# Siding calculator

> 40′ × 25′ house, 2 stories: 22.7 squares of siding (+10% → 13 boxes), 3 rolls of house wrap, 31 pieces of J-channel and 8 corner posts. Squares of vinyl, fiber-cement or engineered-wood lap siding for your house, with house wrap, starter, J-channel, corners, trim and nails — from the same answers as the exterior paint Sheet.

## What to buy (40′ × 25′ house, 2 stories)

Every line shows the quantity to buy and how StudSheet got it: the spacing, the waste and the package size, so you can check it before the supply house or the quote.

| Buy | Material | How StudSheet counts it | What it is for |
|---|---|---|---|
| **13 boxes** | Vinyl siding (box of 2 squares) (boxes of 2 squares) | 2274 sq ft of siding (2340 sq ft of wall + 2 gables × 78 sq ft − 222 sq ft of windows and doors) + 10% + 5% more on the gables for the rake cuts = 2509 sq ft ÷ 200 sq ft a box. | A square covers 100 sq ft. Hang it loose so it can move. |
| **11 pieces** | Vinyl starter strip, 12 ft (12′) | 124 ft along the bottom of the walls (less the doors) + 5% ÷ 12 ft. | Nailed level along the bottom of the wall; the first course locks into it. |
| **31 pieces** | Vinyl J-channel, 12′6″ | 12 windows × 15 ft + 2 doors × 17 ft + 80 ft under the soffits + 55.9 ft up the rakes = 349.9 ft + 10% ÷ 12′ 6″. | Catches the cut ends of vinyl siding around windows and doors, under soffits and along rakes. |
| **8 posts** | Vinyl corner post, 10 ft (outside, 10′) | 4 corners × 2 (walls 18 ft tall, lapped every 10 ft). | Outside or inside corners for vinyl siding; lapped for taller walls. |
| **10 pieces** | Vinyl utility (finish) trim, 12′6″ | Under 12 windows (36 ft) and the top course under the soffits (80 ft) + 5%. | Holds the cut top course under windows and soffits. |
| **3 rolls** | House wrap, 9 ft × 150 ft roll (9′ × 150′) | 2496 sq ft of wall and gables + 10% for laps ÷ 1350 sq ft a roll. | The water-resistive barrier over the sheathing, lapped like shingles, top over bottom. |
| **3 rolls** | House wrap tape (for the seams) | A roll of tape per roll of wrap. | Seals the seams and the cuts in the wrap. |
| **3 rolls** | Window and door flashing tape, 4″ × 75 ft (4″ × 75′) | The sill, sides and head of 12 windows and 2 doors: about a roll per 6 openings. | Flashes the rough openings: sill first, then the jambs, then the head over the fin. |
| **6 boxes** | Siding nails, galvanized (box) (1¼–1½″ galvanized roofing nails, 5 lb box) | About 1 lb a square: 25.1 squares ÷ 5 lb a box. | Long enough for the sheathing plus any foam. |

### In Canada (12.19 m × 7.62 m house, 2 stories)

Set to Canada, the Sheet works the job out again for Ontario: metric sizes, bag sizes, the frost depth and the code notes. It doesn't just convert feet to meters. The first lines:

- **13 boxes, Vinyl siding (box of 2 squares):** 211.3 m² of siding (217.4 m² of wall + 2 gables × 7.3 m² − 20.6 m² of windows and doors) + 10% + 5% more on the gables for the rake cuts = 233.1 m² ÷ 18.6 m² a box.
- **11 pieces, Vinyl starter strip, 3.66 m:** 37.80 m along the bottom of the walls (less the doors) + 5% ÷ 3.66 m.
- **31 pieces, Vinyl J-channel, 3.81 m:** 12 windows × 4.57 m + 2 doors × 5.18 m + 24.38 m under the soffits + 17.04 m up the rakes = 106.65 m + 10% ÷ 3.81 m.
- **8 posts, Vinyl corner post, 3.05 m:** 4 corners × 2 (walls 5.49 m tall, lapped every 3.05 m).
- **10 pieces, Vinyl utility (finish) trim, 3.81 m:** Under 12 windows (10.97 m) and the top course under the soffits (24.38 m) + 5%.
- **3 rolls, House wrap, 2.74 m × 45.72 m roll:** 231.9 m² of wall and gables + 10% for laps ÷ 125.4 m² a roll.

