diff --git a/scenes/ui/build_drawer.gd b/scenes/ui/build_drawer.gd
index b53c32c..33b0721 100644
--- a/scenes/ui/build_drawer.gd
+++ b/scenes/ui/build_drawer.gd
@@ -14,12 +14,14 @@ class_name BuildDrawer extends CanvasLayer
 
 # ── layout constants ─────────────────────────────────────────────────────────
 const LAYER_ORDER: int = 16
+const PANEL_HEIGHT: int = 280  # fixed tray height — same for every tab
 const BTN_SIZE: int = 72      # preferred hit area for build buttons
 const FAB_SIZE: int = 48      # floating action button (open trigger)
 const TAB_HEIGHT: int = 36
 const LABEL_HEIGHT: int = 18
 const SECTION_HEADER_HEIGHT: int = 20
-const FLOW_COLS: int = 5      # buttons per row in the flow grid
+const SECTION_COLS: int = 3   # buttons per row inside one Build-tab section
+const FLOW_COLS: int = 5      # buttons per row in plain (non-sectioned) tabs
 
 # ── tab indices ──────────────────────────────────────────────────────────────
 const TAB_DESIGNATE: int = 0
@@ -100,20 +102,13 @@ func _build_ui() -> void:
 	_fab.pressed.connect(toggle)
 	root.add_child(_fab)
 
-	# Panel — auto-sized, anchored to the bottom-center of the screen.
-	# Width hugs the grid contents; height hugs the active tab's contents.
+	# Panel — full-width tray, anchored to the bottom of the screen.  Fixed
+	# height so switching tabs doesn't change the panel's footprint.
 	_panel = PanelContainer.new()
 	_panel.name = "BuildPanel"
-	_panel.anchor_left = 0.5
-	_panel.anchor_right = 0.5
-	_panel.anchor_top = 1.0
-	_panel.anchor_bottom = 1.0
-	_panel.offset_left = 0
-	_panel.offset_right = 0
-	_panel.offset_top = 0
-	_panel.offset_bottom = -8  # small gap from bottom edge
-	_panel.grow_horizontal = Control.GROW_DIRECTION_BOTH
-	_panel.grow_vertical = Control.GROW_DIRECTION_BEGIN
+	_panel.set_anchors_preset(Control.PRESET_BOTTOM_WIDE)
+	_panel.offset_top = -PANEL_HEIGHT
+	_panel.offset_bottom = 0
 	root.add_child(_panel)
 
 	var vbox := VBoxContainer.new()
@@ -192,62 +187,67 @@ func _build_designate_tab() -> Control:
 
 
 func _build_build_tab() -> Control:
-	var box := VBoxContainer.new()
-	box.name = "BuildTab"
-	box.add_theme_constant_override("separation", 4)
+	# Build tab is a row of three section columns (Structures | Furniture |
+	# Production), each its own header + grid.  Side-by-side layout fills the
+	# wide tray horizontally instead of pushing it taller.
+	var row := HBoxContainer.new()
+	row.name = "BuildTab"
+	row.add_theme_constant_override("separation", 14)
 
-	# Structures — walls, floors, doors.
-	_add_section_header(box, Strings.t(&"ui.build_drawer.section.structures"))
-	var structures := _make_flow_grid()
-	box.add_child(structures)
-	_add_tool_btn(structures, Strings.t(&"tool.build_wall_stone"), &"build_wall_stone",
+	# Structures — walls, floors, door.
+	var st := _make_section_column(Strings.t(&"ui.build_drawer.section.structures"))
+	var st_grid := st.get_child(1) as GridContainer
+	_add_tool_btn(st_grid, Strings.t(&"tool.build_wall_stone"), &"build_wall_stone",
 		func() -> void: _activate_wall(&"stone"))
-	_add_tool_btn(structures, Strings.t(&"tool.build_wall_wood"),  &"build_wall_wood",
+	_add_tool_btn(st_grid, Strings.t(&"tool.build_wall_wood"),  &"build_wall_wood",
 		func() -> void: _activate_wall(&"wood"))
-	_add_tool_btn(structures, Strings.t(&"tool.build_floor_wood"),  &"build_floor_wood",
-		func() -> void: _activate_floor(&"wood"))
-	_add_tool_btn(structures, Strings.t(&"tool.build_floor_stone"), &"build_floor_stone",
-		func() -> void: _activate_floor(&"stone"))
-	_add_tool_btn(structures, Strings.t(&"tool.build_door"),  &"build_door",
+	_add_tool_btn(st_grid, Strings.t(&"tool.build_door"),  &"build_door",
 		func() -> void: _activate(&"build_door",  &"", Strings.t(&"tool.build_door")))
+	_add_tool_btn(st_grid, Strings.t(&"tool.build_floor_wood"),  &"build_floor_wood",
+		func() -> void: _activate_floor(&"wood"))
+	_add_tool_btn(st_grid, Strings.t(&"tool.build_floor_stone"), &"build_floor_stone",
+		func() -> void: _activate_floor(&"stone"))
+	row.add_child(st)
+	row.add_child(VSeparator.new())
 
