Therma-Tru Home Additions & ADU Nationwide

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

We stock and install Therma-Tru entry systems and fiberglass door units for home additions and ADU projects in West Palm Beach, with typical installed pricing from $45,000 to $130,000 for full additions and $90,000 to $220,000 for detached ADUs. Therma-Tru fiberglass doors come with the door slab, frame, hinges, and weatherseal as a matched system, and we carry compatible components for Classic-Craft, Smooth-Star, and Fiber-Classic series on our trucks. Most West Palm Beach homeowners discover a problem when the door won’t latch after seasonal humidity shifts, or when they feel a draft around the perimeter of a door that worked fine last winter.

Call (561) 475-3903

Which Therma-Tru Models This Applies To

Therma-Tru organizes its residential entry doors into three core series, and each uses slightly different frame profiles and hinge locations. Classic-Craft uses a thicker, more detailed fiberglass skin with a wood-edge construction that requires a specific hinge mortise depth, 3/8 inch rather than the standard 1/4 inch. Smooth-Star has a cleaner, paint-ready surface and uses a composite frame system with integrated composite hinges that are not interchangeable with standard steel hinges. Fiber-Classic, the original series, uses a wood-grain fiberglass skin with a traditional wood frame that accepts standard hinges but requires a specific corner seal gasket, part number 4100-series, that differs from the bulb seal used on Smooth-Star.

To identify your unit, check the hinge edge of the door slab for a stamped date code and series mark, or remove a hinge and look for a foil label on the frame rabbet. The OEM frame and hinge set runs about 40 percent more than quality aftermarket equivalents, but on Classic-Craft we spec OEM hinges because the mortise depth mismatch causes binding within two humid seasons in West Palm Beach. For Smooth-Star, the composite hinge is proprietary, so aftermarket is not an option. We stock OEM Classic-Craft hinge sets, Smooth-Star composite hinges, and both the 4100-series and bulb-style weatherseals on our trucks.

Signs Your Therma-Tru Home Additions & ADU Is Failing

• Door sticks or binds in the frame. West Palm Beach’s humidity cycle, 85 percent in August down to 60 percent in January, causes fiberglass slabs to expand and contract differently than the composite frame. The gap between slab and jamb should stay at 1/8 inch; when it closes to nothing, the door drags or won’t close without force.
• Visible daylight around the door perimeter. The bulb-style or fin-style weatherseal compresses permanently after three to five years of UV exposure and salt air. Once the seal loses memory, conditioned air escapes and the gap becomes visible when you stand inside on a bright day.
• Hinge screws loosen repeatedly. The composite frame in Smooth-Star and the wood-edge frame in Classic-Craft both use specific screw thread patterns. Standard wood screws strip the composite; standard machine screws don’t bite the wood edge. Stripped hinge mortises let the door sag until it rubs the threshold.
• Threshold cap lifts or separates. Therma-Tru thresholds use an adjustable cap with a vinyl seal underneath. Sand and grit tracked in from West Palm Beach driveways grind the seal flat, and the cap itself cracks from repeated foot traffic and thermal cycling.
• Corner seal gaskets crumble at the frame bottom. These small foam blocks sit where the jamb meets the sill, and they harden first because they sit in the water path. A failed corner seal lets water run behind the trim and into the subfloor, which we find regularly in additions built before 2015.

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Replacement Cost & What’s Included

What drives the range: slab size and glass configuration, whether the frame is standard or impact-rated for Florida Building Code compliance, and how much reframing the opening needs. We quote a flat written price before any work starts, with parts and labor itemized. Under Clause 1 of the Haven Standard, that written price includes a 365-Day Done Right Promise on the installation. No change proceeds without a signed change order, which is how we’ve kept projects within a few percent of the agreed number across 4,000-plus jobs since 2007.

DIY or Call Us?

An owner can safely check the gap around the door with a dollar bill, it should drag slightly but pull through, and can confirm whether the threshold cap lifts by pressing down with a thumb. You can also verify hinge screw tightness with a screwdriver, though stop if the screw spins without biting. Where DIY goes wrong is in the adjustment: shimming a sagging Therma-Tru door requires knowing whether the frame is composite or wood-edge, because the shim material and screw type differ. Over-tighten a composite frame and the hinge pocket cracks; use the wrong screw in a wood edge and the hinge pulls out within a season. We also see homeowners damage the corner seal gasket trying to pry it out with a putty knife. For a door that won’t latch or seal, call (561) 475-3903 and we’ll diagnose it on the first visit, with a written price before any work starts.

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