Boral Underlayment & Deck Repair in San Antonio, TX

Boral Underlayment & Deck Repair: The San Antonio Owner’s Guide

Boral underlayment and deck repair in San Antonio typically runs $340-$780 installed, depending on how much decking needs replacement and whether we’re working with Boral’s Stone Coated Steel or concrete tile systems. We stock Boral-compatible underlayment on every truck, and most deck repairs are completed same day. You’ll usually discover the problem after a hard rain, when water spots appear on your ceiling or you notice a soft spot when walking the roof perimeter - signs that the underlayment has degraded beneath the primary roofing material, or that decking has rotted where moisture pooled.

Call (833) 756-5022

San Antonio’s combination of intense UV exposure, sudden summer downpours, and occasional hail creates a specific wear pattern on Boral systems. The underlayment takes the brunt when wind-driven rain finds its way past tile edges or stone-coated overlaps. Cecil Hargrove has walked enough of these roofs to know that catching it early means replacing a few sheets of decking and a run of underlayment. Waiting means fascia damage, insulation saturation, and a much bigger number.

Which Boral Models This Applies To

Boral Roofing produces two primary systems in the San Antonio market: Stone Coated Steel (the Boral Steel line, formerly Gerard) and concrete roof tiles. The underlayment and decking requirements differ between them, and mixing specs is where we’ve seen other contractors create problems.

Boral Stone Coated Steel uses a 30-pound felt minimum or synthetic underlayment rated to 250°F, because the metal substrate transfers heat differently than concrete. The concrete tile systems call for a two-layer approach in valleys and penetrations: a base underlayment plus a self-adhering membrane like Boral’s specified ice-and-water shield equivalent. We’ve found the label on existing underlayment by lifting a corner tile at the eave - Boral-authorized installers are required to document the underlayment type on the original permit, and that paperwork is usually available through the City of San Antonio Development Services Department if you’re unsure what was installed originally.

Decking beneath Boral systems is typically 7/16″ OSB minimum on trusses spaced 24″ on center for steel, or 15/32″ plywood for concrete tile due to the weight load. We carry both specs on our trucks, and we won’t substitute. An aftermarket underlayment can perform as well as OEM if it meets Boral’s published permeability and temperature ratings - we use Atlas StormMaster or CertainTeed DiamondDeck when the homeowner prefers, but we document the spec so there’s no warranty confusion later.

Signs Your Boral Underlayment & Deck Repair Is Failing

• Water stains on interior ceilings, especially after wind-driven rain. Boral’s tile and steel profiles overlap, but San Antonio’s spring storms hit at angles that force water past the primary defense. When underlayment cracks or loses adhesion at laps, the decking absorbs moisture and the ceiling below tells the story. We see this most often in homes north of Loop 1604 where 2016 and 2021 hail events compromised the system.
• Soft or spongy spots when accessing the roof for gutter cleaning. OSB decking loses structural integrity when moisture content exceeds 19 percent. If you feel give beneath your foot near the eave or valley, the decking has likely delaminated. This is not a surface issue - the underlayment has failed somewhere uphill and water has traveled.
• Granule or tile debris accumulating in gutters with no visible roof damage. Boral Stone Coated Steel sheds granules when the underlayment beneath has allowed moisture to reach the metal substrate, triggering corrosion that pushes coating off. Concrete tiles show efflorescence - white mineral deposits - when trapped moisture wicks through. Both point to underlayment nearing end of life.
• Mold or mildew odor in the attic during summer months. San Antonio’s humidity stays above 60 percent from May through October. Failed underlayment becomes a one-way valve: moisture enters, heat prevents escape. We document attic conditions with photos during every inspection, and we’ve found mold on decking that looked sound from outside.
• Visible underlayment at eaves or ridges that has become brittle or torn. UV exposure degrades exposed underlayment in 18-36 months in South Texas. On Boral systems, this usually means inadequate overhang coverage or wind uplift that shifted tiles. The underlayment was never meant to be a surface material, and once it’s exposed, replacement is imminent.

Replacement Cost & What’s Included

What drives the range: accessibility (steep pitches or multi-story homes in Alamo Heights or Terrell Hills require additional safety rigging), the extent of decking replacement, and whether we’re matching existing Boral tile or steel that has been discontinued. We quote the full number upfront - the price we quote is the price you pay. Our 90-Day Done Right Promise covers the workmanship, and we use only underlayment that meets or exceeds Boral’s published specifications. No substitutions without your written approval.

DIY or Call Us?

There’s a safe middle ground here, and then there’s the point where you need a crew.

What you can check safely from the ground or a sturdy ladder: binoculars inspection of exposed underlayment at eaves, attic access to look for moisture stains on the underside of decking, and a flashlight check for mold. Document what you see with photos - we use homeowner photos to prioritize our response when storms back up our schedule.

What you should not attempt: lifting Boral tiles or steel panels to inspect beneath them, walking a roof with suspected decking damage, or handling underlayment removal on slopes steeper than 4:12. The tiles are heavy and brittle; the steel edges are sharp; and compromised decking won’t hold a fall arrest. We’ve been called to jobs where a homeowner’s foot went through rotted OSB - the medical bill dwarfed the repair.

We’re not affiliated with Boral Roofing, but we’re authorized to install their systems and we carry the compatible materials. If you’re seeing any of the symptoms above, call (833) 756-5022. A live person answers, and we’ll get a technician out with a truck stocked for the repair.

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