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Therma-Tru Door Installation: The Lighthouse Point Owner’s Guide
Therma-Tru door installation in Lighthouse Point typically runs $1,800-$4,200 for a complete entry system replacement, depending on whether you’re keeping an existing frame or replacing the full unit with impact-rated hardware. We stock Therma-Tru-compatible jambs, hinges, and threshold assemblies on our trucks, and most Lighthouse Point jobs are surveyed and scheduled within 48 hours. Homeowners usually discover a problem when the door starts sticking in summer humidity, the sweep gaps let water pool after a storm, or the multipoint lock no longer draws the slab tight against the weatherstrip.
Which Therma-Tru Models This Applies To
Therma-Tru’s product lines break into three categories, and the installation approach differs for each. The Classic-Craft and Fiber-Classic series use a compression-molded fiberglass skin over a polyurethane core; these require precise jamb squaring because the slab is heavier than steel and will rack the frame if the rough opening is out of plumb by more than 1/8 inch. The Smooth-Star and Benchmark lines are lighter, but their proprietary hinge mortise spacing (4-1/2 inch heavy-duty ball-bearing hinges, not the standard 4 inch) means aftermarket hinges from the big-box store often leave the door hanging low after six months of salt-air exposure.
To identify your model, check the hinge-side edge of the slab for the embossed date stamp and series code, or the top corner of the frame for the original dealer label. The critical spec for Lighthouse Point is the impact rating: if your home sits east of Federal Highway or within the wind-borne debris region, your replacement must carry a Miami-Dade NOA or Florida Product Approval. We carry both OEM Therma-Tru jambs and UL-rated third-party equivalents that meet the same pressure and missile-impact standards; the decision usually comes down to lead time and whether the original frame is still square.
Signs Your Therma-Tru Door Installation Is Failing

- The slab binds at the top or bottom seasonally. Fiberglass expands and contracts less than wood, but the frame doesn’t. In Lighthouse Point, where afternoon thunderstorms drive humidity from 60% to 90% in hours, a frame installed without proper shimming and sealant will twist. The door catches because the jamb legs are no longer parallel.
- Water pools on the interior threshold after heavy rain. Therma-Tru’s adjustable aluminum thresholds use a replaceable vinyl insert. Once that insert compresses or the end caps crack, water tracks under the sill plate. On canal-front homes near the Lighthouse Point Marina, we’ve found this accelerates when the concrete stoop settles and the threshold no longer sits level.
- Daylight visible around the weatherstrip when the door is closed. The Q-Lon or bulb-style seal compresses permanently over time. A properly installed Therma-Tru uses a kerf-mounted seal that slots into a routed groove; if someone replaced it with a peel-and-stick substitute, the seal migrates and the gap returns.
- The multipoint lock handle lifts but the bolts don’t retract smoothly. Salt corrosion attacks the faceplate and bolt guides first. The mechanism itself often still works, but the installation tolerance was too tight and the bolts are grinding against a corroded keeper.
- The door rattles in the frame during wind gusts. This means the compression weatherstrip has lost its memory, or the hinge screws have backed out of the jamb because the installer used standard drywall screws instead of the 3-inch structural screws Therma-Tru specifies for wind-load transfer.
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AfterReplacement Cost & What’s Included
For Lighthouse Point properties, a Therma-Tru entry door installation breaks down as follows:
- Slab-only replacement (reuse existing frame and hardware): $1,800-$2,600
- Complete prehung unit with standard jambs and threshold: $2,400-$3,400
- Impact-rated prehung with Miami-Dade NOA, multipoint lock, and installation: $3,200-$4,200
What drives the range: frame condition (a rotted sill or out-of-square rough opening requires reframing), impact rating requirements, and whether the installation includes a new lockset or reuses existing hardware. Every quote we write itemizes slab, frame, hardware, labor, and permit fees separately. The price on the measured survey is the price on the invoice. Our 365-Day Done Right Promise covers the installation workmanship, and the Therma-Tru slab carries the manufacturer’s limited lifetime warranty against delamination and finish failure.
DIY or Call Us?

There’s a safe middle ground and a hard stop. A homeowner can check the threshold insert for cracks, verify that hinge screws are tight, and confirm whether weatherstrip is kerf-mounted or adhesive-backed. These checks tell you whether you’re looking at a $45 part or a full installation.
The hard stop is door removal and rehang. A Therma-Tru fiberglass slab weighs 90-140 pounds depending on size and glass lite. The hinges are load-bearing and precisely mortised; shifting them even 1/16 inch changes the lock engagement and weatherstrip compression. More critically, if your home requires impact-rated hardware, improper installation voids the product approval and your insurance coverage. We measure twice, write it down, then we talk price. Call (754) 600-8907 to schedule your free estimate.
FAQs
How long does a Therma-Tru door last in South Florida?
A properly installed Therma-Tru fiberglass door typically lasts 25-30 years in Lighthouse Point, though the threshold insert, weatherstrip, and lock hardware need replacement every 7-12 years due to salt-air corrosion and UV exposure. The fiberglass skin itself does not rot, warp, or rust, which is why we specify it for canal-front and east-facing installations. Call (754) 600-8907 for an exact quote on your replacement - estimates are free.
Can the door be repaired instead of replaced?
Component repairs are practical when the frame is square and only the threshold, weatherstrip, or lock hardware has failed. If the slab is delaminating, the frame is rotted, or the door no longer meets current impact codes, replacement is the only code-compliant path. We offer free second opinions on any written estimate you’ve received. Call (754) 600-8907 and we’ll review it at no charge.
How long does the installation take?
A standard prehung Therma-Tru installation takes one day; impact-rated units with multipoint locks and sidelite configurations typically require two days to allow for proper shimming, sealant cure, and lock adjustment. We arrive with the measured survey you already approved, and the documented photo record is uploaded before we leave. Call (754) 600-8907 to schedule your free estimate.
Do you stock Therma-Tru parts on your trucks?
We carry Therma-Tru-compatible jambs, hinges, threshold assemblies, and weatherstrip on every Lighthouse Point truck, along with impact-rated hardware from our other verified lines: PGT, CGI, and CWS. Full slab replacements are ordered to spec after the measured survey confirms dimensions and series compatibility. Sightline Windows & Doors Lighthouse Point is an independent service provider, not affiliated with Therma-Tru. Call (754) 600-8907 for an exact quote - estimates are free.
Written by Sonia Raman, Owner, Sightline Windows & Doors Lighthouse Point at Sightline Windows & Doors Lighthouse Point, serving Lighthouse Point and nearby areas.










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