Therma-Tru Home Additions & ADU Nationwide

Therma-Tru Home Additions & ADU: The Long Beach Owner’s Guide

Therma-Tru entry systems in Long Beach home additions and ADUs typically run $45,000-$130,000 for full addition projects incorporating these doors, with Therma-Tru fiberglass and steel units specifically ranging $2,800-$7,500 installed depending on series and sidelite configuration. We stock Classic-Craft, Smooth-Star, and Pulse series units compatible with Long Beach’s coastal climate, and we carry the common jamb widths and hinge configurations on our trucks. Most Therma-Tru failures we see in Long Beach additions show up as frame separation at the sill or delamination where the afternoon sun hits the west face - the thermal cycling here is harder on fiberglass than inland owners realize.

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Homeowners usually notice the problem when the door sticks seasonally, when daylight shows at the jamb, or when the multipoint lock won’t engage evenly. In a recent Bixby Knolls ADU, the homeowner thought the lock had failed; the frame had actually twisted 3/16 inch from moisture intrusion at the threshold. That’s the pattern: the symptom looks like hardware, but the cause is usually the frame or the seal system.

Which Therma-Tru Models This Applies To

Therma-Tru organizes its residential lines by substrate and skin type, and the right replacement depends on what you’re working with. Classic-Craft uses a mahogany-grain fiberglass skin with a polyurethane core; Smooth-Star is paint-ready fiberglass with a smoother surface; Pulse is the contemporary line with aluminum stiles and rails. Each uses different jamb depths, threshold profiles, and multipoint hardware footprints.

To identify your unit, check the hinge-side jamb for the white adhesive label with the 8-digit model code and manufacture date. The first three digits indicate the series: CCA for Classic-Craft, SMT for Smooth-Star, PLS for Pulse. The fourth digit shows the door size in feet and inches. If the label is gone, measure the slab thickness (1-3/4 inch standard, 2-1/4 inch optional on Classic-Craft) and the jamb depth (4-9/16 inch or 6-9/16 inch for 2×6 walls).

We source OEM frames, sills, and weatherstrip kits direct from Therma-Tru for warranty continuity, but we’ve also vetted Endura and Pemko aftermarket sills that match the profile and carry their own 10-year finish warranty. For ADU projects in Long Beach where the original install was done to a tight budget, the aftermarket sill often outperforms the original. We note the source on every quote - no surprises, no generic “comparable” language.

Signs Your Therma-Tru Home Additions & ADU Is Failing

• The door binds at the top or bottom seasonally. This usually means the frame has racked or the sill has absorbed moisture and swollen. In Long Beach, the marine layer keeps morning humidity high through May and June, and if the sill pan wasn’t flashed correctly during the original addition build, the composite sill core takes on water and expands.
• Daylight visible at the jamb or threshold. The bulb seal or sweep has compressed past recovery, or the adjustable threshold has dropped out of adjustment. Therma-Tru’s adjustable oak sills use a screw-turn mechanism that strips if owners over-tighten; we replace roughly one a month in Shoreline Village and Alamitos Beach additions where owners tried to stop a draft by cranking the screws down.
• Multipoint lock won’t engage at all three points. The locking points are timed to the frame position. If the frame has settled or the hinges have sagged, the center point hits while the top and bottom miss. This is almost always frame, not hardware - replacing the lock set without checking plumb wastes the part.
• Fiberglass skin bubbles or cracks at the bottom rail. Water has breached the skin-to-rail bond. Once the core gets wet, the door is done - fiberglass doesn’t rot, but the structural foam core degrades and the door loses its thermal break. We’ve pulled units in Belmont Shore that looked fine outside but weighed 40 percent more than spec from water logging.
• Finish chalks or fades unevenly. Therma-Tru’s fiberglass carries a 5-year finish warranty, but Long Beach’s UV exposure is severe on west and south faces. Classic-Craft with factory stain holds up better than site-painted Smooth-Star. When we spec a replacement for coastal exposure, we upgrade to the Perma-Finish or recommend a site-applied marine varnish with annual maintenance.

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Replacement Cost & What’s Included

The spread depends on three things: whether we’re fitting into an existing opening or reframing for a larger unit, whether the original flashing integrates with the addition’s weather barrier or needs to be peeled back and redone, and whether the interior trim and casing can be saved. We quote each line separately - slab, frame, hardware, trim, disposal - so you see where the money goes. Under Clause 1 of the Haven Standard, that written price is fixed; if we find rot in the subfloor once the old unit is out, we stop, photograph it, and write a change order before proceeding. No work continues on a surprise.

Our install warranty runs 365 days on labor, and we register the Therma-Tru factory warranty on your behalf - 5 years finish, limited lifetime on the fiberglass structure for original owners. The documented photo record from our visit goes to your email before we leave the site.

DIY or Call Us?

There’s a short list an owner can safely check: verify the threshold adjustment screws aren’t bottomed out, confirm the strike plate hasn’t shifted, and look for obvious frame separation at the corners. If the door is sticking, a carpenter’s square on the jamb will tell you if it’s out of plumb - anything past 1/8 inch over 6 feet means the frame has moved.

What goes wrong fast: pulling a prehung unit without supporting the addition’s structural header, cutting the WRB (weather-resistant barrier) without knowing how to integrate the new flashing, or missing that the sill pan drains to a weep screed that was buried by the original concrete crew. We’ve been called to three Long Beach ADUs this year where the homeowner’s DIY replacement leaked into the subfloor within the first rain. The repair cost tripled the original install quote.

We’re not affiliated with Therma-Tru - we’re an independent contractor who specs and installs their products because the warranty support and part availability work for our clients. If you want a second opinion on a quote you’ve already got, bring it by. We’ll review it line by line at no charge. Call (424) 567-7009 to schedule your free estimate.

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