How to measure a roof online, free, from your desk

To measure a roof online for free, open the address in RoofStruct, trace the roof on satellite imagery, label every edge, set the pitch and export the PDF. It's free, unlimited self-serve measuring and PDF reports, no card, and a simple roof fits in one sitting at your desk.

This is the short version. For the long walk-through with every edge type and the pitch math in full, read how to measure a roof from satellite imagery.

What you need#

• An address. That's the whole site visit. The house has to be visible from above, which rules out a roof buried under a canopy.
• A pitch, or a way to get one. Satellite imagery looks straight down, so it can't show rise over run. Bring the pitch from a past job on the street, the homeowner's paperwork, or the free pitch finder.
• One sitting for a simple gable. A cut-up roof with dormers, a few valleys and a porch tie-in takes longer. Budget for it before you promise a number by tonight.

The steps, from address to PDF#

1. Open the address. Start a new measurement, search the address, center the roof and zoom until it fills the frame. What you frame is what you measure. Satellite imagery sets its own scale.
2. Trace the outline. Pick Draw Roof and click each corner of the roof at the drip edge, all the way around, then click your first point again to close the shape.
3. Split it into facets. With Draw Roof still active, click a point on the outline, click along the ridge, hip or valley, and click the outline again. Repeat until every plane is its own facet.
4. Label every edge. Click an edge and a card asks "What is this edge?" Pick eave, rake, ridge, hip, valley or one of the other types, 12 in all. Nothing is named for you, and every foot of drip edge and ridge cap in the report comes from these labels.
5. Watch the counter. Edges labeled X of Y sits in the Layers tab. Keep going until it reads All edges labeled.
6. Set pitch and waste. Open the Setup tab, set the predominant pitch, then select any facet that runs steeper or flatter and give it its own. Set your waste in the same tab.
7. Check the totals. If two facets overlap, a notice tells you about how much area is counted twice. Fix the shapes, don't export around it.
8. Export the PDF. Hit Export. If any facet still has no pitch, the dialog warns that its area is counted flat. Go back and set it, then download the PDF.

A worked example: 44 × 36 gable at 5/12#

Say the house is a plain gable, 44 ft along the ridge and 36 ft eave to eave at the drip edge, at a 5/12 pitch.

• Plan area: 44 × 36 = 1,584 sq ft.
• Pitch factor for 5/12: the slope runs 13 for every 12 across, so 13 ÷ 12 = 1.083.
• True area: 1,584 × 13 ÷ 12 = 1,716 sq ft, or 17.16 squares.
• With 10% waste: 17.16 × 1.10 = 18.88, so you order 19 squares.
• Eaves: 2 × 44 = 88 ft. Rakes: each runs 18 ft across, times 1.083 = 19.5 ft, and there are four, so 78 ft. Ridge: 44 ft.
• Drip edge on eaves and rakes: 88 + 78 = 166 ft.

Now leave the pitch off. The roof gets counted flat at 1,584 sq ft, which is 132 sq ft short, more than a square and a quarter before waste. That's the shortfall you discover with the crew on the roof.

What you get#

The export is the full PDF with RoofStruct branding, the same report on every plan:

• A roof summary page: true area, squares, pitch and the roof's totals at a glance
• A length diagram with every edge measured, plus totals by edge type
• A pitch and direction diagram and an area diagram, facet by facet
• Area broken out by pitch

That covers a takeoff, a supplier quote or a talk at the homeowner's table. For the line between free and paid, item by item, see what free satellite roof measurement gets you.

The limits of measuring from your desk#

These come with looking at a roof from above. They aren't quirks of one tool.

• Trees. A canopy over the eave hides where the roof ends. If you can't see the edge, you're guessing at it.
• Shadows. The dark side of a hip roof swallows the line where a hip meets a valley.
• No pitch from above. The image gives you the footprint and the line lengths. Rise over run is always something you bring.
• Old imagery. The photo can predate an addition, a new dormer or a tear-off that changed the profile. If the drive-by or the homeowner's photos don't match the screen, believe the house.
• Your own upload needs one known length. Working from your own drone or phone photo? Use Set Scale on one distance you've taped, like a garage door or a ridge you've measured. Without it, every number on the PDF is wrong by the same unknown factor.

Where you trip#

• Tracing to the wall. Satellite imagery shows the roof, and the roof ends at the drip edge, not the siding. Tracing the wall line drops your overhang off every eave and rake.
• One giant outline. Skip the facets and you get a total area with no per-slope data, and your valleys and hips never get a length.
• A counter short of green. Unlabeled edges mean short line footage, so the drip edge and cap on your order are short too.
• Zero waste. A clean measurement still short-orders the job if waste sits at zero.

FAQ#

Can I measure a roof online for free?#

Yes. RoofStruct gives you free, unlimited self-serve measuring and PDF reports, no card. You trace on satellite imagery or on your own drone or phone photo and export the full PDF every time.

Do I need the roof pitch before I start?#

No. Trace and label first. You need a pitch before you export, because a facet with no pitch is counted flat and comes up short on a pitched roof.

Can I measure from my own drone or phone photo?#

Yes. Upload it, then use Set Scale on one length you know. The tracing, labeling and export work the same as on satellite imagery.

Is a desk measurement good enough to order materials from?#

It's as good as the image and the pitch you give it. On a clear roof with a pitch you trust, check the PDF totals against your own arithmetic and order from it. Under trees or deep shadow, get eyes on the roof before you commit to a delivery.