What Is Timberline UHDZ with UltraMat?

A premium laminate asphalt shingle, and the part that actually changed is the mat inside it. UltraMat is GAF’s high-performance fibreglass mat, and shingles sold in packages bearing the UltraMat logo and the UL 2218 Class 4 Classification statement pass the impact test at Class 4, the highest of the four. That qualifier is not fine print and it is the single most misquoted thing about this product: the rating belongs to the packaging you can point at, not to the product name. Arrowhead Roofing has installed GAF systems on northeast Oklahoma roofs since 1987, and in a market that took hail on more days than most people realise, the mat is the part worth understanding.

Note: this is a general description of a manufacturer’s product as published in August 2026. Specifications, ratings and warranty terms are GAF’s and they change. Verify the current specification sheet and the packaging for the product actually going on your roof, and read the limited warranty rather than any summary of it, including this one.

The published specification, taken from GAF’s own sheet rather than from a summary.

The Short Answer

Most asphalt shingles are built on a fibreglass mat, and the mat is what carries the shingle when something hits it. UHDZ is a heavier laminate built on a stronger mat, and the impact rating follows from that.

Andy Anderson at Arrowhead describes it the way a homeowner standing in a driveway actually experiences it: heavier than a standard architectural shingle, with a dual shadow line so it reads as more three dimensional, and it “looks more like wood shake shingles.”

Both halves matter here. It is a hail product and it is also a better looking roof, and in this market people buy it for both reasons.

The Class 4 Claim, Stated Precisely

This is the section this page exists for, because the imprecise version of it is everywhere.

UL 2218 is an impact resistance test. A steel ball is dropped onto the material from a set height, twice on the same spot, and the sample is examined for cracking on the back side. Class 4 is the highest of four classes and corresponds to the largest ball.

Here is the precision that matters. Only shingles sold in packages bearing the UltraMat high-performance mat logo and the UL 2218 Class 4 Classification statement are rated for Class 4 impact resistance. The rating attaches to the classified product in its packaging. A shingle described to you as Class 4 in conversation is a claim; a package with the statement printed on it is a fact, and you are entitled to see one.

The photograph at the top of this page is a pallet in our own yard, and it is there so you know what you are looking for. The Class 4 shield and the UltraMat badge sit on the same face of the wrapper. If somebody is putting an impact rated roof on your house, ask them to show you that face before the bundles go up the ladder. It takes ten seconds and it is the only version of this claim you can check yourself.

There is a second logo doing a second job. The StainGuard Plus PRO algae coverage also applies only to shingles sold in packages bearing that logo. Two qualifiers, two logos, and they are not interchangeable.

And what Class 4 does not mean is worth saying too. It is a laboratory impact classification, not a promise about a specific hailstorm. It does not make a roof hail proof, it does not mean damage cannot occur, and it does not change what a policy covers. Whether hail damaged your roof is still a question somebody answers on the roof: can 3/4 inch hail damage a roof? covers what the local record actually looks like.

The Part Most Contractors Get Wrong

A Class 4 field shingle on a roof capped with an ordinary ridge is not a Class 4 roof, and this is the detail that separates a specification from a sales line.

Hip and ridge cap is a different product from the field shingle, made differently, and it has its own impact classification. For a genuinely Class 4 system the cap has to be rated as well, which means one of GAF’s impact rated caps: TimberTex Premium, TimberCrest Premium SBS-Modified, or Seal-A-Ridge AS SBS-Modified.

Most contractors who install a Class 4 field shingle never think about the ridge. It is a small line item on an estimate and it runs along the most exposed part of the roof.

Wind, and What WindProven Actually Requires

Three separate things get run together here and they are genuinely different.

The wind ratings are product test classifications. UHDZ meets ASTM D7158 at Class H, the uplift force method for shingles that have sealed, and ASTM D3161 at Class F, the fan induced method.

WindProven is a warranty, not a rating. GAF publishes a 15 year WindProven limited wind warranty with no maximum wind speed limitation, and it is conditional: the roof has to be built with GAF starter strips, roof deck protection, ridge cap shingles and leak barrier. Four accessory categories. Leave one out and the coverage is not the one you were told about.

LayerLock is a construction feature. It mechanically fuses the bond between the overlapping layers of the laminate. It is part of why the shingle behaves the way it does; it is not a warranty and it is not a rating.

The practical consequence is that the accessories are part of the product decision rather than an upsell on top of it. A cheaper starter strip is not a cheaper version of the same roof.

How It Goes On

The specification decides what the roof can do. The installation decides whether it does it.

GAF’s standard application for these products is four nails per shingle, and its own installation instructions describe a six nail pattern as the enhanced one. We install six on every roof, on every product, whether or not anything requires it. At 64 pieces per square that is 384 nails where the baseline is 256.

Being accurate about what that does and does not buy: it is the manufacturer’s own enhanced pattern applied everywhere, and it is not a claim that the wind coverage on your particular roof is upgraded by the count. Enhanced wind coverage is tied by GAF to particular products and conditions, and the product’s limited warranty is what governs it.

The fasteners themselves meet the code specification rather than beating it: minimum 1-1/4 inch, penetrating three quarters of an inch into the deck or a minimum of an eighth of an inch through it, 3/8 inch minimum head, 10 to 12 gauge. How many nails per shingle does code require? covers what the code says and where the six nail pattern sits against it.

What Changes the Answer

Three things decide whether this is the right shingle for a particular house.

Whether the house qualifies for the system

The enhanced warranty tiers carry conditions about the accessories used and about the roof itself. Not every house qualifies for every tier, and it is a question to settle before anybody chooses a colour rather than after.

Whether your carrier gives anything for it

Some carriers offer a premium credit for an impact rated roof and some do not. GAF’s own published position is the honest one to repeat: insurance discounts may not be available in your area, and where available they vary. We are not going to publish a percentage, because the figure that circulates in this market has no source we could verify. Ask your carrier, in writing, before you spend anything on the strength of it.

What the roof already needs

A premium shingle on a deck that needs replacing, or over ventilation that does not meet the requirement, is money in the wrong place. The order of operations is deck, ventilation, accessories, then shingle. How much does a new roof cost in the Tulsa area? covers how those pieces stack up.

Why We Can Have This Conversation at All

A mechanism rather than a claim, and it is the reason a premium product turns up in an ordinary conversation here.

Most contractors call a supply house and have job lots delivered to the site. We buy by the truckload, shipped direct to our own yard, and deliver to the job ourselves. That earns better pricing on material, and better pricing on material is what lets a higher specification be on the table instead of out of reach.

Related Questions

How many nails should be in each shingle?

The code sets a specification and the manufacturer sets a pattern, and they are two different things. How many nails per shingle does code require? covers both and where six fits.

How long should a roof like this last here?

Longer than the storm record tends to allow, which is the honest complication. How long does a roof last? covers service life against Tulsa’s actual hail frequency.

Does hail this size really do damage?

Three quarter inch is the most common size at Tulsa addresses, and the answer is more interesting than yes or no. Can 3/4 inch hail damage a roof? covers what the record shows.

See Also

The two answers next to this one are how the shingle is actually fastened down, and what else has to be right before the shingle matters.