diff --git a/example/lib/main.dart b/example/lib/main.dart
index ec66dac..9ad2c79 100644
--- a/example/lib/main.dart
+++ b/example/lib/main.dart
@@ -130,8 +130,8 @@ class Example2 extends StatelessWidget {
         itemBuilder: (context, index) {
           return StickyHeaderBuilder(
             controller: controller, // Optional
-            builder: (BuildContext context, double stuckAmount) {
-              stuckAmount = 1.0 - stuckAmount.clamp(0.0, 1.0);
+            builder: (BuildContext context, double? stuckAmount) {
+              stuckAmount = 1.0 - (stuckAmount ?? 0.0).clamp(0.0, 1.0);
               return Container(
                 height: 50.0,
                 color: Color.lerp(Colors.blue[700], Colors.red[700], stuckAmount),
@@ -201,8 +201,8 @@ class Example3 extends StatelessWidget {
           return StickyHeaderBuilder(
             overlapHeaders: true,
             controller: controller, // Optional
-            builder: (BuildContext context, double stuckAmount) {
-              stuckAmount = 1.0 - stuckAmount.clamp(0.0, 1.0);
+            builder: (BuildContext context, double? stuckAmount) {
+              stuckAmount = 1.0 - (stuckAmount ?? 0.0).clamp(0.0, 1.0);
               return Container(
                 height: 50.0,
                 color: Colors.grey.shade900.withOpacity(0.6 + stuckAmount * 0.4),
diff --git a/lib/sticky_headers/render.dart b/lib/sticky_headers/render.dart
index f83e58f..c2c798b 100644
--- a/lib/sticky_headers/render.dart
+++ b/lib/sticky_headers/render.dart
@@ -11,7 +11,7 @@ import 'package:flutter/widgets.dart';
 /// Called every layout to provide the amount of stickyness a header is in.
 /// This lets the widgets animate their content and provide feedback.
 ///
-typedef RenderStickyHeaderCallback = void Function(double stuckAmount);
+typedef RenderStickyHeaderCallback = void Function(double? stuckAmount);
 
 /// RenderObject for StickyHeader widget.
 ///
@@ -27,16 +27,19 @@ class RenderStickyHeader extends RenderBox
   RenderStickyHeaderCallback? _callback;
   ScrollPosition _scrollPosition;
   bool _overlapHeaders;
+  double _headerSpacing;
 
   RenderStickyHeader({
     required ScrollPosition scrollPosition,
     RenderStickyHeaderCallback? callback,
     bool overlapHeaders = false,
+    double headerSpacing = 0.0,
     RenderBox? header,
     RenderBox? content,
   })  : _scrollPosition = scrollPosition,
         _callback = callback,
-        _overlapHeaders = overlapHeaders {
+        _overlapHeaders = overlapHeaders,
+        _headerSpacing = headerSpacing {
     if (content != null) add(content);
     if (header != null) add(header);
   }
@@ -70,6 +73,14 @@ class RenderStickyHeader extends RenderBox
     markNeedsLayout();
   }
 
+  set headerSpacing(double newValue) {
+    if (_headerSpacing == newValue) {
+      return;
+    }
+    _headerSpacing = newValue;
+    markNeedsLayout();
+  }
+
   @override
   void attach(PipelineOwner owner) {
     super.attach(owner);
@@ -125,7 +136,7 @@ class RenderStickyHeader extends RenderBox
     headerParentData.offset = Offset(0.0, max(0.0, min(-stuckOffset, maxOffset)));
 
