Insurers rate a roof on four attributes: the covering material, the shape of the roof, its age and how securely it is attached to the building. The material is the one owners think of as the roof type, and it matters to an underwriter for two separate reasons. It predicts how the roof will behave in wind, hail and fire, and it sets what replacing it will cost.
Those two pull in opposite directions often enough to be confusing. A material can be more resistant to damage and more expensive to replace at the same time, and where a particular carrier lands depends on which risk dominates in your area.
The four attributes an underwriter records
| Attribute | What it tells the insurer |
|---|---|
| Covering material | Likely performance in wind, hail and fire, and replacement cost |
| Shape | How wind loads the roof. A simple hip behaves differently from a complex gable |
| Age | How much service life is left, and often whether cover is available at all |
| Attachment | How the covering and the deck are fixed, which decides what wind takes off |
Age is usually the decisive one. A well chosen material on a roof at the end of its life is still a roof at the end of its life, which is why carriers ask the installation year before they ask anything else. Roof age and home insurance covers how that question is used.
How the common coverings are viewed
- Asphalt shingle. The default, widely accepted, with performance depending heavily on the product and the installation. Impact rated versions are treated more favorably by many carriers.
- Metal. Durable, noncombustible and long lived. Panel systems resist wind well when properly attached, and hail damage is often cosmetic rather than functional, which brings cosmetic damage exclusions into play.
- Tile and slate. Long lived, fire and wind resistant, and substantially more expensive to replace. The underlayment beneath sets the real age.
- Wood shake and shingle. The hardest to insure, because of fire. Often declined, and often restricted by local code.
- Low slope membranes. Rated on membrane type, age and drainage. Some residential carriers limit or decline them.
- Built up and modified bitumen. Mostly commercial, assessed on age, condition and the state of the drainage.
What the ratings and tests actually describe
Three independent classifications sit behind a lot of underwriting language, and each describes a laboratory result on new material rather than a guarantee.
- Impact resistance. A standard test drops steel balls onto samples from set heights, sorting products into four classes. Class 4 is the most resistant.
- Wind resistance. Products carry tested wind speed ratings, which depend as much on the fixing pattern and the deck as on the material.
- Fire classification. Coverings are rated A, B or C for external fire exposure, with A the most resistant. This is what makes wood shake difficult.
The common thread is that all three depend on installation. A highly rated product fixed badly to a poor deck does not perform to its rating, which is why attachment is a separate underwriting question and why a wind mitigation inspection records fixings rather than materials.
It is not only about the premium
Roof type influences three different things, and owners usually only hear about the first.
- Price. Through the rating factors above, and through any credits a carrier offers for rated products.
- Eligibility. Whether a carrier will write the policy at all. Wood shake and largely flat residential roofs are the common sticking points.
- How a claim settles. Older roofs and some materials are more likely to be written on an actual cash value or a schedule basis rather than replacement cost, and cosmetic damage exclusions appear most often on metal. Actual cash value against replacement cost explains what that difference is worth.
What to document, whatever the roof is
Keep the covering type and product name, the installation date, the contractor, the permit, any product rating documentation and the warranty. On a tile roof add the underlayment date. On a low slope roof add the membrane type and thickness.
That file answers most underwriting questions without argument, and it is what a condition report is measured against later. A roof certification inspection covers what an insurer usually wants when they ask for evidence rather than an answer.
Where to go next
If you are weighing a replacement and want to know what a new roof changes, does a new roof lower your home insurance covers the question directly. If a carrier has already raised the roof as a problem, start with roof age and home insurance, because age is usually what sits behind it.
Common questions
How does an insurer know what my roof is made of?
From what you tell them, from public records and increasingly from imagery. Application questions ask for the covering type and the year it was installed, property data vendors supply roof attributes from aerial and satellite photography, and some carriers order an inspection before or shortly after binding the policy.
