How to Understand the Alumawood Engineering Packet

What This Packet Actually Is

It is proof your patio cover:

• Resists wind

• Supports weight safely

• Has properly sized beams, posts, and footings

• Meets building code

It is structural approval documentation — not marketing material.

The 10 Things That Matter

You do not need to understand the whole packet. You need to confirm these ten items:

1. Structure Type

• Attached or freestanding

• Lattice (open) or solid roof

All tables and sizing depend on this choice.

2. Wind Speed (Design Load)

Typical Residential Wind Speeds (2021 IBC – Risk Category II)

• Menifee: 110–115 mph

• Temecula: 110–115 mph

• Murrieta: 110–115 mph

Exact requirement depends on parcel location and exposure (B or C).

Wind design directly affects:

• Post spacing

• Beam size

• Footing size

• Attachment hardware

Incorrect wind speed = under-designed structure.

3. Width × Projection × Height

The packet is based on actual dimensions.

• Width (left to right)

• Projection (distance out from house)

• Height (post height)

Changing any of these changes the structural requirements.

Taller posts reduce allowable span.
Longer projection increases rafter demand.
Wider structures increase tributary load.

If the installed size exceeds what the tables allow, it is not compliant.

4. Rafter Span

Span = the distance a rafter carries load without support.

Longer span requires:

• Larger profile

• Thicker aluminum

• Reduced spacing

The packet tables define the maximum allowable span. Exceeding it leads to deflection and long-term sagging.

5. Overhang Limits

Overhang is the portion extending past the beam.

Engineering limits overhang because it creates leverage.

Too much overhang increases:

• Uplift forces

• Beam rotation

• Connection stress

Overhang is not a cosmetic detail. It is structural.

6. Live Load

Live load includes:

• Maintenance weight

• Rain accumulation

• Rare snow load (if applicable)

Typical live load used for patio covers:
10–20 psf depending on jurisdiction

If the engineering packet does not match required live load, it is not compliant.

7. Post Spacing

Tables specify maximum spacing.

If posts are spaced farther apart than allowed:

• Beam stress increases

• Deflection increases

• Long-term performance decreases

Wider spacing is often done to “make it look cleaner,” but it must match engineering.

8. Footing Size

Footings resist:

• Gravity

• Wind uplift

• Lateral movement

The packet defines:

• Diameter

• Depth

• Uplift vs constrained footing type

Undersized footings are one of the most common issues in unpermitted installations.

9. Metal Gauge (Thickness)

This is critical and often misunderstood.

Aluminum structural members are manufactured in different thicknesses (gauges).

Thicker metal:

• Has higher load capacity

• Deflects less

• Resists long-term fatigue

Thinner metal:

• Costs less

• May meet minimum span but deflect more

• May not meet higher wind criteria

Engineering tables assume specific material thickness.
If a thinner member is substituted, the span tables no longer apply.

Gauge directly affects:

• Beam strength

• Rafter performance

• Wind resistance

Material thickness is structural, not cosmetic.

10. Proper Detail Sheets

A complete permit set includes:

• Configuration sheet

• Span table used

• Beam/post table used

• Footing table used

• Connection details

Random pages are not a complete engineered submittal.

IMPORTANT: Permits and Plan Compliance

Many patio covers are installed without permits.

Common problems:

• Wind speed never verified

• Posts spaced wider than allowed

• Footings smaller than required

• Incorrect attachment to the house

• Material substituted for thinner gauge

In some cases, a permit is obtained but the structure is not built according to the approved plans.

If construction does not match the engineering tables and approved drawings, it is not compliant — even if it passed inspection.

Homeowners should confirm:

• Permit was issued

• Engineering matches city wind requirements

• Dimensions match approved plans

• Installed materials match specified thickness

• Final inspection was signed off

Permits exist to verify structural safety and protect long-term property value.

The Simple Structural Flow

1. Identify structure type

2. Confirm wind and live load requirements

3. Confirm dimensions (width × projection × height)

4. Select rafter span

5. Select beam and post spacing

6. Size footings

7. Apply correct metal gauge

8. Include connection details

Everything in the packet supports those steps.

Engineering packets look complex because they are written for plan reviewers. But they answer one question:

Can this structure safely resist gravity, wind, uplift, and time in your city?

That is the entire purpose.