Every siding company will tell you to replace everything. It is the bigger job, so of course they will. But plenty of houses do not need it, and a well done repair can buy you eight or ten more years for a fraction of the cost. The trick is knowing which situation you are in, and the answer usually comes down to three things: how much of the wall is bad, why it went bad, and what is behind it.
The 20 percent rule, and why it is only a starting point
The usual rule of thumb is that if less than 20 percent of your siding is damaged, repair it, and above that, replace it. That is a reasonable first filter, but it misses the more important question, which is whether the damage is scattered or concentrated.
Twenty percent spread evenly across all four walls usually means the material itself is failing. Every board is the same age and has taken the same weather, so the ones that look fine today are simply a year or two behind the ones that do not. Patching in that situation is a treadmill.
Twenty percent concentrated on one wall, or under one window, or along one downspout run, is a completely different story. That is not material failure. That is a specific water problem in a specific place, and fixing the cause plus replacing that section is the correct and much cheaper answer.
Find out why before you decide what
This is the step people skip. Before you price anything, figure out what actually put water into that wall. The usual suspects are short and predictable:
- A gutter that overflows or a downspout that dumps against the wall.
- Flashing missing or installed backward above a window or door.
- No kick out flashing where a roof edge meets a wall, so every rain runs behind the siding.
- A deck ledger or a hose bib penetrating the wall without a proper seal.
- Grade or a flower bed built up so the bottom of the siding touches soil.
- Sprinklers hitting the wall every morning.
If you replace the siding on that wall and do not fix the cause, you have bought yourself a very expensive delay. If you fix the cause, a targeted repair often holds for as long as the rest of the house.
When repair is clearly the right call
Repair, with confidence, when all of these are true:
- The damage is limited to one area or one wall.
- The rest of the siding is sound when you press on it and straight when you sight down it.
- You can identify and fix the water source.
- Your siding is a product still being made, or you have leftover material, so the patch can match.
- The sheathing behind the damaged section is mostly intact.
Typical cost for a repair like that runs 800 to 4,000 dollars depending on how much wall comes off and how much framing needs attention. Compare that to 20,000 or more for the whole house and the decision makes itself.
When replacement is the honest answer
Replace when you see any of these:
The damage is everywhere. Cupping, cracking, or soft spots on three or four walls means the material is at the end of its life. You will be back on a ladder every spring.
You cannot match it. Discontinued profiles and colors are common, especially with vinyl from the 1990s and with older hardboard. A patch that does not match turns a maintenance issue into a permanent eyesore, and it hurts resale.
The sheathing or framing is compromised over a large area. Once you are rebuilding structure across multiple walls, the siding is the cheap part of the job. Take it all off, do the wall correctly, and put new material on.
There is no weather barrier, or it has failed. Plenty of homes built before the 1980s have nothing behind the siding but boards. You cannot install a proper barrier without removing the siding, and the barrier is the thing actually keeping your house dry.
You have already repaired this wall twice. Three strikes. At some point the repairs cost more than the replacement would have.
You want a different look. Perfectly valid. If you are changing the exterior anyway, do it once.
Running the numbers honestly
Here is a way to compare that keeps you honest. Take the repair quote and ask how many years it realistically buys. Then take the replacement quote and divide by the expected service life of the new material.
Say the repair is 3,000 dollars and buys 8 years. That is 375 dollars a year. Say replacement is 24,000 dollars in James Hardie fiber cement with a 40 year life. That is 600 dollars a year, and it comes with a new weather barrier, new flashing, and a warranty. The repair still wins on cash flow, but the gap is smaller than it looks on the invoice.
Now change the repair to one that buys 3 years. That is 1,000 dollars a year, and suddenly replacement is the better deal on pure math, before you count the value of not worrying about it.
The middle path people forget
You do not have to do the whole house in one season. On many homes we replace the one wall that faces the weather, fix the cause, and leave the other three for three or four years. The trick is planning it so the materials and the trim details line up when you come back, rather than ending up with a house that looks like it was assembled from two projects.
If you are going to phase it, say so at the first estimate. A good contractor will pick a product line with staying power, record the exact color and profile, and write the phasing into the plan.
Get a real look before you choose
You cannot answer this question from the curb, and neither can a contractor. It takes pulling a board or two in the worst area and looking at what is behind it. That is fifteen minutes of work and it decides a five figure question.
We will do that look for free, show you the photos, and tell you plainly which side of the line your house is on. Sometimes the answer is that you have another decade and you should keep your money. See how we handle siding and rot repair, or book a walkthrough.