor structure, or weakening the attic insulation.
Attic flooring for storage space 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 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. It does this through a series of interconnecting load-bearing wood framing pieces known as “chords”. Adding storage to this finely tuned structural marvel risks weakening the roof system and violating building codes.
Also, since the attic insulation rests on top of the drywall, it will be much thicker than the bottom 2×4 chord of the attic truss. Adding flooring and storage on top of fiberglass insulation will compress it, squeezing out trapped air rendering it virtually useless.
However, if you keep the storage weight to a minimum, you may be able to build a storage platform above the insulation, by attaching supporting beams to the sides of the trusses. Even easier, you can also use a prefabricated attic floor kit designed specifically to raise the attic floor above the insulation.
For example, LoftZone StoreFloor is lightweight and very easy-to-install. LoftZone raises the height of the lower chord of the attic truss. This allows the full depth of attic insulation to work as intended. The metal beams are adjustable to take into account variable joist spacing. The system can bridge over pipes, uneven joists or other obstructions. The system also provides an air-gap between the top of the insulation and the underside of the board. This helps to remove any damp air that could cause condensation.
Building an attic floor over ceiling 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. The beams you’ll be installing the subflooring on top of are actually ceiling joists. Ceiling joists are designed to hold up a drywall ceiling and not strong enough to support a floor loaded with your old Encyclopedia Britannica collection!
If the attic were designed as living space, those ceiling joists would become floor joists and be much bigger. Ceiling joists are typically 2×8 lumber, floor joists are usually 2×10 or 2x 12 lumber. That’s a big size and strength difference between the two types of attic joists, even if the joist spacing is the same.
Lastly, your home’s energy efficiency almost always suffers when the attic is converted for storage. Since an average attic needs 16 inches or more 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 reducing the efficiency of the fiberglass insulation.
Tips and tricks to make attic flooring easy
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 attic flooring installation job unscathed.
Platforms Don’t Have to be Plywood
Maneuvering heavy, 4 x 8 sheets of plywood or OSB (oriented strand board) up to an unfinished attic is sometimes like trying to fit a square peg into a round hole. To make the job easier, use a circular saw to cut the plywood sheet first into (2) 2×8 strips which will be much easier to handle. Another option is to skip the plywood flooring 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.
Limit attic flooring
If you don’t need additional storage, think of flooring an area less than the entire attic, such as a small section around the attic door opening. This way you can preserve the maximum amount of attic insulation 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 decking
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 attached to the top of ceiling joists.
Attic Dek flooring provides additional storage space that supports up to 250 pounds, making it easier than ever to get those cluttered spaces organized. The sections are durable, 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.
Raise ceiling joists
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 attic floor boards.
On our radio program The Money Pit, we open each and every hour by inviting calls from “floor boards to shingles.” If your question is about how to install attic flooring, there are lots of fabulous attic flooring solutions and choices!