Drone view of a completed tile lift and relay by GAX Roofing in Fontana, CA

Homeowner Guide

How to Read a
Roof Inspection

A roof report on a home sale mixes three things: what the inspector saw, what they couldn't see, and what they think it means. Here's how to sort them, before you decide anything.

Get a Free Estimate →

✓ C39 Licensed & Insured

◈ Free In-Home Estimates

⌂ Owner Runs Every Job

◐ Se Habla Espanol

Start here

The Short Answer

Sort every line of the report into what was seen, what couldn't be seen, and what someone thinks it means. A visual inspection can tell you a lot about the surface and very little for certain about the deck and the underlayment under it, so treat any number of years left as an opinion, not a measurement. Then turn the findings into a short list: what needs work now, what to settle before you close, what to budget for, and what's routine.

A useful report has

Every roof section named, including the garage, patio covers and additions
Dated photos, each tied to a location
What was looked at and what wasn't, in plain words
Findings written as what was seen
Recommendations kept separate from findings
Who wrote it, and their license

Read it twice when you see

A remaining-life number with no explanation of how it was reached
"Roof certified" with no term, scope or warranty attached
No photos, or photos with no locations
A finding that jumps straight to a price
A report that never mentions the attic

Step 1

What a Visual Inspection Can and Can't Tell You

California law defines a home inspection on a sale as a noninvasive physical examination meant to find material defects: problems that significantly affect a home's value, desirability, habitability or safety. Noninvasive is the key word. Nobody lifts the roof to look.

What it can show

The covering from above or from the ground: broken or slipped tile, worn or lifted shingles, standing water on a flat roof, flashing, vents, gutters and drainage. From the attic: staining, daylight and the underside of the deck.

What it can't confirm

The underlayment under the tile, the weather side of the deck, how many layers are on the house without looking at the edge, and how the tile was fastened. Those take lifting material, or the tear-off itself.

Instruments point, people confirm

A drone or a thermal camera gives you a theory and a place to look. A cold spot can be water, a draft, missing insulation or a duct. The attic, or lifting material, confirms it.

At GAXOur own inspection checklist says it plainly: underlayment where visible, deck condition visible from above. When a buyer wants to know what's behind a fresh coat of ceiling paint, we bring the thermal camera, and an infrared image on its own is a lead, not a diagnosis.

Thermal image of a ceiling showing a cold wet area during a GAX Roofing leak inspection in Fontana — Fontana: the camera found a cold area. The attic confirmed it was water.

Thermal image of attic framing tracing the wet path of a roof leak in Fontana — The same job, tracing the wet path through the framing.

Step 2

Every Roof on the Property

A house with a garage, a patio cover and an addition has more than one roof. A report should name each section and say whether it was inspected.

Name the sections

Main roof, garage, patio cover, additions, detached structures and any flat or low-slope sections, each with its covering and condition.

Where water goes between them

Look for notes on where an upper roof drains onto a lower one and where a wall rises out of a roof. On a leak call, those are the spots we look at first.

A marked-up picture helps

A simple sketch or an aerial with the sections labeled makes every later finding easy to find on the house.

Street view of a two-story Huntington Beach home with the GAX Roofing crew working on the lower patio roof section; the second-story roof above it drains onto this section — Huntington Beach: the second-story roof drains onto the lower section. From the street, nothing looked broken.

Step 3

The Roof Covering

Tile

A few cracked tiles can be swapped. A lot of them, or tile sliding out of line, is a reason to look at what's underneath. From the ground, look for tiles dropped below their line, gaps of shadow or pieces sitting crooked.

Shingles

Pale, shiny patches where the fiberglass mat shows through mean the granules are gone. Curled, cupped or cracked shingles and caps should be noted with their location.

Flat and low-slope roofs

Standing water more than 48 hours after rain is a sign of a drainage problem. Seams and penetrations are where a flat roof opens up.

Coatings

A coating is only for a roof that is still fundamentally sound. If a report recommends one, it should also say the roof under it is sound.

Missing and slipped tiles with exposed underlayment on a Riverside tile roof inspection — Riverside: missing and slipped tile, underlayment exposed.

Step 4

Where the Water Is Managed

Flashing

Flashing is the seal. Caulk smeared over a gap is not flashing, it's a delay. Nail heads through the face of the metal are a shortcut that leaks later.

Valleys

A valley needs an open channel. Tile run too far into it turns it into a dam.

Penetrations

Every pipe, vent, skylight and solar mount needs its own flashing. On tile, that's one at the tile and another at the deck.

Edges and drainage

Drip edge at the eaves, gutters that are attached, and downspouts that move the water away from the house.

Counter flashing face-nailed flat against a brick chimney with exposed fastener heads, found on an inspection — Counter flashing face-nailed against a chimney, nail heads exposed.

Step 5

Attic and Interior Evidence

The stain is rarely right under the leak. Water gets in at one point and travels along the underlayment or the framing before it shows.

What the report should note

Staining on the rafters and the underside of the deck, daylight, soft or sagging spots, and wet or stained insulation, each with a location.

Fresh paint

A freshly painted ceiling under a roof with a history is worth a question. A thermal scan can show moisture paint hides, and the attic confirms it.

A stain is not a finding of rot

Old staining on solid wood is a record of a past leak, not proof the wood failed. Someone has to check it.

Ventilation

Air needs a way in low, at the eaves, and a way out high. The report should say what vents the attic has.

Dark water staining along a roof rafter and into the insulation, found during an attic inspection in Azusa — Azusa: staining along a rafter and into the insulation, seen from the attic.