- Your own answers on the application are the starting point
- Permit and tax records may record a reroof
- Aerial imagery is widely used to read covering and shape
- Carriers may order an inspection at new business or renewal
- An error is worth correcting rather than leaving
Two consequences follow. First, answering accurately matters, because a misstatement about the roof is a misstatement on the application and that is the sort of thing a carrier revisits when a claim is large. Second, the data they hold may be wrong, since imagery can misread a covering and records can miss a reroof done without a permit. If a quote or a renewal appears to be priced on the wrong roof, documentation fixes it. [Should you tell your insurer about a new roof](/articles/premiums/) covers how to get a replacement on the record.
What does a Class 4 impact rating mean?
It is the top category in a standard laboratory test where steel balls are dropped onto a roofing sample from set heights, and a product passes by not cracking or splitting. It describes resistance to simulated hail impact, measured in a laboratory, on new material.
- Four classes exist, with Class 4 the most resistant
- The test drops steel balls from specified heights
- It is an impact test, not a hail forecast
- Ratings apply to new material, not aged material
- Several covering types are available Class 4 rated
The rating is useful and it is not a promise. A rated product resists impact better than an unrated one, which is why many carriers and some states recognize it, but a roof still ages, and a severe enough stone will still mark it. Where it changes the economics most is on a building in a hail prone area facing repeated claims. Ask your carrier how they treat the rating where you live, and keep the product documentation, since the benefit usually depends on being able to prove what is up there.
Does a tile or slate roof cost more to insure?
It can cut both ways, and the two forces work against each other. Tile and slate resist wind and fire well and last a long time, which an underwriter likes. They also cost much more to replace and need specialist labor, which raises the exposure on any claim that does occur.
- Both materials are durable and long lived
- Replacement cost per area is considerably higher
- Matching discontinued profiles can be difficult
- Underlayment life, not tile life, sets roof age
- The dwelling replacement cost rises with the material
The point owners most often miss is that a tile roof's age is the age of the underlayment beneath, not of the tile. A hundred year old clay tile can sit on an underlayment near the end of its service life, and a carrier asking how old the roof is wants the second answer. Documenting the underlayment replacement date, with evidence, is worth doing on any tile roof. [Roof age and home insurance](/articles/roof-age/) covers how age questions are usually framed.
Does a flat roof affect home insurance?
Often, yes. A low slope roof drains more slowly, shows ponding, and relies on a continuous membrane rather than on overlapping pieces, so some carriers rate it differently and a few decline a largely flat residential roof outright. On commercial property the system type is a standard underwriting question.
- Drainage and ponding are the underwriting concerns
- Membrane type and age are both asked about
- Some residential carriers limit or decline flat roofs
- Partial flat areas are usually treated separately
- Commercial policies may carry roof surfacing limits
Where a house has a flat section over an extension or a porch, expect it to be asked about separately rather than averaged into the main roof. Keep the membrane type, installation date and any warranty with the property papers, because those three answers settle most of the question. On commercial property the equivalent issue is a roof surfacing limitation, which restricts how the roof itself is settled. [Commercial property insurance and your roof](/articles/commercial/) covers that clause.
Does wood shake roofing affect insurability?
More than any other covering, and the issue is fire rather than water. Untreated wood shakes and shingles burn, so many carriers decline them, many jurisdictions restrict them in wildfire areas, and policies that are offered may be priced well above the equivalent on a noncombustible roof.
- Fire performance is the main underwriting objection
- Treated products are rated better than untreated ones
- Local codes may prohibit replacement in kind
- Availability of cover varies sharply by area
- Replacing the covering can restore eligibility
If a policy has been declined or non renewed over a shake roof, the practical route back is usually replacing the covering with something rated for the area rather than appealing the decision. Check what the local code requires before choosing, since some jurisdictions no longer permit replacement in kind. [Homeowners insurance cancelled because of the roof](/articles/homeowners-insurance-cancelled-because-of-roof/) sets out the notice rules and what options exist while cover is being arranged.