Roof Underlayment in Oklahoma - What It Does Under Your Shingles

Roof underlayment is the layer that sits between your roof deck and your shingles. It is the secondary water barrier: when wind lifts a shingle or rain gets driven sideways under an edge, the underlayment is what keeps that water off the wood and out of your attic.

On an Oklahoma roof, that job matters more than most homeowners realize. CRE Roofing puts down new synthetic underlayment on every full replacement, and below is why that layer deserves a line on your estimate.

What underlayment actually does

Shingles are the first line of defense, but they are not a sealed surface. They overlap, they have seams, and they depend on an adhesive strip to stay down in wind. Underlayment covers the whole deck underneath them so that:

• Wind-driven rain that gets past a lifted or creased shingle has somewhere to run off instead of soaking the decking
• The deck stays protected during the install itself, between tear-off and shingles
• Small gaps around a shingle repair do not turn straight into a ceiling stain

Think of shingles as the roof you see and underlayment as the roof that saves you when the visible one has a bad day.

Why it matters in Oklahoma weather

Oklahoma roofs fail from weather far more often than from quiet old age. Wind lifts shingles after storms. Hail fractures shingle mats. A creased shingle breaks its seal and will not re-seal, even when it lies back down looking normal.

Every one of those failures puts more load on the underlayment. A roof with a sound secondary barrier can ride out a lifted shingle until it is repaired. A roof with worn-out or missing underlayment leaks right away.

Felt vs synthetic underlayment

There are two broad families you will hear about.

Felt underlayment - often called roofing felt, roofing paper or "tar paper" - is the older standard. It is an asphalt-saturated mat that comes in rolls. It has been used on roofs for generations.

Synthetic underlayment is a newer, polymer-based sheet. In general it is lighter, more tear-resistant during installation, and holds up better if it is exposed for a while before shingles go on.

CRE uses synthetic underlayment on full replacements. It is listed on our roof replacement page as one of the standard line items, alongside new drip edge, flashing, ventilation and pipe boots.

The shortcut to watch for

One of the shortcuts we see on roofs we are called out to fix is old felt left in place instead of new underlayment going down. The shingles on top are new, so the job looks finished. Underneath, a layer that has already spent years in the Oklahoma sun is now expected to last another twenty.

The same goes for re-used pipe boots, vents and flashing. When a bid comes in well under the others, it is usually a shorter list of new parts, not better buying. Ask every roofer bidding your job, in writing, whether the underlayment, boots, vents and flashing are new.

Can underlayment be replaced without a new roof?

Not really. Underlayment sits under the shingles, so replacing it across the roof means removing the shingles - which is a replacement. During a localized roof repair, we do repair or rebuild the underlayment and decking in the area where water has already gotten through, then confirm it is dry.

Signs the underlayment may be failing include leaks with no obvious shingle damage above them, soft or stained decking seen from the attic, and stains that keep coming back after a surface repair.

Common questions

Is underlayment required under shingles? It is a standard part of a properly built shingle roof. A complete replacement includes it as part of the full system.

Is synthetic better than felt? Synthetic is generally lighter and more tear-resistant and is what we install on replacements. The bigger issue is whether the underlayment is new at all.

Does underlayment stop hail damage? No. Hail damages the shingle mat. Underlayment helps keep water out when the shingles above it have been compromised.

Can I see the underlayment on my roof? Usually only from the attic at the deck edge, or during tear-off. On a CRE replacement we photograph the decking once the old roof is off.

Get your roof checked

If you are not sure what is under your shingles, a free CRE Roofing inspection will tell you what we can see and what it means. Book through our contact page. CRE Roofing is a family-owned Warr Acres contractor.