Therma-Tru Home Additions & ADU Nationwide

Therma-Tru Home Additions & ADU: The San Diego Owner’s Guide

If you’re planning a home addition or ADU in San Diego and wondering how Therma-Tru doors fit into the picture, the short answer is this: Mason Remodeling Co San Diego installs and integrates Therma-Tru entry doors, patio doors, and sidelight systems into additions and ADUs, with full projects typically running $53,100 to $153,400 depending on square footage, foundation work, and finish level. Most homeowners don’t realize their Therma-Tru product is failing until the door starts binding in the frame, the weatherstripping peels away, or the sill rots out after a few wet winters. Here’s what you need to know before you spend a dollar.

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Key Takeaways

• Home additions in San Diego run $53,100 – $153,400; ADU construction runs $106,200 – $259,600.
• We install Therma-Tru doors as part of additions and ADUs, and we’re an independent contractor, not affiliated with Therma-Tru.
• Isaac Pruett and our crew verify every technician by name and photo before they arrive at your door.
• Written pricing before any work starts, every time. No exceptions.
• 365-Day Done Right Promise: if it’s not right within a year, we fix it at no cost.

Which Therma-Tru Models This Applies To

Therma-Tru builds entry door systems across several series lines, and the model matters more than most San Diego homeowners expect. The Classic-Craft and Fiber-Classic lines are the ones we see most often on additions and ADUs in neighborhoods like North Park, Clairemont, and La Mesa. The Pulse and Benchmark lines are the budget-friendly options that still hold up well but use different hinge prep and threshold dimensions.

Here’s the compatibility gotcha most people miss: Therma-Tru slab widths don’t always match the rough opening you’d assume. A standard 36-inch Therma-Tru door needs a rough opening of 38½ inches by 82½ inches, and if your framing is even half an inch off, the door binds or the weather seal fails within the first year. We measure the rough opening, not the old door, before we order anything. For San Diego’s coastal moisture, we also recommend their rot-resistant sill options, which are standard on most current models but often missing on homes built before 2010.

OEM versus aftermarket: for Therma-Tru specifically, we lean OEM on weatherstripping, sweeps, and sill pans because the tolerances are tight and aftermarket seals rarely seat correctly. For hardware like hinges and locksets, quality aftermarket from Schlage or Baldwin works fine and often saves money. We also stock compatible parts for KraftMaid, Cambria, and Silestone products since additions and ADUs usually touch more than one system.

Signs Your Therma-Tru Home Additions & ADU Is Failing

• Door binds at the top corner or latch side. This usually means the rough opening was undersized or the framing has settled. In San Diego’s clay-heavy soil, slab movement from seasonal moisture shifts door frames more than people realize.
• Visible daylight around the weatherstripping. The sweep or jamb seal has compressed past its useful life. This is the single most common issue we see within five years of installation, especially on west-facing doors that take afternoon sun.
• Water staining on the interior floor near the threshold. The sill pan or threshold cap has failed, or it was never flashed correctly. San Diego may not get much rain, but when it does come, a failed sill shows itself fast.
• Door swings open or closed on its own. The frame is out of plumb. This is a framing issue, not a door issue, and it’s why additions need a contractor who checks the rough opening before the door ever arrives.
• Drafts you can feel with your hand on cold mornings. Even in San Diego’s climate, a poorly sealed Therma-Tru door leaks conditioned air. That’s money leaving your house every month through a gap the width of a dime.

Replacement Cost & What’s Included

For a full home addition or ADU that includes Therma-Tru door installation, San Diego pricing runs $53,100 to $153,400. The range comes down to three things: square footage, whether you’re building on a slab or doing foundation work, and how much of the existing structure we’re tying into. A detached ADU with a new foundation, new electrical service, and two Therma-Tru entry doors will land at the higher end. A bump-out addition with one door replacement lands at the lower end.

What’s included in our pricing: all framing, drywall, insulation, electrical, plumbing rough-in and fixtures, flooring, paint, and the Therma-Tru door system with hardware and weathersealing. We write the price before any work starts, and it doesn’t change unless you change the scope. If the door we install fails within 365 days from the completion date, we come back and fix it at no cost. That’s the Done Right Promise, stated plainly.

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