







Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Tamko Home Additions & ADU: The West Palm Beach Owner’s Guide
When a homeowner in West Palm Beach calls us about a Tamko home addition or ADU, the conversation usually starts the same way: they have a plan, a budget in mind, and a lot of questions about what the finished space will actually cost. We install and build Tamko-compatible home additions and accessory dwelling units with a written price before any work starts, typically ranging from $45,000 to $130,000 for a home addition and $90,000 to $220,000 for a full ADU in this market. The most common sign that a Tamko-related addition or ADU component has failed is water intrusion at a seam, a roof transition, or a window rough opening, often showing up as a soft spot near the sill or a stain that spreads after a heavy rain. Some homeowners also discover the problem through a failed inspection flag on an existing structure, or a foundation issue that shows up once the drywall comes down.
We work with Tamko-branded roofing and building envelope products as part of larger addition and ADU builds throughout West Palm Beach, and we treat every existing structure as something to be understood before it is added onto. Graham Stein walks each job site himself before the first drop cloth goes down, and the written scope of work is in your hands before the first tool is unpacked.
Which Tamko Models This Applies To

Tamko manufactures a range of building products that show up in home additions and ADU construction, including asphalt shingles, self-adhered underlayments, and decking materials. The compatibility question that matters most for a West Palm Beach addition is not which Tamko product you have, but which layer of the building envelope it belongs to and whether it was installed to match our local wind and moisture codes. Tamko’s self-adhered underlayment lines, for example, come in different thicknesses and adhesive formulations, and not all of them are rated for the high-heat attic conditions we see in South Florida.
For an OEM versus aftermarket decision on Tamko products, we generally recommend staying with Tamko or a manufacturer-equivalent for any self-adhered or waterproofing layer. The reason is simple: mixing a Tamko underlayment with an off-brand flashing tape creates a seam where two adhesives meet, and that seam is where Florida humidity does its slow work. When we open a wall on an older West Palm Beach addition and find a failed seam, the fix is rarely the board itself. It is usually the transition, and the transition failed because the two products were never designed to bond to each other. We also stock parts for KraftMaid, Cambria, and Silestone finishes that commonly go into the interior of these additions, so the same crew that builds the envelope can finish the inside without a second subcontractor walking the job.
Styles & brands we work with







Signs Your Tamko Home Additions & ADU Is Failing
- Water staining at the roof-to-wall transition on a new or existing addition. This is the number one call we get in West Palm Beach, and it usually means the step flashing or the underlayment at that junction was lapped the wrong direction. Water runs downhill, and a backward lap gives it a runway into the wall cavity.
- A soft or spongy floor near any exterior door on the addition. In Florida, the sill and the threshold take more standing water than anywhere else on the building envelope. When the sill pan was not flashed properly under a Tamko underlayment, the subfloor wicks moisture and starts to fail from the bottom up.
- Visible cracking or separation at the seam where the new addition meets the original house. Additions move slightly differently than the original structure, especially during the seasonal shift from dry to humid. A correctly detailed seam allows for this movement; a poorly detailed one opens up and lets air and water through.
- Mold or musty smell inside the ADU within the first year. That smell is almost always trapped moisture behind the wallboard, and it points to a vapor barrier or underlayment that was not detailed correctly at the corners and penetrations. By the time you smell it, the damage has been happening for months.
- Fastener pops or nail heads pushing through the drywall on an exterior wall. When the building wrap or underlayment allows moisture behind the sheathing, the lumber swells and the fasteners back out. It looks like a cosmetic drywall issue, but it is a building envelope failure.
See the difference
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After
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AfterReplacement Cost & What’s Included

For a full home addition in West Palm Beach, the installed range runs from $45,000 to $130,000 depending on square footage, foundation type, and the level of interior finish. A detached ADU runs from $90,000 to $220,000 because it is a complete standalone structure with its own foundation, electrical service, plumbing, and HVAC. The range is wide because two additions that look similar on paper can be very different once we open the ground: one may sit on stable sandy loam that needs nothing beyond a standard footing, while the one next door may require deeper piers, additional tie-downs for wind code, and a more involved drainage plan.
Every price we give is written before any work starts, itemized by labor and materials, and it does not change because the crew found a surprise behind the wall. That is the Cedarwell Care Promise, and it is stamped on every project. The crew wears shoe covers inside the house, drop cloths go down on every floor path, and a photo of the clean-up is taken before the crew leaves. If something is not done right after the job is complete, our 365-Day Done Right Promise means we make it right.
Tamko Home Additions & ADU work in West Palm Beach typically runs $45,000 – $130,000, with a detached ADU at $90,000 – $220,000. Call (728) 203-3270 for a written, itemized quote before you commit to anything.
DIY or Call Us?
An addition or ADU is not a DIY project, and we will say that plainly. The structural, electrical, and waterproofing work requires a licensed contractor who pulls the permits and passes the inspections. What a homeowner can reasonably do is document what they see: take photos of any staining, measure the affected area, and note when the problem first appeared. That record helps us diagnose the scope before we open a single wall.
What we would not recommend is opening the wall yourself to find the source. Once the drywall is off and the framing is exposed to Florida humidity, the clock starts running on moisture intrusion, and the repair gets more involved than it needed to be. If you have a Tamko product that is failing or a Tamko addition that needs to be built right, call (728) 203-3270. We will look at the site, put the price in writing, and then do exactly that.
FAQs

A properly built addition in West Palm Beach should last 30 to 50 years for the structural shell, with the roof and building envelope components needing inspection every decade due to salt air and hurricane-season moisture. Tamko products installed correctly with proper flashing and underlayment hold up well here, but the detailing at seams and transitions matters far more than the brand on the box. Call (728) 203-3270 if you want an honest assessment of what you have.
Yes, in most cases a failing seam, flashing detail, or underlayment section can be repaired without rebuilding the entire addition, provided the framing behind it is still sound. The cost depends on how far the moisture traveled before it was caught. Call (728) 203-3270 and we will tell you what we find, not what we hope you will pay.
A standard home addition takes 3 to 6 months from permit to final inspection in West Palm Beach, and a detached ADU takes 5 to 9 months depending on site conditions and utility connections. We give you a firm start and end window in writing before the first tool is unpacked. Call (728) 203-3270 for a timeline specific to your property.
We order Tamko materials for each project based on the written scope of work, and we verify compatibility of every layer before installation begins. We also keep common transition materials and flashing components on hand for repairs. Call (728) 203-3270 and we will confirm what your project needs.
Written by Graham Stein, Owner, Elmstead Remodeling West Palm Beach at Elmstead Remodeling West Palm Beach, serving West Palm Beach and nearby areas.