     // report to widget how much the header is stuck.
-    if (_callback != null) {
+    if (_callback != null && stuckOffset != 0) {
       final stuckAmount = max(min(headerHeight, stuckOffset), -headerHeight) / headerHeight;
       _callback!(stuckAmount);
     }
@@ -135,7 +146,7 @@ class RenderStickyHeader extends RenderBox
     final scrollBox = _scrollPosition.context.notificationContext!.findRenderObject();
     if (scrollBox?.attached ?? false) {
       try {
-        return localToGlobal(Offset.zero, ancestor: scrollBox).dy;
+        return localToGlobal(Offset(0, -(_headerSpacing)), ancestor: scrollBox).dy;
       } catch (e) {
         // ignore and fall-through and return 0.0
       }
diff --git a/lib/sticky_headers/widget.dart b/lib/sticky_headers/widget.dart
index ca639ef..fa9a03b 100644
--- a/lib/sticky_headers/widget.dart
+++ b/lib/sticky_headers/widget.dart
@@ -18,7 +18,7 @@ import './render.dart';
 ///  -1.0 >= value >= 0.0: past stuck
 /// ```
 ///
-typedef StickyHeaderWidgetBuilder = Widget Function(BuildContext context, double stuckAmount);
+typedef StickyHeaderWidgetBuilder = Widget Function(BuildContext context, double? stuckAmount);
 
 /// Stick Header Widget
 ///
@@ -33,6 +33,7 @@ class StickyHeader extends MultiChildRenderObjectWidget {
     Key? key,
     required this.header,
     required this.content,
+    this.headerSpacing = 0.0,
     this.overlapHeaders = false,
     this.controller,
     this.callback,
@@ -48,6 +49,9 @@ class StickyHeader extends MultiChildRenderObjectWidget {
   /// Content to be shown below the header.
   final Widget content;
 
+  /// Spacing between sticky header and start position.
+  final double headerSpacing;
+
   /// If true, the header will overlap the Content.
   final bool overlapHeaders;
 
@@ -60,21 +64,23 @@ class StickyHeader extends MultiChildRenderObjectWidget {
 
   @override
   RenderStickyHeader createRenderObject(BuildContext context) {
-    final scrollPosition = controller?.position ?? Scrollable.of(context)!.position;
+    final scrollPosition = controller?.position ?? Scrollable.of(context).position;
     return RenderStickyHeader(
       scrollPosition: scrollPosition,
       callback: callback,
       overlapHeaders: overlapHeaders,
+      headerSpacing: headerSpacing,
     );
   }
 
   @override
   void updateRenderObject(BuildContext context, RenderStickyHeader renderObject) {
-    final scrollPosition = controller?.position ?? Scrollable.of(context)!.position;
+    final scrollPosition = controller?.position ?? Scrollable.of(context).position;
     renderObject
       ..scrollPosition = scrollPosition
       ..callback = callback
-      ..overlapHeaders = overlapHeaders;
+      ..overlapHeaders = overlapHeaders
+      ..headerSpacing = headerSpacing;
   }
 }
 
@@ -91,6 +97,7 @@ class StickyHeaderBuilder extends StatefulWidget {
     Key? key,
     required this.builder,
     required this.content,
+    this.headerSpacing = 0.0,
     this.overlapHeaders = false,
     this.controller,
   }) : super(key: key);
@@ -102,6 +109,9 @@ class StickyHeaderBuilder extends StatefulWidget {
   /// Content to be shown below the header.
   final Widget content;
 
+  /// Spacing between sticky header and start position.
+  final double headerSpacing;
+
   /// If true, the header will overlap the Content.
   final bool overlapHeaders;
 
@@ -119,12 +129,13 @@ class _StickyHeaderBuilderState extends State<StickyHeaderBuilder> {
   Widget build(BuildContext context) {
     return StickyHeader(
       overlapHeaders: widget.overlapHeaders,
+      headerSpacing: widget.headerSpacing,
       header: LayoutBuilder(
-        builder: (context, _) => widget.builder(context, _stuckAmount ?? 0.0),
+        builder: (context, _) => widget.builder(context, _stuckAmount),
       ),
       content: widget.content,
       controller: widget.controller,
-      callback: (double stuckAmount) {
+      callback: (double? stuckAmount) {
         if (_stuckAmount != stuckAmount) {
           _stuckAmount = stuckAmount;
           WidgetsBinding.instance.endOfFrame.then((_) {