What Actually Happens During a Siding Installation, Day by Day

You have signed, or you are about to, and nobody has told you what actually happens next. What gets described in a sales meeting is the finished wall. Very little gets said about the week your house spends with its skin off. Here is the sequence, in order, and what each stage costs you when it gets skipped. Where a number here comes from James Hardie's installation instructions or from OSHA, you can hold a crew to it.

Before day one: the measure, the permit, and where the pallets land

The measurement that matters is not the one from the sales call. Before material is ordered, someone measures every elevation, counts every opening, and works out corner posts, trim widths, frieze runs and soffit lengths. That takeoff becomes a single order. A sloppy one surfaces mid-job as a reorder, and on a color-matched product that is not a same-day fix.

Permits are the part homeowners get wrong most often, usually because a blog told them the answer. Under 34 Pa. Code 403.62(a) a permit is generally required before you “construct, enlarge, alter, repair, move, demolish or change the occupancy of a residential building.” The Uniform Construction Code then excludes, at 34 Pa. Code 403.1(10), the “installation of aluminum or vinyl siding onto an existing residential or an existing commercial building, except as might be required by ordinances in effect under” sections of the act that preserve local ordinances. So vinyl sits outside the state code by default, while your municipality can still require a permit. Fiber cement is not named in that exclusion, and whether a Hardie re-side instead falls under 403.1(9), repairs to residential buildings, is a local code-official determination. We confirm with your borough or township and pull the permit where one is required. The answer in Lititz is not automatically the answer in Camp Hill, and anyone who answers without calling is guessing.

Material usually arrives before the crew, on pallets that do not move once set, so decide where they go in advance. Hardie's instruction is to store product flat, dry and covered prior to installation, because installing siding wet or saturated may result in shrinkage at butt joints. The tarp over the pallet is the difference between tight joints in year three and open ones.

Tear-off, and what is actually under your siding

Tear-off runs one elevation at a time, not all four at once. Old siding, old trim and whatever housewrap or felt sits behind it go into a dumpster or trailer. That is the first time anyone sees the real condition of the house.

The crew is looking for soft or delaminated sheathing, rot at window sills and the bottoms of corners, staining below roof-to-wall junctions where a kickout flashing was never installed, pest damage, and whether there is any functioning water-resistive barrier at all. On homes from the 1960s through the 1980s it is common to find tar paper in shreds, or nothing, or the old siding left in place under the newer layer. The substrate also sets what goes back on: HardiePlank installs over braced studs spaced a maximum of 24 inches on center, or directly to minimum 7/16 inch OSB sheathing. Sheathing too thin or too far gone to hold a nail is real money.

Rot is the honest change order. It cannot be priced through a closed wall, and an estimate promising no surprises is promising what it cannot know. Settle before day one how repair is priced, and who calls you before the work proceeds.

The water barrier and the flashing: the stage that decides how long the wall lasts

This stage photographs badly and takes a day nobody credits. It decides whether the wall is sound in twenty years.

Siding is cladding. It is not the water control layer. James Hardie says so directly: a water-resistive barrier is required in accordance with local building code, it must be appropriately installed with penetration and junction flashing, and “James Hardie will assume no responsibility for water infiltration.” The Vinyl Siding Institute says the same about its own product — vinyl, insulated vinyl and polypropylene siding are exterior claddings, not water-resistive barriers, and must be installed over a WRB to comply with current code. Whichever material you chose, the wrap and flashing behind it do the work. How that system fits together is covered in choosing between Hardie and premium vinyl.

Around openings, order is everything, because the system works by shingle-lapping so water drains down and out. The Department of Energy's Building America guidance and the Vinyl Siding Institute describe the same sequence: sill pan flashing first, then jamb flashing over the pan, then head flashing over the jambs and extending about an inch past them at each end, then housewrap over the head flashing last. ASTM E2112 is the standard practice it comes from. Reverse any two steps and you have built a funnel into the wall that looks perfect from the street.

