Sheet T-301 · Decision bench
Replace or repair? Answer six questions; read the reasoning, not just the verdict.
Age, damage share, moisture, and repair history decide most siding calls. This tool applies the printed table below and shows its working — including the cases where the only honest verdict is an in-person assessment.
Tool 01
The replace-or-repair bench
Answer all six questions
The verdict prints its reasoning only when every answer is in. Without scripts, use the decision table below — it is the same logic.
The decision table (works with no scripts, and in print)
| Situation | Proportionate answer | Why |
|---|---|---|
| Active moisture in wall; any damage share | Replace affected elevations; open and repair sheathing | Water inside the assembly outranks surface condition |
| Damage 50% or more of wall area | Full replacement | Patching a half-failed system costs replacement money in instalments |
| Past working life + damage 25% or more | Full replacement | Repairs buy little remaining service |
| Damage 10% or less; within working life; no moisture | Targeted repair + fix the flashing/caulk cause | Local failure, sound system |
| Everything between those rows | In-person assessment with a test opening | The deciding evidence is behind the siding |
Working lives used: vinyl ~25 years, fiber cement ~40, engineered wood ~30, wood ~20, stucco ~30 — in Atlanta humidity, with maintenance kept up. Neglected maintenance shortens every one of them.
The factors, one by one
Moisture intrusion outranks everything: a pretty wall with wet sheathing is a failing wall. Damage share is economics — past roughly a quarter to a third of the wall, mobilising repeatedly for patches approaches replacement cost. Age against working life tells you what a repair buys. Prior repairs expose patterns: the same corner failing twice is a flashing defect, not bad luck. Lead paint on pre-1978 painted siding does not decide repair versus replace, but it changes how either is done and what it costs — test first.