The tool asks five questions and turns your answers into a weighted score across three outcomes: repair, reside, and replace. It’s not a simple decision tree with one branch per question — several answers interact with each other, because that’s how a real inspection works. A contractor doesn’t decide “repair” just because damage looks isolated; they also check how old the siding is and whether that same spot has already been patched before.

Under the hood, each answer adds or subtracts points from all three outcomes at once. Extensive damage pushes the replace score up. Isolated damage on young siding pushes repair up. Any sign of moisture — soft spots, bubbling paint, a musty smell, warping on an interior wall — adds a heavy weight toward replace regardless of what the other answers say, because moisture behind siding is a wall-assembly problem, not a surface problem, and a repair or overlay can’t see what’s happening underneath.

The five inputs, in order:

1. Extent of damage — isolated to one or two sections, spread across multiple walls, or covering the whole house.
2. Age of the current siding — under 15 years, 15–25 years, or over 25 years.
3. Moisture signs — soft or spongy spots, bubbling or peeling paint, a musty smell near an exterior wall, or interior wall warping.
4. Repair history — whether this section has already been patched once, more than once, or never.
5. Reason for looking into it now — storm damage, general wear, rising energy bills, an upcoming sale, or just being proactive.

Once every question is answered, the tool doesn’t just report the highest score — it applies one override rule first: if moisture signs are present and the siding is old, has been repaired more than once, or the damage isn’t isolated, the result is always replacement. That combination almost always means the problem is at the sheathing, and no amount of patching or overlay fixes something you can’t see.

It helps to know what’s behind each input, because the reasoning is closer to how an inspector actually thinks than it might look at first glance.

Extent of damage isn’t really asking “how much work is this,” it’s asking “is this a material problem or a maintenance problem.” Damage confined to one or two sections is usually maintenance-level — something hit the siding, a piece failed, one spot took more weather than the rest. Damage spread across multiple walls or the whole house points to the material itself reaching the end of its usable life, which repair can’t solve no matter how many individual spots you patch.

Age matters because every siding material has a service life, and once you’re past it, the odds of finding a second and third problem right after fixing the first one go up fast. The tool treats siding under 15 years as still well within its working life, 15–25 years as the zone where a case-by-case read matters most, and over 25 years as approaching or past the point where most materials are due for replacement regardless of visible condition.

Moisture signs are the single heaviest-weighted input, and deliberately so. Everything else in this list is visible on the surface. Moisture problems usually aren’t — by the time you can see a soft spot or smell must indoors, water has typically been getting behind the siding for a while. That’s why this input overrides the others: a repair or overlay treats the symptom without ever opening up the wall to check the cause.

Repair history is a proxy for “did the last fix actually solve the problem.” A section that’s been patched more than once usually means whatever caused the original damage was never addressed — the same failure keeps recurring. That pattern is a strong signal to stop patching and find out what’s actually happening underneath.

Reason for looking into it now carries the least weight of the five, but it still shapes the read. Storm or impact damage nudges toward repair, since sudden, isolated damage to otherwise sound siding is the textbook repair scenario. Rising energy bills with no other obvious cause nudge toward replace, since a compromised wall assembly is a common — and often overlooked — cause of a house losing conditioned air.

Repair means patching the affected section and leaving everything else alone. It’s the right call when damage is contained, the siding is reasonably young, there’s no sign of moisture, and this isn’t a section that’s already failed once before. It’s also the cheapest and fastest of the three paths by a wide margin — see the siding repair guide for what a typical repair job actually involves.

Residing means installing new siding over the existing layer, usually with furring strips to create a flat surface. It’s a middle path: faster and less expensive than a full tear-off, but it comes with a real trade-off — an overlay can’t catch or fix anything already going wrong behind the old siding, because nobody’s opening the wall up to look. The tool only points toward residing when there’s no moisture signal in your answers; if there is, residing gets ruled out for the same reason repair does. More detail is in the residing guide.

Full replacement means tearing the old siding off entirely, which is the only path that lets anyone actually see the sheathing, housewrap, and framing underneath before new siding goes up. It costs the most and takes the longest, but it’s the only option that can catch and fix a problem instead of building over it. The siding replacement guide covers what that process looks like start to finish.

The tool’s output is a starting point for a conversation with a contractor, not a substitute for one. A few things worth doing with your result:

• Bring the reasoning, not just the verdict. The tool shows you why it landed where it did — mention those specific points (age, moisture signs, repair history) when you talk to a contractor. It’ll help them focus their inspection on the right spots faster.
• Treat a “replace” result as a starting point for questions, not a done deal. Ask what they expect to find once the old siding is off, and whether their quote already accounts for the possibility of damaged sheathing.
• Treat a “repair” or “reside” result as conditional. Both assume there’s nothing hidden behind the current siding. If a contractor opens things up and finds evidence otherwise, that’s new information the tool didn’t have access to, and it should change the plan.

This diagnostic answers what kind of job you need. It doesn’t answer what it’ll cost or what material to use if you’re replacing — those are separate questions with their own tools:

Once you know whether you’re looking at a repair, an overlay, or a full replacement, the siding cost calculator turns that into an actual price range based on your square footage, material, and region. If your result points toward replacement or residing and you haven’t settled on a material yet, the siding material matcher ranks the materials that fit your climate, budget, and maintenance tolerance.

Used together, the three tools cover the sequence most homeowners actually go through: figure out what kind of job it is, figure out what it’ll cost, and — if it’s a replacement — figure out what to replace it with.