Two pieces to watch for. Where a roof edge dies into a wall, a kickout flashing of minimum 4 inches by 4 inches throws runoff into the gutter instead of behind the siding; a missing kickout is often what rotted the corner we find at tear-off. Where a horizontal joint falls in the field of the wall, Z-flashing goes in with a minimum 1/4 inch gap above it that must not be caulked. The gap is the drainage path.

Hanging the siding

Installation starts with a 1-1/4 inch starter strip, which sets a consistent plank angle for every course above it. Minimum overlap is 1-1/4 inches. Clearances are published and not negotiable in HZ5, which is every ZIP code in Pennsylvania: minimum 2 inches at roof-to-wall, decks, slabs, paths and steps, 6 inches from grade to siding, and 1 inch from gutter to siding.

Blind nailing is Hardie's preferred method for HardiePlank. Face nailing is only for where code requires it in high-wind areas, and the two must not be combined on the same installation. For blind nailing the fastener goes on the nail line; where there is no nail line, between 3/4 inch and 1 inch from the top of the plank, and 3/8 inch from the edge.

Fasteners are driven perpendicular to siding and framing, snug and flush, heads against the siding with no air space. Hardie explicitly prohibits under-driving, over-driving, slanting, staples, clipped-head nails and aluminum fasteners. An over-driven nail in wood framing must be countersunk and filled, plus an additional nail added. Where nail depth is hard to set, Hardie's instruction is to pick a setting that under-drives and finish by hand.

Over-drive a nail and it crushes the board and stops holding. Under-drive it and it holds the next course off the wall. Both read from the ground as a wavy wall and surface years later as movement at the joints. Warranty coverage lives here too: Hardie publishes a 30-year non-prorated limited substrate warranty and a 15-year limited ColorPlus finish warranty, and improper installation is an explicit exclusion. The fastening schedule is the warranty.

Butt joints require one of three treatments code recognizes: joint flashing, which Hardie recommends, caulking, or an H jointer cover. An untreated butt joint is not permitted.

The cutting station, the dust, and the noise

Fiber cement is cut, not snapped, so a saw runs on your property most of the day, positioned so airflow carries dust away from the crew and your neighbors. Hardie ranks the methods, and the best of them is a circular saw with a HardieBlade and an attached vacuum dust collection system. Cutting indoors with a power saw is prohibited outright.

The rules here are OSHA's, not marketing. Table 1 of the respirable crystalline silica standard covers handheld power saws cutting fiber-cement board with a blade of 8 inches or less, outdoors only, with a dust collection system delivering the tool manufacturer's recommended airflow or greater through a filter of 99 percent or greater efficiency. Under that entry, required respiratory protection is “None,” both under and over four hours per shift.

The honest limit: OSHA notes that even with an effective system, some dust is still visible. It is controlled below the exposure limit, not eliminated. Expect a film on windows and sills, and keep them closed. Cleanup is wet or vacuumed, not swept: Hardie says never dry sweep the dust, and OSHA's housekeeping rule bars dry sweeping and compressed-air cleanup wherever a lower-dust method is feasible. The noise is a saw and pneumatic nailers through a working day.

Trim, caulk, and the joints that are supposed to stay open

Trim goes on as the field siding progresses: corners, window and door casings, frieze, and soffit and fascia where they are in scope. Exterior lights, hose bibs, dryer vents and meters come off, get mounted blocks, and go back.

Hardie requires all field-cut edges to be caulked, painted or primed, and ColorPlus field cuts to be edge-coated with a Hardie touch-up kit. Every plank cut on site has a raw edge, and every one left raw sits at a corner or an opening. That takes real time, which is why it disappears on a rushed job.

