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Oldcastle Home Additions & ADU: The West Palm Beach Owner’s Guide
Oldcastle home additions and ADU construction in West Palm Beach typically runs $45,000 to $130,000 installed, depending on square footage, foundation type, and finish level. We plan, permit, and build additions and accessory dwelling units that meet Florida wind-load codes and local setback requirements. Most owners call us after discovering water intrusion at the tie-in point between the existing slab and the new foundation, or after a previous contractor left the rough-in exposed and the city flagged the inspection.
If you’re searching for Oldcastle-specific parts or compatibility guidance for a home addition or ADU project, you’ve likely hit a wall with phone tag, vague estimates, or a crew that stopped answering once the permit got complicated. The part that actually fails in these projects isn’t usually a single component; it’s the connection detail where new block or poured concrete meets the existing structure. Get that wrong in South Florida, and you’ll chase leaks and cracks for years.
Which Oldcastle Models This Applies To
Oldcastle manufactures concrete masonry units (CMUs), precast lintels, pavers, and retaining wall systems used extensively in West Palm Beach residential construction. For home additions and ADUs, the relevant Oldcastle products are their standard 8x8x16 CMU blocks, bond beams, and precast sill and lintel units. These are dimensional matches for typical Florida block construction, but the compatibility gotcha is mortar type and tie spacing.
Florida Building Code requires specific vertical and horizontal rebar placement in CMU walls, and Oldcastle block dimensions are consistent with 8-inch nominal wall assemblies. The real decision point for any addition or ADU is whether you match the existing block pattern with OEM Oldcastle units or use an equivalent CMU from a local supplier. For load-bearing tie-ins, we specify the OEM match because compressive strength ratings and moisture absorption characteristics are documented. For non-structural interior partition walls, a quality CMU equivalent does the job without a measurable difference in performance. If you’re not sure which product series you have, check the original plans or look for the Oldcastle stamp on an exposed block in the garage or attic kneewall.
Here’s the compatibility list that matters for West Palm Beach:
- Standard 8x8x16 CMU: matches most 1950s through current West Palm Beach block homes; confirm by measuring an exposed block in the garage.
- Bond beam units: required at the top of all CMU walls for structural tie-down; these are where Florida inspectors look first.
- Precast lintels: used over door and window openings in block walls; sizing depends on opening width and load above.
- Hurricane strapping compatibility: strap embedment depth and fastener type must be approved by the local building official before pour.
Styles & brands we work with
Signs Your Oldcastle Home Additions & ADU Is Failing
Here’s what we see on failed or failing addition and ADU projects across West Palm Beach, from Northwood Village to the subdivisions west of I-95:
- Water staining at the tie-in seam: the flashing or waterproofing between the new and existing wall was never installed correctly, and now every heavy afternoon thunderstorm pushes water into the wall cavity.
- Cracking at the foundation joint: the new slab was poured directly against the old slab without an expansion joint, so thermal movement in Florida’s heat causes the two masses to fight each other and the weaker one loses.
- Doors or windows sticking after the first season: the new framing settled or the block walls were not properly cured before the roof load went on, and now the openings are out of square.
- Rust streaks on block walls below roof tie-downs: the hurricane straps or anchor bolts were not galvanized or stainless, and salt air from the coast is eating them faster than expected.
- Exposed rebar or partially filled cells: the previous crew ran out of grout and left vertical cells hollow, which compromises the wall and will fail a structural inspection.
Each of these has a specific fix, and none of them get better with time. The water and salt problems accelerate, not stabilize.
See the difference
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After
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AfterReplacement Cost & What’s Included
A home addition in West Palm Beach lands between $45,000 and $130,000 installed. An ADU runs higher, from $90,000 to $220,000, because it requires separate utility connections, its own electrical panel, and often a second meter. Garage conversions fall between at $30,000 to $80,000, but we see those less often as true ADUs and more often as conditioned bonus space.
What drives the range is foundation work, tie-in complexity, and finish level. A simple single-room bump-out on a slab foundation with a drywall finish sits at the lower end. A permitted ADU with a kitchen, bathroom, separate electrical service, and impact-rated windows sits at the upper end. Every line item gets written down before we pour anything. Parts and labor are separated on the estimate, and the 365-Day Done Right Promise covers the full installation: if the work fails within a year, we come back and correct it at no charge.
DIY or Call Us?
You can safely check a few things yourself. Look at the tie-in seam between the existing home and any added structure. Check for daylight coming through, missing flashing, or caulk that’s pulled away from the block. Measure an exposed CMU block to confirm 8x8x16 dimensions if you’re matching existing construction. Those observations will help you have a useful conversation with any contractor you call.
What you should not do is attempt structural block work, tie-in waterproofing, or hurricane-strap retrofitting on your own. These are load-bearing, wind-rated assemblies, and the Florida Building Code is not a suggestion. A bad tie-in fails slowly and expensively. If you’re pricing an addition or ADU in West Palm Beach and want a number that’s real and holds, call us at (728) 203-9809.
FAQs
A properly built CMU addition or ADU in West Palm Beach should last the life of the original structure, typically 50 to 80 years or more, with the main failure points being waterproofing, flashing, and tie-down corrosion rather than the block itself. Salt air shortens the life of unprotected steel connectors by decades. We address corrosion protection in the written scope. Call (728) 203-9809 for an honest evaluation of your specific site. Estimates are free.
Yes, most tie-in failures can be repaired by opening the wall to install proper flashing, adding an expansion joint, or grouting hollow cells, but the cost depends on how far the damage spread. In some cases, particularly with water intrusion that’s been running for years, the affected framing has to come out. We’ll tell you which path is cheaper in the long run. Call (728) 203-9809 for a written assessment.
A typical home addition takes 3 to 6 months from permit to final inspection, and an ADU takes 5 to 9 months depending on utility work and inspection backlogs. The wildcard in West Palm Beach is the permitting timeline, not the construction itself. We sequence inspections to keep the job moving. Call (728) 203-9809 and we’ll map out a realistic schedule with dates in writing.
We source Oldcastle CMU through established local suppliers in West Palm Beach and order the exact block type and count specified for your addition or ADU, so materials are on-site when the masons start. We also work with KraftMaid, Cambria, and Silestone for finishes when the project scope calls for them. Call (728) 203-9809 and we’ll confirm material availability before we ever schedule the pour.
If you want a straight number for your Oldcastle home addition or ADU in West Palm Beach, call (728) 203-9809. We’ll walk the site, tell you what it costs, and put it in writing before any work starts. Straight number, full scope, no surprises after the invoice.
Written by Curtis Lane, Owner, Bradford Remodeling Co – West Palm Beach at Bradford Remodeling Co West Palm Beach, serving West Palm Beach and nearby areas.
