Did you know your home came with engineered truss drawings?
Truss drawings are not hidden. They’re just never presented to homeowners.
Most people believe their garage ceiling can hold heavy storage because nothing has fallen down yet.
This feels logical — but it’s not how your home was engineered & designed.
The truth lives in one document most homeowners never see: the engineered truss drawings. This page explains what those drawings actually say — and why “zero” is the only number that matters when it comes to your ceiling.
What Is a Truss Drawing?
It tells them:
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how wide the garage is
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what kind of roof it has
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how much weight each part is allowed to carry
Engineers do not guess. They only design for what is written on this page.
The truss image above is a real truss drawing, not a diagram or a marketing graphic.
Loading Criteria / “Box A”
The Most Important Part of the Drawing
Every truss drawing contains many sections, but everything starts with Loading Criteria (labeled A on the drawing).
This box is the rule sheet. It tells the engineer what loads are allowed before any math is done.
If a load is not listed here, it is:
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not calculated
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not checked
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not verified
Nothing later in the drawing can change this.
What Is “BCDL” and What Does It Mean for Your Ceiling?
BCDL stands for Bottom Chord Dead Load.
On an engineered truss drawing, this value appears in the Loading Criteria section
(Section A on the drawing).
On the drawing shown above, "Section A" lists:
BCDL = 10 psf
The 10 means 10 pounds per square foot.
That means for every 1-foot by 1-foot square of ceiling, the truss was designed to carry 10 pounds total.
Bottom Chord Dead Load literally states what the ceiling was designed to hold.
This is a permanent weight that hangs from the ceiling forever.
On a truss drawing, this number represents the weight of:
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drywall (the ceiling boards)
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insulation (the material that keeps your house warm)
In simple terms: The ceiling was only designed to hold the ceiling itself. Nothing more.
What the Ceiling Can't Carry
BCLL stands for Bottom Chord Live Load. On your home’s official drawings, this number is usually 0.
Here is what “0” means for your garage:
No storage.
No bins. No bikes.
No hanging ceiling racks.
In simple terms: The ceiling was never designed to hold extra stuff.
Zero means zero.
Why “It Hasn’t Fallen Yet” Doesn’t Change the Design
Engineering is not based on luck or time. It is based on rules and assumptions written from the initial design.
A structure can survive loads it was never designed for — until it doesn’t.
That does not mean those loads were allowed. Design intent matters more than survival.
Why Box "A" Controls Everything
Every force, reaction, and stress shown elsewhere on the drawing comes from the loads listed in
"Loading Criteria."
If storage weight is not written there, it is:
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not calculated
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not checked
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not verified
Nothing later in the drawing can change this.
The Secret of Gusset Plates
It isn’t just the wood that has limits. It’s also the metal connector plates — called gusset plates — that hold the truss joints together.
These plates are designed and tested using national standards.
They are only approved to carry the exact loads listed on the truss drawing.
Nothing more.
Why This Matters?
Gusset plates are only considered valid when they are used exactly as the truss was designed and sealed.
If a truss was engineered with a Bottom Chord Live Load (BCLL) of 0, the plates were never checked for hanging storage.
Any added hanging weight falls outside what they were tested to handle.
In simple terms:
The plates were approved for the ceiling as designed — not for extra weight added later.
Direction Matters
These plates were designed to hold your roof together by handling forces along the truss, not heavy weight pulling straight down.
Think of it like Velcro:
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very strong when pulled the right way
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much weaker when pulled at the wrong angle
When you hang a ceiling rack, you pull on those metal teeth in a way they were never designed to resist.
Why This Connects to “Missing Loads”
Because the ceiling was designed for zero extra weight, the plates were only tested for:
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the wood
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the drywall
When storage is added later, it becomes a "missing load" — a load that was:
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never calculated
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never tested
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never approved
What the Building Code Actually Says
International Residential Code (IRC)—Section R802.10.4)
Most homeowners think they are just “adding a shelf.” The building code looks at trusses differently.
IRC Section R802.10.4 states:
“Truss members and components shall not be cut, notched, drilled, spliced, or otherwise altered in any way without the approval of a registered design professional.”
In plain terms:
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trusses are regulated structural components
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drilling into them counts as an alteration
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any alteration requires engineering approval
This rule exists because trusses are designed as a complete system, based on the loads listed in the truss drawing.
A Quick Note About “600 lb Rack Capacity”
Many ceiling-mounted racks are sold with weight capacities of 400 lbs - 800 lbs.
That number describes what the rack itself can hold, not what your ceiling or trusses were designed to carry.
If the truss drawing lists BCLL = 0 psf, then any hanging load—no matter the rack rating—was never included in the design.
A strong rack does not change a zero-pound ceiling allowance.
The Truss Engineer’s Seal Matters
At the bottom of the truss drawing is a licensed engineer’s seal.
That seal makes it a legal design document submitted to building departments.
They are the actual design limits of your home. These are not marketing numbers or worst-case guesses.
If ceiling storage were meant to be included, it would be required to appear in the "Loading Criteria." It doesn’t.
The Simple Takeaway
If hanging ceiling storage is not listed in the loading box, it was never part of the design. This is not opinion. It is what the drawing says.
The Engineered Solution?
ARackAbove, freestanding overhead storage engineered by Steve Schindehette specifically to respect these numbers.
Instead of adding a missing load or altering your trusses, it uses freestanding uprights to transfer 100% of the weight to the garage floor.
It lives in the overhead dead space between the garage door opener and the front wall of the garage, claims no usable floor space, and keeps your home’s engineering — and the law — intact.
It is the only freestanding overhead solution in the world that lets you use the vertical cube of your garage without touching damaging your structure or ceiling.
Legal & Intellectual Property Notice
ARackAbove is a patented, freestanding overhead storage system designed to address the structural limitations outlined above.
Certain architectural and load-transfer elements are protected under U.S. Patent law.
