Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Therma-Tru Home Additions & ADU: The Los Angeles Owner’s Guide
If you’re planning a Therma-Tru home addition or ADU in Los Angeles, the total installed cost typically runs between $53,100 and $153,400, depending on square footage, foundation work, and finish level. We install Therma-Tru entry and patio door systems as part of room additions, garage conversions, and backyard ADUs across Los Angeles, matching your existing door hardware and styling so the new space doesn’t look stapled on. Most homeowners reach out because an existing Therma-Tru door in a planned addition has warped, the weatherstripping has failed, or the threshold is letting California sun and rain do real damage. You’ll know it’s time to address the door first when you see daylight through the frame, feel drafts near the floor, or notice the door no longer latches square.
Which Therma-Tru Models This Applies To
Therma-Tru builds entry doors, patio doors, and sidelight systems across several series, and the compatibility question matters more than most people expect. The Classic-Craft, Fiber-Classic, Pulse, and Benchmark series each use different slab thicknesses, hinge spacing, and threshold profiles. A Classic-Craft door slab won’t swap into a Pulse frame without modifying the rough opening, and that’s a mistake we see from owners who order a slab online based on a photo. The reliable way to identify your door is the AAMA label on the hinge edge, which lists the series, size, and manufacturing date. If that label is gone, measure the slab thickness: 1-3/4 inches points to Classic-Craft or Fiber-Classic, while 2-1/4 inches is typical of the Pulse series. For additions and ADUs, we recommend staying with Therma-Tru OEM components rather than aftermarket slabs because the frame-to-slab seal depends on matched weatherstripping profiles. Mason Remodeling is an independent contractor and not affiliated with Therma-Tru, but we work with their product lines daily and keep the common parts on hand. We also carry components for KraftMaid, Cambria, and Silestone products when a project ties cabinetry or surfaces into the door opening.
Styles & brands we work with
Signs Your Therma-Tru Home Additions & ADU Is Failing
- Daylight visible around the closed door. This usually means the weatherstripping has compressed or the frame has settled. In Los Angeles, the combination of hard sun and seasonal rain cycles causes fiberglass frames to shift more than they would in stable climates, and a door that leaked light in June will leak water by January.
- Door won’t latch without lifting the handle. Sagging hinges or a worn threshold are the common culprits. The fix is often a hinge shim or threshold replacement, but ignoring it accelerates wear on the strike plate and lock set.
- Drafts near the bottom of the door. The adjustable threshold cap loses its seal over time, especially in homes where the door faces west and takes hours of afternoon heat. Therma-Tru thresholds are replaceable components, not a full door replacement.
- Sidelight glass fogging or visible condensation inside the panes. Once the seal on an insulated glass unit fails, the only real fix is replacing the glass unit. This happens more often on south-facing exposures in Los Angeles where thermal cycling is constant.
- Surface cracks or blistering on the door face. Fiberglass doors handle UV well, but a poor installation or an aftermarket paint job with the wrong coating can cause surface failure. Small surface cracks are repairable; cracks that run through the slab are not.
See the difference
Before
After
Before
After
Before
AfterReplacement Cost & What’s Included
For a Therma-Tru door replacement tied to a home addition or ADU project in Los Angeles, the door portion of the work typically runs $5,310 to $17,700 installed, while the full addition or ADU build falls within the $53,100 to $153,400 range from the prior section. The door cost depends on whether we’re swapping a slab into an existing sound frame or tearing out the entire frame and re-setting it, plus whether you’re adding sidelights, transoms, or upgraded hardware. Every price we give is a written line-item quote before work starts, and it includes the door, hardware, weatherstripping, threshold, labor, debris hauling, and a written guarantee covering the installation for 365 days from completion. We don’t hand you a verbal number and then discover additions mid-project. Los Angeles homeowners should also factor in any stucco or drywall repair around the rough opening, which we itemize separately so there are no surprises on the final invoice.
DIY or Call Us?
Replacing a Therma-Tru door is not a high-tension safety hazard the way a garage spring is, but it is a job where the quality of the install determines whether the door performs for five years or twenty. What you can safely check: the hinge screws for looseness, the threshold cap for wear, and the weatherstripping for compression. What an owner should not attempt: pulling and re-setting a full frame without a level and the right shimming technique, especially on an addition where the rough opening was just framed and hasn’t settled. A door that’s out of square by a quarter inch will bind, leak, and eventually warp the slab. If you’re in Los Angeles and already spending addition-level money on the build, the door installation is not the line item to gamble on. Call (803) 680-2547 and we’ll walk you through what we see, what it costs, and who will be at your door with a photo ID badge and name confirmed before arrival.
FAQs
A properly installed Therma-Tru fiberglass entry door lasts 25 years or more in Los Angeles, but the weatherstripping and threshold cap usually need replacement every 5 to 7 years due to UV exposure and seasonal temperature swings. The door slab itself rarely fails; the seals and hardware wear first. Call (803) 680-2547 if you’re seeing drafts or condensation, and we’ll tell you honestly whether it’s a component swap or a full replacement.
Yes, in most cases the repair is limited to the weatherstripping, threshold, hinge shims, or glass unit, and that work typically ranges from $470 to $2,950 in Los Angeles depending on what’s failed. The door slab itself rarely needs replacing unless there’s structural cracking or the frame has shifted past the point of adjustment. Call (803) 680-2547 and describe what you’re seeing, and we’ll give you a straight answer before we ever schedule a visit.
A slab replacement into an existing sound frame takes one day, while a full frame tear-out, re-set, and finish trim typically takes two days. For additions and ADUs, we coordinate the door install with the framing and finish stages so rough opening work and final trim happen without stalling the rest of the project. Call (803) 680-2547 for a project-specific timeline, and we’ll include it in your written quote.
We keep common Therma-Tru thresholds, weatherstripping sets, hinge kits, and strike plate hardware on the truck for service calls across Los Angeles. For full door systems, we order directly through our supplier network with a project-specific lead time that we’ll confirm in writing before you commit. Call (803) 680-2547 and we’ll tell you what’s on the shelf today.
No, your written quote is the price, and we don’t issue change orders for work we should have caught during estimating. The only exception is when we open a wall and find rot, termite damage, or framing problems that were hidden and impossible to see before demo, and even then we’ll show you the condition, explain the fix, and get your approval in writing before proceeding. Call (803) 680-2547 for a line-item quote on your door project, and know that the number we hand you is the number on the final invoice.
Written by Isaac Pruett, Owner, Mason Remodeling at Mason Remodeling, serving Los Angeles and nearby areas.
