Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Tamko Home Additions & ADU: The Jacksonville Owner’s Guide
Home additions and ADU construction in Jacksonville typically run $45,000 – $130,000 for a complete project, depending on square footage, foundation work, and finish level. We carry and install Tamko roofing, sheathing, and waterproofing materials as part of every addition we build, and we can match existing Tamko products already on your home. Most homeowners discover they need help when a roofline tie-in leaks, a foundation settles, or an existing roof patch fails at the seam where old meets new.
What you’re usually looking at isn’t a single failed part. It’s a system of parts: Tamko underlayment, flashing, shingles, and the framing that supports them. When one component fails at the transition point between the original structure and the addition, water finds its way in and the damage compounds fast. The fix is rarely a patch. It’s a proper tie-in, done to code, with materials that match what’s already on your roof.
Key takeaways:
- Complete home additions and ADUs in Jacksonville: $45,000 – $130,000 installed.
- Standalone garage conversions: $30,000 – $80,000.
- We match existing Tamko materials so the transition from old roof to new roof is weathertight and visually consistent.
- Written price before any work starts. No numbers that move at the door.
- 365-Day Done Right Promise on every completed project, in writing.
Which Tamko Materials This Applies To
Tamko makes a broad line of residential roofing and waterproofing products, and the compatibility question only matters at the point where new construction meets existing structure. If your home already has Tamko shingles, the most common match points we handle in Jacksonville additions are Heritage and Elite Glass-Seal asphalt shingles, MetalWorks steel shingles, and the underlayment systems Tamko specs beneath them. The roof on an addition has to tie into the existing roofline, which means the shingle profile, exposure, and color need to match or you’ll see the seam from the street.
How to identify what you have: check the roofline for the Tamko stamp on the back of a shingle tab, or look for the product name on the original install documents. If you don’t have paper records, our crews can pull a sample and match it against current Tamko stock. We do this routinely on Riverside and Avondale additions where the original roofs are 15 to 20 years old and the exact color line has shifted.
OEM versus aftermarket: for Tamko-specific underlayment and flashing, we use OEM materials because the manufacturer’s specs drive the warranty. For framing, sheathing, and fasteners, we use code-compliant materials from suppliers we’ve worked with for years. The point is that the Tamko layer specifically needs to be Tamko, because that’s the layer that keeps water out at the transition point. Bradford Remodeling Co Jacksonville is an independent contractor, not affiliated with Tamko, so our recommendation is based on what we see hold up in Florida’s heat and hurricane seasons, not a brand rep’s talking points.
Styles & brands we work with
Signs Your Home Addition or ADU Is Failing
- Water staining at the old roof/new roof seam. This is the number one failure point on Jacksonville additions. The flashing at the tie-in wasn’t stepped correctly, or the original contractor lapped the underlayment the wrong direction. Water follows the path of least resistance, which is exactly where the roof pitch changes.
- Shingle granule loss concentrated on the south-facing slope. Florida sun eats asphalt shingles faster than anything else. If the granules are washing into your gutters every time it rains, the shingle is losing its UV protection and will crack soon.
- Sagging or uneven floor at the connection point between the original slab and the new foundation. Jacksonville’s sandy soil settles. If the addition’s foundation wasn’t properly tied or compacted, the two structures move independently and the seam opens up.
- Doors or windows in the addition that stick in summer. That’s framing movement from humidity cycling, and it usually means the addition wasn’t properly vented or the lumber wasn’t dried before installation.
- Mold or mildew smell in the ADU that never quite goes away. This is almost always an underlayment or flashing failure above, or a ground-moisture problem below. In Jacksonville’s humidity, a small leak becomes a mold problem in weeks, not months.
See the difference
Before
After
Before
After
Before
AfterReplacement Cost & What’s Included
| Scope of Work | Jacksonville Price Range |
|---|---|
| Complete home addition (400 – 800 sq ft) | $45,000 – $130,000 |
| ADU construction (new detached unit) | $90,000 – $220,000 |
| Garage conversion to living space | $30,000 – $80,000 |
| Roof tie-in and reflash where old meets new | $800 – $2,500 (when part of a larger project) |
The range is driven by three things: square footage, foundation type, and finish level. A slab-on-grade addition with builder-grade finishes lands at the bottom. A second-story addition or an ADU requiring a new electrical service and separate utility drops lands at the top. What you won’t see is a price that moves after we start. Bradford Remodeling Co Jacksonville writes the scope and the price before the first tool comes out, and that number holds. Every project includes the 365-Day Done Right Promise: if the work doesn’t hold within a full year, we come back and correct it at no charge. That’s in writing, signed, in your hand at close.
Call (904) 337-5929 and we’ll walk the site, measure the tie-in, and give you a written line-item price for the whole job. No range games. No door-to-door reprice.
DIY or Call Us?
You can safely identify the problem yourself. Walk the roofline, look at the seam where the addition joins the original roof, and check for lifted shingles, cracked flashing, or granule buildup in the gutters. You can check for soft spots on the floor at the foundation transition. You can look for water stains inside at the ceiling corners. That’s useful. That helps us scope it.
What you shouldn’t do is get on a roof in Jacksonville in August, peel back shingles, and attempt a tie-in repair. Roof work at height on a pitch with a laminate membrane underneath is not a weekend project, and a bad tie-in is how the problem started in the first place. Framing, foundation work, and structural changes to an addition or ADU require permits, inspections, and a crew that knows Jacksonville’s wind load requirements. If you’ve got a failing addition, call (904) 337-5929. We’ll scope it right the first time and put the price in writing before anything starts.
FAQs
A properly built addition with a correct roof tie-in should last as long as the original structure: 30 to 50 years for the framing, with the roofing layer needing replacement every 15 to 25 years depending on sun exposure. The weak point is always the transition seam, which is why we flash and lap it to manufacturer spec. Call (904) 337-5929 and we’ll tell you whether your addition has a material problem or a workmanship problem.
Most failing additions and ADUs can be repaired without a full rebuild: reflash the tie-in, replace the damaged sheathing, sister the sagging joists, and re-secure the foundation connection. Full replacement is only necessary when the original work was so substandard that bringing it to code costs more than starting over. We’ll tell you straight which one you’re looking at.
A typical addition takes 3 to 6 months from permit to final inspection. An ADU typically runs 4 to 8 months. The variables are foundation work, utility runs, and the city’s permit review timeline. We don’t pad the schedule and we don’t surprise you mid-project. The scope, the price, and the timeline are all written down before we start.
We keep common Tamko shingle colors, underlayment, and flashing in our Jacksonville inventory, and we order specialty Tamko products as each project requires. If your addition needs a match to an existing Tamko roofline, we’ll sample the existing shingle and order the exact color line. No guesswork, no “close enough” replacements.
Written by Curtis Lane, Owner, Bradford Remodeling Co Jacksonville at Bradford Remodeling Co Jacksonville, serving Jacksonville and nearby areas.
