Can you re-deck my top deck with Trex and replace any rotten joist under it?
Yes, as long as the rest of the frame passes. A re-deck in Greenwood replaces the boards and railings on your existing structure, and swapping out a rotten joist or two under the top deck is a normal line item on that job, priced from the published table rather than folded into a lump sum. Trex adds one framing rule of its own: the joists have to be close enough together to carry composite. What changes the answer is how many joists have gone, and whether the beam and ledger under them went with them.
Along with replacing any rotten joist under the top deck?
Yes, and it should be written into the quote before the first board comes off. The joists under a deck rot from the top edge down, where water sat in the gap between the old boards for twenty summers. You cannot see most of it from the yard. The honest sequence on a re-deck is to pull the old surface, probe every joist top with an awl, and then price the repair against the published joist line of $1,200 to $4,000 instead of discovering it on day two and calling it a change. A joist that is soft for a foot or two gets sistered with a new pressure-treated joist bolted alongside. A joist that is gone from end to end gets replaced. One to three bad joists under an upper deck is routine. Six or more means the water problem was structural and the beam is next on the list.
Two level decks have their own pattern. The top deck shades the lower one, so the lower frame tends to stay dry while the upper joists take all the weather. The upper joists also carry the stairs between levels, and a soft joist at a stair hanger is the first one to replace, not the last. The underside inspection is where this gets sorted before anyone quotes a number.
Can you also include doing the top sill boards on the top deck with a Trex material?
Yes. The walking surface, the stair treads and the rail cap on the upper deck can all go to Trex while the pressure-treated frame underneath stays. That is the whole point of a re-deck: you keep the structure that still has years and trade the surface that does not. The published re-deck line runs $6,000 to $12,000 and composite sits at the top of it because the boards cost roughly double what pressure-treated costs. In exchange, the staining, sealing and splinter sanding cycle ends for good, and the surface shrugs off the freeze and thaw that retires wood decks around Greenwood every twelve to fifteen years.
Trex is a framing question as much as a surface question. Composite boards flex more than wood, so the manufacturer limits joist spacing to 16 inches on center for boards run straight across and 12 inches for a diagonal lay, with solid blocking where boards end. Builder grade decks across Center Grove and Wanamaker were often framed on 24 inch centers, which was fine for the 2x6 wood that came with them and is not fine for Trex. Adding joists between the existing ones is part of the structural line, and it is the single most common surprise on a composite re-deck quote. A contractor who says Trex will go straight onto a 24 inch frame is telling you the boards will sag within two summers.
How much does a re-deck with Trex and joist work cost in Greenwood?
Each piece has its own line on the published cost guide, and a quote for this job is the sum of the lines that apply, not a number pulled from the size of the house. The ranges below are the table; the firm number comes after the underside inspection, because the joist count is the one thing nobody can see from the driveway. Every deck is different, so call for a same day number on yours.
| Piece of the job | Published range | What moves it |
|---|---|---|
| Re-deck: new boards and rails on a sound frame | $6,000 to $12,000 | Footage and material grade; Trex roughly doubles the material cost of pressure-treated |
| Joist or structural repair (sister or replace one to a few joists) | $1,200 to $4,000 | How many, how long, and whether the beam under them is sound |
| Ledger repair and reflash | $1,500 to $4,500 | Only if the rot reached the house connection; flashing is never optional |
| Stair rebuild to match the new surface | $800 to $2,500 | Height and width; stringers are usually the failed part |
| Full rebuild in composite | $18,000 to $30,000 | The answer when most joists, the beam or the ledger are gone |
A typical upper deck re-deck in Trex with two sistered joists lands in the middle of the first two lines combined. Permits are included in every line, and Greenwood requires one for structural work including joist replacement; the Indiana Residential Code the city enforces is administered through the Indiana Department of Homeland Security. The replacement joists are pressure-treated lumber, which the EPA regulates as a treated wood product and which should be stamped for ground or above ground contact depending on where it sits.
When does a rotten joist turn a re-deck into a rebuild?
When the rot has reached the beam or the ledger, or when the joist count plus the new surface costs about two thirds of a full composite rebuild. At that point you would be paying premium surface money to sit on footings and a ledger from 1994, and the honest contractor says so. These five checks are how we make that call on site, and you can run them yourself with a flashlight and an awl before anyone visits.
- 1Probe every joist top, not just the one you saw
An awl pushed into the top edge of each joist where the old boards sat finds soft wood that still looks fine from below. One rotten joist usually has a neighbor on the way.
- 2Look at the beam and the posts under the bad joists
Joists rot from the top down where water sat between boards. If the beam under them is also soft, the problem is drainage at that end of the deck and the beam comes into the job.
- 3Check the ledger before anything is ordered
The board bolted to the house is the piece that drops decks. Dry, bolted and flashed means a re-deck; rotted or nailed only means the structure goes too.
- 4Measure the joist spacing against the board you want
Trex and most composites want joists no more than 16 inches apart for boards run straight across, and 12 inches for a diagonal pattern. Frames built on 24 inch centers need added joists before composite goes on.
- 5Count the result against the full rebuild line
If joist work plus the re-deck lands past about two thirds of a composite rebuild, the rebuild is the honest answer because it resets footings and ledger too.
If the frame fails, the re-deck and rebuild page walks through what a composite rebuild resets and why it prices the way it does. If it passes, you are back to the first answer on this page: yes, Trex on top and new joists where they are needed, all on one written quote.
What should I ask before I say yes?
Ask who probes the joists and when, ask for the joist spacing in writing next to the Trex product name, ask whether added joists and blocking are in the number or waiting to become a change, and ask who pulls the Greenwood permit. Those four sit inside the ten questions for any deck contractor, and a contractor who answers them without flinching is the one to hire. We answer them on the first call, with the cost table open.
Get the joist count and the Trex number together
Send photos of the top deck and the underside. You get a written range off the public table, and the firm number after the probe.