## The steps, in order

> **PRO STEP: most of it is DIY-friendly; one step needs a licensed pro.** About 199–310 hours of work for this example.

1. Test the old siding for asbestos and the paint for lead first. Tear off: strip the old siding and trim, pull the nails, and replace soft sheathing.
2. Wrap: house wrap shingle-fashion from the bottom up, seams lapped and taped; flash every window and door — the sill first, then the sides, then the head.
3. Trim: snap a level line for the starter; nail the starter, the corner posts, and J-channel around the windows and doors and under the soffits.
4. Siding: lock the first course into the starter and work up, checking level every few rows; nail in the center of the slots, 16″ apart, heads 1/32″ off the vinyl so it can move, with ¼″ gaps at the channels (⅜″ below 40°F).
5. Gables: J-channel up the rakes, then cut each course to the rake angle and slip it in.
6. Finish: utility trim under the windows and at the top course; punch lugs in the cut top course and snap it in.

## Tools (20)

Must-have tools first, then the ones that help and the ones to rent for the day.

| Tool | Need | Why |
|---|---|---|
| **Scissor or boom lift** | Rent | The gables and upper walls: the highest point is about 24 ft up |
| **Frame scaffolding** | Rent | Or frame scaffolding along the high walls |
| **Pump jacks + planks** | Good to have | Pump jacks and planks climb the wall as the courses go up |
| **Extension ladder (28 ft)** | Good to have | Moving along the walls; a ladder of 28 ft reaches about 27 ft (Werner) |
| **Ladder stabilizer (standoff)** | Good to have | Holds the ladder off the new siding |
| **Step ladder (6 ft)** | **Must have** | First-floor courses and trim |
| **Chalk line** | **Must have** | A level line for the starter |
| **4-ft level** | **Must have** | Checks plumb and level over a long span. |
| **Tape measure (25 ft)** | **Must have** | The red boxes every 16″ on the blade are stud spacing. |
| **Utility knife + blades** | **Must have** | Scores drywall and vinyl plank, trims pad. Swap blades often. |
| **Aviation snips** | **Must have** | Cuts vinyl, J-channel and trim |
| **Snap-lock punch** | **Must have** | Lugs in the cut top course so it locks into the utility trim |
| **Siding zip tool** | **Must have** | Unlocks a panel to fix or remove it |
| **Circular saw** | Good to have | A fine-tooth blade, reversed, for stacks of panels |
| **Framing hammer** | **Must have** | Nails left 1/32″ loose |
| **Pry bar** | **Must have** | Old siding, trim and nails |
| **Roll-off dumpster** | Rent | About 4,549 lb of old siding (about 2 lb a sq ft for wood or fiber cement, less for vinyl): a 20-yard roll-off |
| **Safety glasses** | **Must have** | Every cut, every nail, every time. |
| **Work gloves** | **Must have** | Tack strip, block and lumber shred hands. |
| **Half-face respirator (P100)** | **Must have** | Old paint and dust in the tear-off |

## Mistakes and how the math works

### Mistakes that cost a callback or a second trip

- **Vinyl nailed tight:** It can’t move with the heat and buckles in summer. Nail in the slot centers and leave the heads 1/32″ off.
- **No gap at the channels:** Panels jammed into J-channel ripple when they grow. ¼″ at every channel and corner, ⅜″ in the cold.
- **Skipping the window flashing:** Water runs behind new siding at every window and rots the wall for years before it shows. Sill, sides, head — in that order.
- **Siding down to the dirt:** It wicks water and rots. Keep 6″ above the ground and 1–2″ off roofs and decks.

