A three-storey cottage: the same storey stacked three times on a 17 × 17 floor, under a dark oak hip roof that slopes in from all four sides. 24 layers, 2,750 blocks.
In the short, the cottage grows through three sizes — small (217 blocks), medium (840) and large (2,750). This pattern is the largest. Because every storey is the same, it is easier to read than its size suggests; the roof alone, though, is 1,041 blocks, 38% of the build.
Layer by layer — one storey three times, then the roof
LAYER 1 — floor. Fill 17 × 17 with 289 oak planks.
LAYER 2–5 — ground floor. LAYER 2 is a 59-cobblestone base plus furniture; LAYER 3 has plank walls with 16 glass between log posts; LAYER 4 is plank wall; LAYER 5 adds 16 glowstone. Log posts stand at the corners and mid-wall, 16 per layer.
LAYER 6 — second floor. Another 17 × 17 of planks, leaving a few cells open for the stairs.
LAYER 7–10 and 12–15 — second and third storeys. Repeat the ground-floor sequence twice; LAYER 11 is the third floor. Get one storey right and the other two are copies.
LAYER 16–24 — hip roof. LAYER 16 is a 19 × 19 eave, one wider than the walls on every side, edged with 72 dark oak slabs. Each layer above steps in by one on all four sides (15 × 15, 13 × 13 … 3 × 3) with dark oak stairs around the edge, and LAYER 24 is a single spruce plank on top.
How much wood?
1,251 oak planks is 313 logs; add 155 logs for the posts and you need about 468 oak logs. An oak gives 4–6 logs, so that is over 100 trees — replant saplings and run a tree farm while you build.
The roof takes 680 dark oak planks, 288 stairs and 72 slabs. Wooden stairs and slabs cannot be made on a stonecutter, so at a crafting table (6 planks → 4 stairs, 3 → 6 slabs) that is 1,148 planks, or 287 dark oak logs.
179 cobblestone, 48 glass and 46 glowstone are small next to the wood. 46 glowstone is 184 glowstone dust from the Nether.
Tips
After the ground floor, carry each log post straight up. A post that is off by one block is the first thing you notice from a distance.
Once the LAYER 16 eave is right, the rest of the roof is just stepping in one block per side. Check only the four corner stairs on the pattern.
Three storeys is a long fall. Build the LAYER 16 eave first and work from it, and carry a water bucket in survival.