Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
CertainTeed Home Additions & ADU: The San Francisco Owner’s Guide
We install CertainTeed-specified exterior and interior products as part of home additions and ADUs throughout San Francisco, with full project pricing running $53,100 to $153,400 for a permitted addition and $106,200 to $259,600 for a detached ADU. If a CertainTeed product on your existing addition is failing – siding pulling loose, roof decking showing water damage from a failed underlayment, or window flashing leaking into a new bump-out – we can match the replacement to your model and install it. Most San Francisco owners discover the problem after the first heavy winter rain, when water finds its way past a failed flashing line or a cracked exterior panel.
We are an independent contractor, not a CertainTeed dealer. That means we spec the right CertainTeed product for the job and install it to the manufacturer’s written requirements. Nobody here works on commission from a supplier.
Which CertainTeed Models This Applies To
CertainTeed divides its exterior products into distinct series lines, and the compatibility rules matter. If you have CertainTeed vinyl or polymer siding, the panel profile is usually the key identifier: MainStreet siding uses a standard 4-inch exposure, while CedarBoards uses a wider 6- to 7-inch profile. Mixing profiles on an addition reads wrong from the street and leaves visible seams that catch water. For roofing, CertainTeed’s Landmark shingles use a specific nail line and exposure that does not always transfer cleanly from an older XT series to the current product.
On the OEM-versus-aftermarket question: for structural components like CertainTeed’s drywall, insulation batts, and backer board, a quality aftermarket equivalent is often indistinguishable in function and costs 20 to 30 percent less. But for anything weather-facing – siding, shingles, flashing, housewrap – we recommend sticking with the manufacturer’s own product. The warranty on a failed flashing seam is worthless if the replacement material is not the one named on that warranty. When we show up in San Francisco, we photograph the manufacturer label, confirm the series and color code, and order against that specific SKU. No guesswork.
A compatibility gotcha we run into often: CertainTeed’s DiamondBack housewrap and its roofing underlayments are not interchangeable. DiamondBack is a high-permeability wall wrap. Roofing underlayment is an asphalt-saturated product meant to sit under shingles. A previous contractor using wall wrap on a roof deck in the Outer Sunset is exactly the kind of thing we find during a teardown – and it’s why the plywood underneath is spongy. Two different jobs, two different products.
Styles & brands we work with
Signs Your CertainTeed Home Additions & ADU Is Failing
- Water staining on interior drywall near the roofline or exterior wall. This usually means flashing failed where the addition ties into the original structure. San Francisco’s wind-driven rain pushes water sideways into any gap.
- Vinyl or polymer siding panels that have popped loose at the bottom edge. The locking channel is broken or the panel was over-driven during the original install. Once one panel loses its lock, wind gets behind the whole run.
- Shingle granules accumulating in gutters or at the downspout exits. Granule loss indicates the asphalt layer on the shingle is breaking down. A CertainTeed Landmark roof in San Francisco’s fog and salt air typically loses granule adhesion faster than in a dry climate.
- Visible gaps at window and door trim on the addition. The exterior trim was likely caulked but not properly flashed. Caulk alone fails within two to three years in San Francisco’s wet-dry cycles.
- Musty odor in the ADU that does not clear with ventilation. This points to moisture trapped behind a vapor barrier that was installed on the wrong side of the wall assembly. In San Francisco’s marine climate, a mis-placed vapor barrier traps moisture inside the framing cavity.
See the difference
Before
After
Before
After
Before
AfterReplacement Cost & What’s Included
Replacing specific failing components on a San Francisco addition runs on a parts-and-labor basis, with most repair scopes landing between $945 and $23,600 depending on what failed. A full home addition falls at $53,100 to $153,400. An ADU is a different line item entirely at $106,200 to $259,600. The spread is driven by what we find when we open the wall or roof: a failing window can cost $5,310 to $17,700 to replace, while a roof tear-off and re-sheathing hits $9,440 to $23,600.
Every quote we give in San Francisco includes a written line-item breakdown before work starts. Parts are priced at our cost plus a published margin. Labor is priced by the day, not by the square foot. The written price does not move at the door – that’s The Garrison Standard, and we’ve held to it since 2004. Every completed job carries the 365-Day Done Right Promise: if the work fails within a year, we return and correct it at no charge. You get the signed guarantee in your hand before we leave the site.
DIY or Call Us?
You can safely do the inspection work yourself. Check for popped siding panels, walk the perimeter, look for staining, and photograph any damage. What you should not do is cut into an exterior wall or roof assembly on a San Francisco addition. The moment you open a wall, you are exposing the framing to the same fog-driven moisture that caused the original problem. For anything involving roof access on a two-story San Francisco addition, stay off the ladder. Steep roof pitches and wet shingles are a combination that hurts people. Curtis Lane has seen enough torn-off flashing on Outer Sunset teardowns to know exactly where water finds its way in – and it’s never where the homeowner expected. Call (831) 610-5598 and we will put a trained set of eyes on it. The inspection costs you nothing.
FAQs
CertainTeed Landmark shingles typically carry a limited lifetime warranty, but in San Francisco’s fog, salt air, and wind-driven rain, the functional life runs 20 to 25 years before granule loss and seal failure start showing. Vinyl and polymer siding panels hold up 30 to 40 years with proper flashing, but the caulk joints at trim need maintenance every 3 to 5 years. Call (831) 610-5598 and we can walk you through what the current condition means for your timeline.
That depends on the part. A single popped siding panel can sometimes be re-locked. A failed flashing seam can be repaired without tearing out the wall. But a shingle roof with widespread granule loss should be replaced, not patched – patching a roof in San Francisco just moves the leak to the next failed shingle. We will tell you which category your problem falls into.
A window replacement on a San Francisco addition runs one to two days. A siding repair runs one to three days. A roof replacement runs five to ten days depending on pitch and access. A full addition or ADU is a multi-month project. We give you a written schedule with every quote, and we hold to it.
We stock common CertainTeed flashing profiles, sealants, and trim stock on every truck. Siding panels, shingles, and underlayment are ordered by SKU once we confirm the series and color code on your existing product. San Francisco jobs usually have materials on site within four to seven business days.
Written by Curtis Lane, Owner, Bradford Remodeling Co – San Francisco, CA at Bradford Remodeling Co San Francisco, serving San Francisco and nearby areas.