### What the calculator assumes

- House: 40′ × 25′, walls 18′ to the eaves (about 9 ft a story).
- Openings: 15 sq ft a window, 21 sq ft a door (the Exterior paint Sheet’s figures); gables half the width × the rise at 6/12.
- Waste: 10% on the walls, 5% more on the gables for the rake cuts.
- Vinyl in boxes of 2 squares; starter 12 ft, J-channel and utility trim 12′6″; corner posts 10 ft, lapped; nails about 1 lb a square.
- Windows trimmed with 15 ft of J-channel each (the sides, head and sill with laps), doors 17 ft.
- House wrap in 9 ft × 150 ft rolls (1350 sq ft), + 10% for laps; flashing tape about a roll per 6 openings.
- Staging by the highest point: a step ladder to 9 ft, an 8 ft ladder to 12 ft, scaffolding to 20 ft, then a lift.

## Code, permits and safety

The Sheet sets its code notes for the job's state or province. These are New Jersey's and Ontario's; the [code reference](https://studsheet.com/codes) has more. Always confirm with your building department.

- **Two stories: staging:** The walls run about 18 ft up and the gables to about 24 ft. Siding that high goes on from pump jacks and planks or scaffolding (a lift for the highest courses), two people to a course. Many homeowners hire the upper courses and the gables and do the first story themselves.
- **Test before you tear off:** Siding on older houses can be asbestos-cement shingles, common through the 1970s. Breaking them releases fibers, and many places require licensed abatement: have a chip tested first. Painted wood siding on a home built before 1978 may carry lead paint: test it first; if there’s lead, mist the boards and pry them off whole over plastic laid 10 ft out from the wall, bag the debris every day, and keep kids and pets away. EPA’s RRP rule doesn’t cover owners working on their own home, but anyone you pay must be lead-safe certified.
- **Code:** The IRC wants a water-resistive barrier behind the siding (R703.2) and flashing at windows and doors (R703.4). Vinyl goes on per its maker and the Vinyl Siding Institute’s manual; fiber cement and engineered wood per their makers’ guides.
- **No permit to re-side:** Repairing or replacing the siding on a one- or two-family house is ordinary maintenance in New Jersey: no permit (N.J.A.C. 5:23-2.7(c)(1)(xi)). Polypropylene siding is the exception and needs one.
- **Ask about a permit:** Re-cladding a house needs a building permit in some municipalities, especially with new sheathing or insulation. Ask your municipality’s building department. Confirm with your building department.

## Questions

### What materials do I need to install vinyl siding?

For the worked example, a 40′ × 25′ house, 2 stories, the Sheet counts 9 lines with waste included, starting with vinyl siding (box of 2 squares) (13 boxes), vinyl starter strip, 12 ft (11 pieces), vinyl J-channel, 12′6″ (31 pieces), vinyl corner post, 10 ft (8 posts). Each line's math is in the table above. Put in your own sizes in the [siding calculator](https://app.studsheet.com/p/siding) and every line is counted again.

### How long does it take to install vinyl siding, and can I do it myself?

About 199 to 310 hours for the worked example, in 6 steps. StudSheet stamps it **PRO STEP**: dIY with a pro for one step.

### What tools do I need to install vinyl siding?

20 in all. The must-haves start with step ladder (6 ft), chalk line, 4-ft level, tape measure (25 ft), utility knife + blades, aviation snips. On the Sheet you mark each one as owned, to buy or to rent.

## Ask about it

Stuck while you install vinyl siding? Ask in the [Siding group](https://studsheet.com/forum/siding) of the StudSheet community with this Sheet attached. Homeowners who've done it and verified pros answer, and anyone can read it.

## More roofing & siding Sheets

- **[Roofing, siding and gutters for contractors](https://studsheet.com/trades/roofing)**: run this takeoff at your own prices, send the estimate, and get it signed and the deposit paid.
- **[Shingle roof](https://studsheet.com/sheets/roofing)** (40′ × 30′ house, 6/12 roof): Squares, bundles, underlayment, ice barrier, drip edge, flashing, vents and nails for an asphalt shingle roof.
- **[Gutters and downspouts](https://studsheet.com/sheets/gutters)** (84′ of gutter, 4 downspouts): Gutter size, downspouts sized to the roof they drain, hangers, corners, end caps, outlets, elbows and extensions — sectional for DIY or seamless by the foot.
- **[All 45 Sheets](https://studsheet.com/sheets)**, across 16 trades.
- **[Code reference](https://studsheet.com/codes):** frost depths, guard heights, stairs, retaining walls.