CertainTeed Home Additions & ADU Nationwide

CertainTeed Home Additions & ADU: The Pomona Owner’s Guide

We stock and install CertainTeed-compatible siding, roofing, and trim systems for home additions and ADU construction in Pomona, with typical installed project costs running $45,000-$130,000 for home additions and $90,000-$220,000 for detached ADUs. Most CertainTeed material orders arrive within 3-5 business days, and we schedule framing start once your selection is locked and permits are in hand. Homeowners usually discover a material compatibility issue when their addition’s siding doesn’t match the existing CertainTeed profile, or when water intrusion at the addition junction reveals the original builder used a discontinued CertainTeed shingle line that can’t be sourced for the new roof plane.

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Which CertainTeed Models This Applies To

CertainTeed’s product lines for additions and ADUs break into three categories: siding (Cedar Impressions, Monogram, MainStreet, and Board & Batten), roofing (Landmark, NorthGate, Presidential Shake, and Highland Slate), and trim/millwork (Restoration Millwork PVC boards and CertaTrim). The critical compatibility gotcha in Pomona is the shingle exposure height: Landmark PRO carries a 5 5/8″ exposure, while original Landmark is 5″, and mixing them on the same roof plane creates a visible step that fails inspection.

To identify your existing CertainTeed product, check the nail line printing on shingle bundles remaining in your garage, or look for a small embossed stamp on vinyl siding panels near the bottom lock. For roofing, the color name and lot number matter: CertainTeed’s Max Def color granules shift slightly between production runs, and a 2025 lot of Burnt Sitter won’t blend with a 2018 installation. We source from CertainTeed’s Rancho Cucamonga distribution point when possible to minimize lot variance on Pomona jobs.

OEM CertainTeed vs. quality aftermarket: for siding, we specify CertainTeed originals because the panel lock geometry is proprietary. For roofing underlayment and ice-and-water shield, we often use CertainTeed’s DiamondDeck or a comparably spec’d Grace product, depending on what’s moving through distribution that week. Measure twice, then we can talk.

Signs Your CertainTeed Home Addition or ADU System Is Failing

• Siding panels buckling or oil-canning in Pomona’s afternoon heat. This happens when the original installer nailed Monogram or Board & Batten too tight, not allowing for thermal expansion across the 30-40 degree daily temperature swing common near the Pomona Fairplex corridor. The panel can’t move, so it tents between fasteners.
• Water staining at the addition-to-house junction after Santa Ana wind events. The step flashing or sidewall flashing was likely terminated wrong, or the CertainTeed siding was butted tight against the roof instead of carrying a 1″ minimum clearance above shingles. Wind-driven rain finds that gap every time.
• Granule loss on the addition roof showing black asphalt substrate. CertainTeed’s mid-tier Landmark shingles carry a 10-year SureStart warranty, but Pomona’s UV exposure and occasional hail from winter storms accelerate oxidation. If you’re seeing bald patches at year 8, the shingle is failing early and the warranty claim window is narrowing.
• Interior drywall cracks running diagonally from addition corners. This usually traces to inadequate foundation separation: your ADU or addition is settling on its own footing while the main house sits on original compacted fill, and the CertainTeed wall system is rigid enough to telegraph that movement through tape joints.
• Soft or punky Restoration Millwork trim where sprinklers hit daily. PVC trim doesn’t rot, but it will wick water at cut ends if the factory coating is field-cut and not resealed with PVC cement. We see this behind foundation planting beds in Pomona’s older Lincoln Park neighborhood regularly.

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Replacement Cost & What’s Included

The spread within each range comes down to three things: what’s behind the wall or under the roof that we can’t see until tear-off, the CertainTeed product tier you select (Landmark vs. NorthGate synthetic slate is roughly double the material cost), and whether your Pomona property requires retaining walls or grading to meet setback. Under Clause 1 of the Haven Standard, you get a written price before anyone picks up a tool, and no change proceeds without a signed change order. The 365-Day Done Right Promise covers workmanship; CertainTeed’s own product warranty covers material defects.

DIY or Call Us?

There’s a clear line here. An owner can safely walk the addition, photograph the CertainTeed product stamps, and check the city of Pomona’s ADU setback calculator online to see if their plan qualifies under state law. What goes wrong past that point is structural: cutting into the existing roof plane to tie in an addition requires temporary shoring knowledge most homeowners don’t carry, and the California Building Code’s Title 24 energy requirements for ADU insulation and HVAC sizing are easy to miss by a few R-values or CFM and fail inspection.

We’re not affiliated with CertainTeed; we’re independent contractors who specify their products when the job calls for them. If you’re holding a competitor’s quote and want a line-item review, our Free Second Opinion applies here too. Call (626) 606-1081 to schedule your free estimate.

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