From Dusty Storage to Dream Room: The Right Way to Convert Your Attic

Thinking about turning that dusty old attic into a cozy new living space? Before you start dreaming of your new bonus room, home office, or playroom, there are some critical structural considerations you must address. Unfortunately, it’s not as simple as slapping on some drywall and laying down new flooring. Let’s walk through the key points you need to consider to ensure your attic conversion is safe, functional, and up to code.

1. The Importance of Floor Load Capacity

Your attic’s existing floor system wasn’t likely designed to handle the weight of a living space. Typically, attic storage is rated for a live load of 20 pounds per square foot (psf). However, once you convert that space into a living area, the required live load doubles to 40 psf. There are some nuances to this figure. Live loads of 40 psf assume a dwelling area, which are considered rooms where more people are likely to aggregate like living rooms, kitchens, and bonus rooms. Rooms such as bathrooms, offices, and bedrooms only require 30 psf, which can make all the difference for load calculations. Be certain you are submitting the appropriate room titles during permitting.

So, what does this mean for your project? The floor structure must be thoroughly evaluated to determine if it can handle the increased load. If the floor system can’t meet the new load requirements, you’ll need to reinforce it to prevent potential sagging or structural damage.

2. The Ripple Effect on Your Entire House

It’s not just the attic floor that needs to be up to snuff. The entire structure of your home below the attic must also be capable of supporting the additional weight. This means an engineer will need to create a detailed drawing of your home, assess all existing openings (like doorways and windows), and trace the load path down to your crawlspace or foundation.

This load path analysis ensures that every structural component from your attic down to your foundation can bear the new load without causing undue stress, cracking, or failure. It’s a critical step that can’t be overlooked.

3. Egress: A Safe Way Out

Any new living space needs a safe way to exit in case of an emergency since stairways leading to the attic can act like fireplace chimneys. For attic conversions, this typically means installing an egress window. But adding a window isn’t as simple as cutting a hole in the wall.

Installing an egress window often requires cutting and headering off rafters, which affects the structural integrity of your roof. An engineer will need to size the header correctly and ensure the remaining rafters can withstand the new point load introduced by the window. This is another area where expert planning and execution are essential.

What to Expect from a Floor Evaluation

When your attic conversion project kicks off, be prepared for some surprises during the floor evaluation. Here are a few things you might encounter:

• Exposing Structural Openings: If you have large openings, like a 6-foot-wide doorway between your foyer and office, and it’s determined that this opening is structural, you might need to remove some drywall. This allows the engineer to inspect the header’s depth and the number of supporting studs.

• Strengthening First-Floor Girders: The beams in your first-floor system might need reinforcement to handle the extra load from the attic. This could involve adding more material to the beams or even replacing them entirely.

• Strengthening Attic Sub Floor: If you house is older, it likely only has 1/2” thick floor sheathing. Your new living space must adhere to modern code; therefore, the minimum subfloor thickness should be not less than 5/8” thick. This is often achieved by adding additional layers of subfloor to what is already existing. Be sure to use construction adhesive and screws to minimize floor squeaks between the two wood materials.

• Strengthening Long Rafter Spans: Your rafters are unlikely to change; however, when I was working in an engineering capacity, I had to have contractors fortify rafters on a few projects due to the increased dead loads imposed by the drywall and insulation. Though this usually only increases loads by 5 psf, if your rafters are already spanning to their max, the added load can be the straw to break the camel’s back.

• Addressing Previous Modifications: If walls were previously removed and replaced with beams, these beams might no longer be sufficient for the increased load. In some cases, you may even need to extend the footings to distribute the new loads safely. This brings up a very important point. If you are removing a wall and think you may want to convert your attic in the future, ask your engineering to assume the attics floors are 40 psf when designing the new opening. On top of that, ask them to state in their letter than the beam was designed assuming an attic load of 40 psf. You’ll thank me later.

Final Thoughts: Do It Right the First Time

Converting your attic into living space is a fantastic way to add value to your home, but it’s not a project to take lightly. Every structural element, from the attic floor to the foundation, needs to be carefully evaluated and potentially reinforced to ensure safety and durability. Skipping steps or cutting corners can lead to costly repairs down the road—or worse, serious structural damage.

Before you start, consult with a structural engineer who understands the complexities of attic conversions. It’s the best way to ensure your new space is safe, functional, and built to last.

Got an ongoing project that you’re just not quite sure about and want a second opinion? Consider booking a service with Kurtz Residential today!