Just as important is what does not get caulked. Butt joints treated with flashing are not caulked, the minimum 1/4 inch clearance above Z-flashing is not caulked, and the clearances at roofs, decks, slabs and paths are not caulked shut. Caulk in a drainage gap turns a wall that drains into a wall that holds water, and the failure stays invisible from the street until it is expensive.

Touch-up paint is the one step that can honestly wait. ColorPlus touch-up goes on when the temperature of the air and of the siding products is above 40°F, and it must not be allowed to freeze. On a late-season job that can mean a return trip. It is cosmetic, not structural, and we would rather say so than paint in conditions the manufacturer excludes. More on what cold does and does not stop is in siding installation during a Pennsylvania winter.

What your week looks like from inside the house

You do not need to be home for most of it. Be there for the pre-start walk and the final walkthrough, and reachable by phone during tear-off in case something turns up in the wall.

• Your driveway is a job site. A dumpster or trailer, staged pallets and a cutting station take it. Park on the street the night before.
• Landscaping gets handled, within limits. Shrubs near the wall get tied back or trimmed so ladders can stand, beds get covered, and ladder feet still land in them. If a planting is fragile or means something to you, move it yourself first. “Be careful around the plants” is not an instruction anyone can follow.
• Take things off the walls, inside and out. Outside: hose reels, flags, address numbers, cameras, anything screwed to the siding. Inside: nailing vibrates exterior walls, so take down mirrors and pictures.
• Pets stay in, away from the working doors. Crews are in and out all day and gates get left open. It is the one item on this list that cannot be put right afterward.
• Your wall is not open overnight. Each section is torn off and dried in within the same working day. You are not sleeping behind bare sheathing.

How long it takes, and what makes a job run long

We are not going to print a day count. A number published before anyone has measured your house is a guess. Your schedule comes in writing with the estimate, after the home is measured. This is about days on site once the crew starts, not when a crew becomes available — a separate question, covered in why good siding crews book out early. What genuinely drives the calendar:

• Shape, not just size. Two-story walls, dormers, gables and bump-outs are far slower per square foot than long flat runs.
• Openings. Every window and door is a flashing sequence, not a cut. Thirty of them is a different job from fifteen.
• Material. Fiber cement is slower than vinyl for documented reasons: every piece is saw-cut with dust collection rather than snapped, planks are carried on edge and panels by two people, each course is blind-nailed into framing, and field cuts are sealed. None of it is optional. The tradeoffs are in the Hardie versus vinyl comparison.
• What tear-off finds. Sheathing and framing repair is the most common extension.
• Moisture. Product goes on dry, and self-adhered flashings need a clean, dry, frost-free substrate.
• Scope stacked into one job. Replacement windows during the re-side is the right sequence, because the flashing gets done once. It still adds days.

The variables that drive the schedule drive the price. Most full James Hardie projects in this market run $25,000 to $45,000 depending on home size, trim detail and tear-off, which is broken down further here.

The final walkthrough, and what to look at before you pay

Cleanup ends with a magnet sweep of the driveway, walks and lawn. Crews that skip it leave nails that turn up in tires weeks later. Gutters get checked for offcuts. Then walk all four elevations in daylight, before final payment.

• Clearances: about 6 inches from grade to the bottom of the siding, 2 inches at paths, slabs, steps and decks, 1 inch at gutters.
• A kickout flashing everywhere a roof edge meets a wall. If you cannot see one, ask where it is.
• The gap above any horizontal Z-flashing left open, not caulked.
• Butt joints flashed, caulked or covered, not simply butted.
• Field-cut edges at corners and around openings sealed or edge-coated, not raw gray.
• Nail heads: no dimples in the board face, and no proud heads holding a course off the wall.

Write the punch list down. A written list is normal, and easiest to resolve while staging is still on site. If you cannot get on a ladder, ask for photographs of the roof-to-wall junctions and the kickouts. Fortress carries a 10-year workmanship guarantee on full replacements, and the walkthrough is where anything that needs correcting gets named while it is cheap to correct.