diff --git a/packages/core/src/registry/handles.ts b/packages/core/src/registry/handles.ts
index 62ffc589..2d69058b 100644
--- a/packages/core/src/registry/handles.ts
+++ b/packages/core/src/registry/handles.ts
@@ -130,6 +130,8 @@ export type LinearResizeHandle<N> = {
   overrideTarget?: (node: N, sceneApi: SceneApi) => AnyNodeId | undefined
   min?: number | ((node: N, sceneApi: SceneApi) => number)
   max?: number | ((node: N, sceneApi: SceneApi) => number)
+  /** Snap the resized scalar to the editor's active grid step before apply. */
+  gridSnap?: boolean
   placement: HandlePlacement<N>
   /**
    * Dimension this handle steers (e.g. `'height'`). When set, the editor
diff --git a/packages/core/src/registry/types.ts b/packages/core/src/registry/types.ts
index c1ce0856..6013f5fd 100644
--- a/packages/core/src/registry/types.ts
+++ b/packages/core/src/registry/types.ts
@@ -541,6 +541,8 @@ export type FloorplanAffordance<N> = {
     nodes: Record<AnyNodeId, AnyNode>
     /** Initial pointer position in plan coordinates. */
     initialPlanPoint: FloorplanAffordancePoint
+    /** Active editor grid step in meters. */
+    gridSnapStep: number
   }): FloorplanAffordanceSession
 }
 
diff --git a/packages/editor/src/components/editor-2d/renderers/floorplan-registry-layer.tsx b/packages/editor/src/components/editor-2d/renderers/floorplan-registry-layer.tsx
index 716729ef..f27326f2 100644
--- a/packages/editor/src/components/editor-2d/renderers/floorplan-registry-layer.tsx
+++ b/packages/editor/src/components/editor-2d/renderers/floorplan-registry-layer.tsx
@@ -471,6 +471,7 @@ export const FloorplanRegistryLayer = memo(function FloorplanRegistryLayer() {
         payload,
         nodes: sceneNodes,
         initialPlanPoint,
+        gridSnapStep: useEditor.getState().gridSnapStep,
       })
 
       const snapshots: NodeSnapshot[] = []
diff --git a/packages/editor/src/components/editor/node-arrow-handles.tsx b/packages/editor/src/components/editor/node-arrow-handles.tsx
index 49463f80..c8bef3f3 100644
--- a/packages/editor/src/components/editor/node-arrow-handles.tsx
+++ b/packages/editor/src/components/editor/node-arrow-handles.tsx
@@ -12,6 +12,7 @@ import {
   nodeRegistry,
   type RadialResizeHandle,
   sceneRegistry,
+  snapScalar,
   type TapActionHandle,
   type TranslateHandle,
   useLiveNodeOverrides,
@@ -581,6 +582,10 @@ function LinearArrow({
         descriptor.axis === 'x' ? hitLocal.x : descriptor.axis === 'y' ? hitLocal.y : hitLocal.z
       const minBound = resolveBound(descriptor.min, Number.NEGATIVE_INFINITY, initialNode, sceneApi)
       const maxBound = resolveBound(descriptor.max, Number.POSITIVE_INFINITY, initialNode, sceneApi)
+      const gridSnapStep =
+        descriptor.kind === 'linear-resize' && descriptor.gridSnap
+          ? useEditor.getState().gridSnapStep
+          : null
       const factor =
         descriptor.kind === 'radial-resize'
           ? 1
@@ -615,7 +620,10 @@ function LinearArrow({
                 ? intersectionLocal.y
                 : intersectionLocal.z
           const delta = currentPointer - initialPointer
-          const next = Math.min(maxBound, Math.max(minBound, initialValue + delta * factor))
+          const rawNext = initialValue + delta * factor
+          const snappedNext =
+            gridSnapStep && gridSnapStep > 0 ? snapScalar(rawNext, gridSnapStep) : rawNext
+          const next = Math.min(maxBound, Math.max(minBound, snappedNext))
           return descriptor.apply(initialNode as never, next, sceneApi) as Partial<AnyNode>
         },
       }
diff --git a/packages/nodes/src/roof-segment/definition.ts b/packages/nodes/src/roof-segment/definition.ts
index 976466bf..71d64914 100644
--- a/packages/nodes/src/roof-segment/definition.ts
+++ b/packages/nodes/src/roof-segment/definition.ts
@@ -56,6 +56,7 @@ function roofSegmentWidthHandle(side: 'left' | 'right'): HandleDescriptor<RoofSe
     // 'max' = +X edge anchored (left arrow grows the -X edge outward).
     anchor: side === 'right' ? 'min' : 'max',
     min: MIN_ROOF_DIM,
+    gridSnap: true,
     currentValue: (n) => n.width,
     apply: (initial, newWidth) => {
       const rotY = initial.rotation ?? 0
@@ -100,6 +101,7 @@ function roofSegmentDepthHandle(side: 'front' | 'back'): HandleDescriptor<RoofSe
     axis: 'z',
     anchor: side === 'front' ? 'min' : 'max',
     min: MIN_ROOF_DIM,
+    gridSnap: true,
     currentValue: (n) => n.depth,
     apply: (initial, newDepth) => {
       // Recenter so the anchored Z edge stays at the same world point.
diff --git a/packages/nodes/src/roof-segment/floorplan-affordances.ts b/packages/nodes/src/roof-segment/floorplan-affordances.ts
index cbf7ab86..17e6b279 100644
--- a/packages/nodes/src/roof-segment/floorplan-affordances.ts
+++ b/packages/nodes/src/roof-segment/floorplan-affordances.ts
@@ -4,6 +4,7 @@ import {
   type FloorplanMoveTarget,
   type RoofNode,
   type RoofSegmentNode,
+  snapScalar,
   useScene,
 } from '@pascal-app/core'
 
@@ -56,7 +57,7 @@ function resolveSegmentFrame(
  * the math survives any parent-roof rotation.
  */
 export const roofSegmentResizeAffordance: FloorplanAffordance<RoofSegmentNode> = {
-  start({ node, payload, nodes, initialPlanPoint }) {
+  start({ node, payload, nodes, initialPlanPoint, gridSnapStep }) {
     const { axis, side } = payload as RoofSegmentResizePayload
     const segmentId = node.id as AnyNodeId
     const initialValue = axis === 'x' ? node.width : node.depth
@@ -79,7 +80,9 @@ export const roofSegmentResizeAffordance: FloorplanAffordance<RoofSegmentNode> =
       apply({ planPoint }) {
         const currentLocal = projectLocalAxis(planPoint[0], planPoint[1])
         const delta = (currentLocal - initialLocal) * side
-        const newValue = Math.max(MIN_ROOF_DIM, initialValue + 2 * delta)
+        const rawValue = initialValue + 2 * delta
+        const snappedValue = gridSnapStep > 0 ? snapScalar(rawValue, gridSnapStep) : rawValue
+        const newValue = Math.max(MIN_ROOF_DIM, snappedValue)
         lastValue = newValue
         useScene
           .getState()