Bathroom ceiling with a visible stain beside its thermal frame showing the cold wet area is larger than the stain — The stain you can see is smaller than the wet area the camera finds.

Step 6

Hidden Conditions

The deck

The attic side and the weather side of the deck are two different worlds. Nobody knows the weather side until the old roof is off.

The underlayment under tile

An honest tile inspection looks under the tile, not just at it. Lifting a few tiles to look at the underlayment is the only way to see it.

Layers

There's no way to know how many layers are on a house without somebody looking at the edge of it, lifting something, or checking from the attic. You can't inspect a deck through two roofs.

Fastening

On older tile roofs, how the tile was fastened matters. Tile sliding out of line can point to tile that was only spot nailed.

Split underlayment under intact concrete tile found during a tile roof leak repair in Corona — Corona: the tile looked fine. The underlayment under it had split open along the transition.

Rake edge of a Highland, CA roof during a GAX Roofing inspection, showing several layers of old roofing stacked at the edge — Highland: several layers, visible only at the edge.

Step 7

Read the Language

Most confusion in a roof report comes from mixing different kinds of statements. Here's how to tell them apart.

What the report says	What kind of statement it is	What to do with it
"Three cracked tiles on the north slope above the garage, photo 12"	An observed fact, with a location	Useful as written. Get it priced or monitored.
"Roof shows signs of wear"	A vague observation	Ask where, and what was seen
"Likely caused by foot traffic"	A likely cause, which is an opinion	Fine, as long as it's labeled as one
"Underlayment not visible, not evaluated"	A limitation	This is the part that may need lifting material
"Recommend evaluation by a licensed roofing contractor"	A recommendation	Get it done while you still have time to act on it
"Approximately 5 years of remaining life"	An estimate of the future	Ask how it was reached. The surface can't show the deck or the underlayment.
"Roof certified for 2 years"	A promise with written terms	Read the terms: what's covered, for how long, and who pays if it leaks

One vague line, made useful. Vague: "Some cracked tiles noted." Useful: "Four cracked and two slipped tiles on the west slope above the patio cover, photos 8 to 10. Underlayment under them not visible."

Step 8

Sort the Findings

Put every finding in one of four groups. It turns a long report into a short to-do list.

Urgent

Now

Active leaks, open areas, anything letting water into the house.

Before you close

During the sale

Findings you want repaired, priced or looked at more closely before you commit.

Budget soon

The next year or two

Wear that isn't leaking yet: tired pipe seals, a crowded valley, cracked caps.

Routine

Ongoing

Maintenance: gutters, debris, a check before the rains. Our maintenance calendar covers it.

Step 9

When to Ask for More

Repair pricing

When a finding needs work, get a written price from a licensed roofer, with the products named.

Lifting material

When the report says the underlayment or the deck wasn't visible and the roof has a history, ask a roofer to lift a few tiles or check the edge for layers.

Permit history

Ask the building department for the address whether there's a permit on record for the roof.

A second opinion

A second opinion on a leak that keeps coming back should use instruments, not just eyes.

Licenses

Check the license of whoever gives you a roof opinion on the CSLB site. Home inspectors aren't exempt from California's contractor licensing law, and the law treats it as an unfair business practice for a home inspector to offer repairs, for an extra fee, on a home they reported on in the past 12 months.

The package

What a Useful Report Package Contains

Whether it comes from a home inspector or a roofer, this is what makes a roof report usable later, in the sale and after it.

The date of the inspection and who did it, with their license number
Every roof section named, and which ones were inspected
Dated photos, each with a location
What wasn't inspected and why: access, weather, panels or safety
Findings written as what was seen
Recommendations and estimates kept separate from the findings
Any certification or warranty, with its written terms

At GAXOur inspection reports include photos, a description of what we found and our assessment as a C-39 licensed contractor, usually within 24 to 48 hours. The report is free when we do the repair or replacement, and a separate service when you only need the report.

Questions

Frequently Asked

Can a roof inspection tell me how many years my roof has left?

Not with certainty. A visual inspection sees the surface, and the deck and underlayment under it aren't visible without lifting material. Treat any remaining-life number as an opinion, and ask how it was reached.

What is a roof certification in California?

In the Business and Professions Code, it's a written statement by a licensed C-39 roofing contractor who inspected the roof, made any needed repairs, and warrants that the roof is free of leaks when the certification is issued and should perform as designed for the term it states. Read what it covers, for how long, and who pays if it leaks. We write roof certifications only on roofs we've worked on.

Can the home inspector also repair the roof?

California law treats it as an unfair business practice for a home inspector to offer repairs, for an extra fee, on a home they reported on in the past 12 months, with limited exceptions. Get repair pricing from a licensed roofer.

Is a drone or thermal scan enough to know if a roof leaks?

It's a lead, not a diagnosis. A cold spot can be water, a draft, missing insulation or a duct. The attic, or lifting material, confirms it.

Should I get a roofer's inspection on top of the home inspection?

If the home inspection recommends evaluation by a roofer, or the roof has a history of leaks, yes. A licensed roofer can price the repairs and, where needed, lift material to see what the home inspection couldn't.

What should a roof inspection report include?

The date and who did it, every roof section, dated photos with locations, what wasn't inspected and why, findings written as what was seen, and recommendations kept separate from the findings.

Buying or selling and the roof report raised questions? We'll look at the roof, tell you what we can see and what we can't, and put it in writing. We do four kinds of roofs: asphalt shingle roofs, tile replacement with new tile, tile lift and relay, and flat roofs, across the Inland Empire.