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Therma-Tru Home Additions & ADU: The Woodland Hills Owner’s Guide
If you’re planning a home addition or ADU in Woodland Hills and want Therma-Tru doors in the mix, here’s the short answer: an addition that uses Therma-Tru entry systems typically runs $45,000 to $130,000 installed, depending on square footage, foundation work, and how many exterior doors the design calls for. We’re an independent general contractor, not affiliated with Therma-Tru, but we install their door systems regularly across the West Valley. Most Woodland Hills owners don’t discover a door problem until the addition is already framed and the old door won’t seal, or the new slab has shifted enough that a factory-hung unit won’t close square.
That’s the moment this page matters. A Therma-Tru door is only as good as the rough opening behind it, and in Woodland Hills that means dealing with expansive clay soil, summer heat that warps unsealed jambs, and hillside lots where drainage runs right at the threshold. We see it constantly on Warner Center ADUs and the older ranch homes off Ventura Boulevard.
Which Therma-Tru Models This Applies To
Therma-Tru builds entry doors under several series names: Classic-Craft (their fiberglass wood-grain line), Smooth-Star (painted smooth fiberglass), Pulse (their newer polyurethane-core line), and the Benchmark line sold through retail channels. The critical compatibility issue we run into on additions in Woodland Hills is jamb depth. Standard interior-wall rough openings are framed with 2×4 walls, but exterior walls on California additions almost always use 2×6 framing for insulation code, which means the door system needs a 6-9/16″ jamb, not the 4-9/16″ version many homeowners accidentally order. Measure the wall depth before you buy anything. That single spec mismatch is the most common reason a brand-new Therma-Tru unit gets returned or sits in the garage for three months.
The second gotcha is slab versus sill. Therma-Tru fiberglass slabs (the door panel itself) can be ordered pre-hung or as a slab-only replacement. On a home addition, if the existing frame is square and solid, a slab swap can work. If the rough opening has moved, you’re fighting the frame forever. We’ll tell you which one applies, and we don’t upsell you into a full pre-hung unit if the slab is all you need.
Styles & brands we work with
Signs Your Therma-Tru Home Additions & ADU Is Failing
- Gaps at the top or latch side that change with the season. Expansive soil in Woodland Hills moves foundations by small fractions, and the door’s reveal (the even gap around the slab) is the tell. A consistent gap is usually hinge wear; a shifting gap is structure.
- The door scrapes the threshold or won’t latch without lifting the handle. This usually means the jamb has settled out of square, or the threshold adjustment screws were never set after the slab pour cured.
- Condensation or fog between the glass panels in a Therma-Tru door with an integrated window lite. The insulated glass seal has failed. On a Canyon-area ADU exposed to full afternoon sun, we see this within 6 to 10 years even on well-installed units.
- Visible rust on the hinge screws or the bottom sweep (the strip that seals the gap under the door). If drainage isn’t directed away from the addition’s entry, water pools at the threshold and eats hardware fast.
- The door swings open or shut on its own once it’s past 30 degrees open. That’s an out-of-plumb frame, and on a new addition it means the rough opening wasn’t squared before the door went in.
See the difference
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After
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After
Before
AfterReplacement Cost & What’s Included
For a home addition or ADU in Woodland Hills, the overall project runs $45,000 to $130,000, and a Therma-Tru door system is one line item inside that. A new pre-hung Therma-Tru Classic-Craft or Smooth-Star entry, installed, typically adds $1,800 to $4,500 to the project depending on size, glass options, and whether the rough opening needs reframing. A slab-only swap on an existing frame lands lower, usually $800 to $1,800. The wider number above covers the full addition scope: foundation, framing, roofing, drywall, electrical on its own circuit, and finish work.
Every estimate we write is a fixed line-item price before work starts, and the 365-Day Done Right Promise covers the install for a full year. If the door doesn’t close square in month eleven, we come back and make it right. That’s in writing, not a handshake.
DIY or Call Us?
You can check a few things yourself before calling anyone: look at the reveal gap around the slab (it should be even, about an eighth of an inch top to bottom), check whether the threshold screws are flush, and confirm the wall depth with a tape measure (4-9/16″ vs 6-9/16″). Where DIY goes wrong on an addition is the rough opening. If the framing is out of square, no amount of hinge adjustment fixes it, and forcing a fiberglass slab into an out-of-square frame can crack the skin or break the corner seal, and that’s a $400 mistake on a $1,800 door. We’d rather you spend five minutes with us on the phone at (341) 217-2776 and find out whether it’s a fastener issue or a framing issue before you start pulling hinges.
FAQs
20 to 30 years for the fiberglass slab itself, but hardware, weatherstripping, and the adjustable threshold typically need replacement at the 8 to 12 year mark in Woodland Hills heat and sun exposure. The door rarely fails; the seals and hardware fail first. Call (341) 217-2776 and we can tell you which part is the problem just from a photo.
Usually yes, if the frame is still square. Fiberglass slabs don’t warp like wood, so sagging is almost always hinge or jamb related, and both are repairable. We’ll quote the repair honestly, and if replacement is the smarter move, we’ll show you the math on both. Estimates are free.
One day for a pre-hung unit swap with no framing work. If the rough opening needs reframing or re-squaring, plan for two days and a little drywall touch-up. We’ll confirm the schedule and a live arrival time before we show up, and you get photo updates before and after the work.
We carry common slab sizes, adjustable thresholds, bottom sweeps, hinge screws, and weatherstripping on the truck, and we source Therma-Tru-specific components from local Woodland Hills suppliers when a special size or glass lite is called for. That saves you a second trip and a second appointment. Call (341) 217-2776 and we’ll confirm stock before we come out.
The work tells you everything. We just make sure it tells the right story. If you’re staring at a door on your addition or ADU that won’t seal, square, or latch, call us at (341) 217-2776 for a free estimate. We’ll put the price in writing before anything gets pulled off its hinges.
Written by Luca Romano, Owner, Sawyer Remodel Woodland Hills at Sawyer Remodel Woodland Hills, serving Woodland Hills and nearby areas.
