Three-Tab Roof: When to Repair It and When the Spec Changes

If your house still has three-tab shingles and you are weighing one more repair against a fuller job, the decision mostly turns on three things: what the shingle actually is, what the paper band on the bundle says about it, and what the roof has already been through. This page covers the material and spec side for a St. Louis house. It does not tell you what your roof is worth or how an insurer will read a repair, since those are separate questions with their own rules.

Material and spec

What a three-tab shingle is

A three-tab shingle is a single layer of asphalt-saturated mat, cut so that each piece looks like three smaller tabs laid in a row. It was the standard asphalt shingle for a long time, and many older houses in St. Louis County still carry one. A laminated shingle, often sold as architectural, bonds two layers together so the edge looks uneven and the shingle is heavier and thicker. The two products do not swap cleanly on a repair. Their exposure, their nailing and their weight at the eave all differ, so a laminated shingle dropped into a three-tab roof can look wrong and sit wrong at the same time.

Read the wrapper before you trust a sample

Every bundle carries a paper band with the product name, the colour, the bundle count and usually a wind classification. Ask for the wrapper, or ask the supplier for the spec sheet that matches the bundle number. The wind rating you want to see is referenced to ASTM D3161 or ASTM D7158, the two test methods used for asphalt shingle wind resistance. A label that names a class without naming the test is not enough on its own, because the two methods are run differently and their classes do not map one to one.

Keep the wrapper, or photograph the band before it goes in the dumpster. If you later need to show what was installed, the band is the record that ties the shingle to a product name and colour. Keys documents damage, puts a written scope with photos and measurements in the homeowner's hands, and attends as the contractor while the homeowner deals with their own insurer, so the paper trail belongs with the homeowner as well.

Match exposure before colour

Exposure is the part of each shingle that shows once it is laid, measured from one course to the next. A three-tab repair that matches in colour can still be off by an inch of exposure, and the eye picks that up along a ridge line before it picks up the colour. Measure a few courses on the roof at a clean edge, not at the eave, and write the number down. Then ask whether the product still in the supplier's stock uses that exposure. Three-tab colours come and go in supplier catalogues, so a colour that matched a few years ago may no longer be stocked, and a substitute with a different exposure will show as a stripe across the slope.

Test what is already on the roof

Before a repair is priced, the existing shingles need a plain check. Lift a tab gently at the edge and see whether it bends or cracks. Shingles that crack when lifted are brittle, and brittle shingles often break again when a new piece is slid in beside them. Look at the granules in the gutter and along the lowest course. Bare mat showing in a band across the slope suggests the top surface is worn, and a repair set beside worn shingles will age faster than the new piece. Look for curl and cup as well. A roof where many tabs lift in a pattern points to a sealing or wind problem across the slope, not a few isolated failures.

When a repair stops making sense

There is no single age at which a three-tab roof stops being worth repairing, because the condition of the shingles matters more than the calendar. Still, roofers in this area often start asking the question once a three-tab roof has passed its second or third decade, especially if the shingles are brittle, the colour is no longer stocked, and the damage is spread across several slopes. A few torn tabs after a wind event is usually a small repair. Ten torn tabs on the south slope, brittle tabs on the north slope, and a colour that no supplier can source is a different decision.

A repair is also a poor fit when the roof already has two layers. A patch laid over a roof that needs a proper tear-off can hide the real condition under the first layer. Ask the roofer to count the layers at the edge before you agree to a repair scope, and ask what they found.

What a laminated spec changes

Moving from three-tab to laminated is a spec change, not just a shingle swap. The laminated product is heavier, which matters on an older rafter layout, and it has a different nailing pattern and a different starter detail at the eave. Ask whether the decking and framing were checked for the added weight, and whether the nail count per shingle matches the manufacturer's installation instructions for the laminated product. Keys installs Atlas and Malarkey shingles only, so any laminated line would come from one of those two makers. A roof built for a light single-layer product is often able to carry a laminated shingle, but that should be checked on the roof rather than assumed from a brochure.

What it costs

The shingle is one line on a quote, not the whole price. A repair is priced mostly by the trip to the roof, the number of tabs replaced and the time it takes to match and seal them. A full replacement is priced by the square count, the number of layers to be removed, the underlayment, the flashing and the disposal. A repair on a short run of tabs can cost less than a laminated spec change, but a repair that has to be redone within a year costs more than either. Ask for the repair price and the replacement price on the same written sheet, so the gap between them is visible before you decide.

What to ask

• Which product name, colour and exposure is printed on the bundle, and can I see the wrapper or a photo of the band?
• Which wind classification is printed on the wrapper, and which ASTM test does it cite?
• Is this colour and exposure still stocked by the supplier, and if not, what changes on the roof?
• How many layers are on this roof, and where did you count them?
• Will you test the existing shingles for flexibility before any new pieces are laid?
• If we go laminated, has the decking and framing been checked for the added weight?
• Is the repair price and the replacement price on the same written sheet?

If you have the bundle label or a photo of the roof, the Keys office at (314) 220-2333 can talk through the spec question with you before anything is scheduled.