JustBuild.World

GUIDE

Three ways to build a roof

Compare full-block steps, inward-facing stairs and a flat half-block roof using small examples built in JustBuild.

A roof changes the outline of a house even when the walls stay simple. Start with a small test building, inspect it from the side and keep a world-code backup before changing a finished house.

Full-block steps

A five-block-wide oak building under a stepped stone-brick roof, with a central ridge.
Full blocks make the layers easy to count. This example has a seven-block-wide first roof layer.
  1. Make walls five blocks wide and five deep, three blocks above the floor.
  2. Cover them with a seven-by-seven layer of Stone Bricks, overhanging each edge by one block.
  3. Add a five-block-wide layer above it, then three wide, then one. Keep every layer seven blocks long.
  4. Check that each higher layer moves inward by one block on both sides.

The layers are 7, 5, 3 and 1 blocks wide. An odd width leaves a single ridge; an even width leaves a pair at the centre. This method creates a solid roof. It is the same technique used in the starter house, at a larger width.

A stair roof

A pitched roof with stone-brick stairs rising from both sides toward a two-row ridge.
This example uses four-block-wide walls and six-block-wide eaves. The tall side of each stair faces the ridge.
  1. Choose Stone Brick Stairs in the block picker. Use walls four blocks wide and five deep.
  2. Start one block beyond the left wall. Place seven stairs in a row along the depth of the building, with their tall sides toward the centre.
  3. Repeat at the right edge, facing inward from that side.
  4. Move one block inward and one upward on each side for the next pair of rows. Repeat once more to meet at the centre.

Place temporary full blocks below the overhanging eaves and each higher row so there is a top face to click. Remove those supports after the roof is complete. Place the first row on top faces so the stairs stand upright. In JustBuild, the direction you face helps choose the stair orientation. Inspect one stair before continuing the row: its lower step should be outside and its tall side inside. Aim at the upper half of a side face or the underside and you can place an upside-down stair instead.

The roof cross-section has two stairs at the eaves, two a block higher and two at the ridge. The full vertical walls still finish below the eaves. Close the triangular end openings if you want a sealed interior; this example leaves them open so the roof shape is visible.

If a stair points the wrong way

Remove or undo that stair. Change the direction you are facing and try a single placement again. Adjacent stairs can form corners; check the end of a row before extending the roof around a bend. A small test is easier to repair than several completed rows.

A flat half-block roof

A thin, flat stone-brick half-block roof overhanging an oak building.
A lower-half roof gives a thinner edge than a full-block layer.
  1. Use a five-by-five building and choose Stone Brick Slab from the block picker.
  2. Place a half-block on a wall’s top face, then extend it into a seven-by-seven roof.
  3. When extending from a side, aim at its lower half to keep the new piece level with the lower-half roof.
  4. Inspect the edge from below and check that every piece is at the same height.

Placing on the upper half of a side can create a higher piece. Adding the complementary half in an occupied cell can merge the two pieces into a full block, making the edge thicker. Undo that edit if you wanted the thin profile.

Try this on a copy of the modern house. Replace the roof layer rather than adding half-blocks above the existing full-block roof.

Choose by silhouette

Full-block steps are straightforward to count. Stairs make a finer slope but need orientation checks. A flat half-block roof makes a thin horizontal edge. Compare each from the same distance before adding chimneys, trim or another material.

See controls and first placements or back up your world before experimenting.