Boral Underlayment & Deck Repair Nationwide

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

If you have a Boral roof and the underlayment or decking beneath it has failed, we can match the right part to your model and install it for typically $1,800 to $4,600 in San Jose, depending on how much decking has rotted and how many squares of underlayment need replacing. Most Boral underlayment and deck repairs take one to two days once we’re on site, and we carry Boral-compatible synthetic underlayment plus CDX and OSB decking on our trucks so we’re not running back and forth to a supply yard. The way most San Jose homeowners discover this problem is not from a leak in the living room. It’s usually a tile that’s cracked or shifted after a heavy rain, and when we lift it to reset, the underlayment underneath crumbles in our hands. By that point, water has been working against the deck for a while.

Call (669) 274-0078

If you’re reading this page, you probably already know the gut-punch feeling: the roof itself is solid Boral tile with decades of life left, but the layer protecting your home underneath has quietly given out. That’s the part nobody sees until it’s too late. The good news is this is a repair we do regularly across San Jose, and it does not mean you need a new roof. Greg Holloway has spent years running tile crews in this city, and he’ll tell you the same thing he tells every homeowner: tell me what’s on your roof and I’ll tell you what it needs – straight answer, no guesswork.

Here’s what you need to know about Boral underlayment and deck repair in San Jose, from costs to compatibility to the one thing most people get wrong when they try to patch it themselves.

Which Boral Models This Applies To

Boral roof tile carries a reputation for lasting a long time, but the underlayment beneath it has a shorter service life than the tile itself. That’s true whether you have Boral’s flat-profile concrete tile, their Mission-style “S” tile, or the lightweight profile that was popular on San Jose homes built in the 1990s and early 2000s. The underlayment we install as a replacement is not a Boral-branded product. Boral makes tile, not felt. So the compatibility question is less about matching a “Boral part number” and more about matching the underlayment to the tile profile, the roof pitch, and the way your original installer set the batten system.

What matters for compatibility: the tile’s headlap (how much one tile overlaps the next), the exposure (how much of each tile is visible), and whether your roof uses a batten system with counter battens or direct-to-deck installation. We measure all three before quoting anything. If your home still has the original Boral paperwork, it may list the profile name and installation date, which helps us dial in the right specification. Most of the time, though, the roof tells us everything we need. One gotcha we see regularly in San Jose: original installers in the 80s and early 90s sometimes used 30-pound felt on Boral roofs, which breakdowns faster than modern synthetic underlayment. If that’s what’s under your tile, replacing it with a synthetic rated for tile roofs adds years to the system. Tilehurst Roofing San Jose is an independent service provider, not affiliated with Boral, which means we can choose the underlayment that actually fits your roof rather than whatever a brand rep is pushing this quarter.

Signs Your Boral Underlayment & Deck Repair Is Failing

• Water stains on the ceiling or exterior walls after heavy rain. This means water has already gotten past the underlayment and soaked into the deck or, worse, the framing. The underlayment’s job is to be the waterproof layer, so any interior stain means that layer has already failed somewhere above.
• Cracked, shifted, or “tented” tiles. When decking swells or rots, tiles move. A tile that shifts half an inch tells you the substrate beneath it is no longer stable. We see this often on San Jose homes where the original deck was plywood rather than OSB.
• Granules or dark grit in the gutters. If your underlayment is the old felt type, it sheds small bits as it degrades. When you clean your gutters and find dark, sandy material mixed with debris, it’s often not road dust; it’s your underlayment breaking down.
• Soft spots or sagging anywhere in the roof plane. From the ground, a healthy tile roof has a crisp, even line. If one section dips or looks “wavy,” the deck beneath is compromised. This is not a cosmetic issue, and it gets worse with every rainy season.
• Daylight visible in the attic. On a sunny day, go into your attic and look up. If you see pinpricks of light through the roof deck, you’re also seeing water entry points. This is the clearest sign the deck needs replacement, not just patching.

Replacement Cost & What’s Included

Tile roofs are not like asphalt shingle repairs. You cannot simply nail a patch over bad underlayment and call it done. The tile above the affected area has to come off, the failed underlayment gets stripped, the deck below is inspected and replaced where it’s rotted, fresh underlayment goes down, and then the tile goes back on. In San Jose, the labor range for that process is what drives the price, plus materials.

That price includes removal and resetting of the tile, underlayment replacement, decking repair or replacement as needed, and cleanup with a magnetic sweeper to catch any stray nails or fasteners. You get a written price before we begin – that’s not a policy we have sometimes, it’s every single time. And every repair comes with a written guarantee handed to you before the crew leaves, not mailed later. If the repair fails inside the guarantee period, we come back and correct it at no charge under our 365-Day Done Right Promise. That’s the Kingswell Way: say the price before the work, show up in the window we gave, leave the place cleaner than we found it, put the guarantee in writing, and come back if it fails.

DIY or Call Us?

If you’re comfortable on a ladder, you can safely check a few things: look for shifted tiles from the ground or gutter line, check the attic for daylight, and clean out gutters on a dry day to inspect for the dark grit that signals underlayment breakdown. What you should not do is get on the roof and start pulling tiles. Tile roofs carry real weight, and proper Boral underlayment repair requires removing enough tile to reach the failed layer without cracking the surrounding tiles in the process. One wrong step on a Mission tile can crack $200 worth of material in a second, and if you don’t know how to lap underlayment correctly, you’ll create a bigger leak than the one you started with. We’re not trying to scare you off; we’re telling you what happens to the homeowners who try this and then call us anyway. If you want to know exactly what’s wrong and what it costs to fix, call (669) 274-0078 and we’ll come take a look. The estimate is free.

FAQs

Get Your Free Boral Underlayment & Deck Repair Estimate in San Jose

If your Boral roof is showing any of the signs above, don’t wait another rainy season. Call Tilehurst Roofing San Jose at (669) 274-0078 to schedule your free estimate. A live person answers every call, 24 hours a day, 7 days a week. You’ll get a written price before any work starts, a written guarantee on the repair, and a crew of background-checked, uniformed technicians who respect your home and your time. That’s how we do every job, from a small underlayment patch to a full tile re-roof.

Written by Greg Holloway, Owner, Tilehurst Roofing San Jose at Tilehurst Roofing San Jose, serving San Jose and nearby areas.