 	# Furniture — crate, bed, torch.
-	_add_section_header(box, Strings.t(&"ui.build_drawer.section.furniture"))
-	var furniture := _make_flow_grid()
-	box.add_child(furniture)
-	_add_tool_btn(furniture, Strings.t(&"tool.build_crate"), &"build_crate",
+	var fu := _make_section_column(Strings.t(&"ui.build_drawer.section.furniture"))
+	var fu_grid := fu.get_child(1) as GridContainer
+	_add_tool_btn(fu_grid, Strings.t(&"tool.build_crate"), &"build_crate",
 		func() -> void: _activate(&"build_crate", &"", Strings.t(&"tool.build_crate")))
-	_add_tool_btn(furniture, Strings.t(&"tool.build_bed"),   &"build_bed",
+	_add_tool_btn(fu_grid, Strings.t(&"tool.build_bed"),   &"build_bed",
 		func() -> void: _activate(&"build_bed",   &"", Strings.t(&"tool.build_bed")))
-	_add_tool_btn(furniture, Strings.t(&"tool.build_torch"), &"build_torch",
+	_add_tool_btn(fu_grid, Strings.t(&"tool.build_torch"), &"build_torch",
 		func() -> void: _activate(&"build_torch", &"", Strings.t(&"tool.build_torch")))
+	row.add_child(fu)
+	row.add_child(VSeparator.new())
 
 	# Production — workbenches + quarry.
-	_add_section_header(box, Strings.t(&"ui.build_drawer.section.production"))
-	var production := _make_flow_grid()
-	box.add_child(production)
-	_add_tool_btn(production, Strings.t(&"tool.workbench_carpenter"),
+	var pr := _make_section_column(Strings.t(&"ui.build_drawer.section.production"))
+	var pr_grid := pr.get_child(1) as GridContainer
+	_add_tool_btn(pr_grid, Strings.t(&"tool.workbench_carpenter"),
 		&"build_workbench_carpenter",
 		func() -> void: _activate(&"build_workbench_carpenter",  &"", Strings.t(&"tool.workbench_carpenter")))
-	_add_tool_btn(production, Strings.t(&"tool.workbench_smelter"),
+	_add_tool_btn(pr_grid, Strings.t(&"tool.workbench_smelter"),
 		&"build_workbench_smelter",
 		func() -> void: _activate(&"build_workbench_smelter",    &"", Strings.t(&"tool.workbench_smelter")))
-	_add_tool_btn(production, Strings.t(&"tool.workbench_millstone"),
+	_add_tool_btn(pr_grid, Strings.t(&"tool.workbench_millstone"),
 		&"build_workbench_millstone",
 		func() -> void: _activate(&"build_workbench_millstone",  &"", Strings.t(&"tool.workbench_millstone")))
-	_add_tool_btn(production, Strings.t(&"tool.workbench_hearth"),
+	_add_tool_btn(pr_grid, Strings.t(&"tool.workbench_hearth"),
 		&"build_workbench_hearth",
 		func() -> void: _activate(&"build_workbench_hearth",     &"", Strings.t(&"tool.workbench_hearth")))
-	_add_tool_btn(production, Strings.t(&"tool.workbench_cremation_pyre"),
+	_add_tool_btn(pr_grid, Strings.t(&"tool.workbench_cremation_pyre"),
 		&"build_workbench_cremation_pyre",
 		func() -> void: _activate(&"build_workbench_cremation_pyre", &"", Strings.t(&"tool.workbench_cremation_pyre")))
 	# Quarry — must be painted on a stone outcrop (BigRockNode); world.gd
 	# rejects placements on plain ground.
-	_add_tool_btn(production, Strings.t(&"tool.paint_quarry"),
+	_add_tool_btn(pr_grid, Strings.t(&"tool.paint_quarry"),
 		&"paint_quarry",
 		func() -> void: _activate(&"paint_quarry", &"", Strings.t(&"tool.paint_quarry")))
+	row.add_child(pr)
 
-	return box
+	return row
 
 
 func _build_stockpile_tab() -> Control:
@@ -301,9 +301,13 @@ func _make_flow_grid() -> GridContainer:
 	return g
 
 
-## Small section-header label between groups in the Build tab.  Drawn in the
-## panel's dark border colour so it reads as a divider rather than a button.
-func _add_section_header(box: Control, title: String) -> void:
+## One vertical section of the Build tab: header label on top, fixed-column
+## button grid below.  Returns the column (child 0 = label, child 1 = grid)
+## so callers can populate the grid with `_add_tool_btn`.
+func _make_section_column(title: String) -> VBoxContainer:
+	var col := VBoxContainer.new()
+	col.add_theme_constant_override("separation", 4)
+
 	var lbl := Label.new()
 	lbl.text = title
 	lbl.horizontal_alignment = HORIZONTAL_ALIGNMENT_LEFT
@@ -311,7 +315,15 @@ func _add_section_header(box: Control, title: String) -> void:
 	lbl.add_theme_color_override("font_color", MedievalTheme.C_PANEL_DARK)
 	lbl.add_theme_font_size_override("font_size", 13)
 	lbl.mouse_filter = Control.MOUSE_FILTER_IGNORE
-	box.add_child(lbl)
+	col.add_child(lbl)
+
+	var grid := GridContainer.new()
+	grid.columns = SECTION_COLS
+	grid.add_theme_constant_override("h_separation", 6)
+	grid.add_theme_constant_override("v_separation", 6)
+	col.add_child(grid)
+
+	return col
 
 
 const _THUMB_SCRIPT: Script = preload("res://scenes/ui/build_drawer_thumb.gd")