Siding has two jobs. The one everyone sees is the look of the house from the street. The one that matters is keeping water and wind out of the walls. Siding can be ugly and still doing its job, and it can look fine from the curb while the sheathing behind it rots. Here is how to tell which you have.
Signs it has stopped protecting the house
- Warping and buckling. Panels that have pulled away from the wall, bowed or rippled no longer lap over each other, and water runs in behind.
- Cracks, holes and loose panels. A crack in vinyl or a split in wood is a direct path to the sheathing. A panel that rattles in the wind is one storm from coming off.
- Soft spots and rot in wood siding, or in the trim around windows and doors, which is usually where it starts.
- Bubbles under the paint on wood or fiber cement, which mean moisture is coming through from behind.
- Moisture inside. Peeling paint or wallpaper on an exterior wall, a musty smell, or mold near the baseboards on the weather side of the house.
- The heating bill. Siding that has lost its seal lets wind into the wall. If the house got draftier over a couple of winters and the windows are the same, look at the siding.
Signs that are only cosmetic
Fading on the sunny side is normal and does not mean failure. Chalking, the powdery film that comes off on your hand, is the finish breaking down and is a reason to plan, not to panic. A few dings from the lawn mower are patchable. Mildew in a shaded corner washes off. None of these mean the wall is wet.
The age question
Vinyl siding typically lasts 20 to 40 years depending on the grade and the exposure; the salt and sun on the South Shore shorten that. Wood lasts as long as it is kept painted, which is to say as long as someone keeps painting it. Aluminum goes on more or less forever but dents and fades. If your siding is near the top of its range and showing two or three of the signs above, replacing it on your schedule beats replacing it after a wall has been wet for a year.
Repair or replace
A few damaged panels on sound siding can be replaced, though matching the color on faded vinyl is hit and miss. Damage on one elevation, say the one that faces the bay, can sometimes be replaced as a wall. Widespread warping, cracking or rot is a replacement, and a replacement is the moment to put a proper housewrap and flashing behind the new siding, which is what actually keeps the wall dry.
Why a roofer
The places siding leaks are the places it meets something else: the roof, the windows, the doors, the foundation. Where a roof meets a wall, the step flashing behind the siding and the shingles on the roof are one detail. Because we do both, that joint gets done by one crew that owns the whole thing, rather than a roofer who stops at the wall and a sider who starts there.
If you are not sure which side of the line your siding is on, we will come and look. The estimate is free.
