diff --git a/lib/closure_tree/has_closure_tree.rb b/lib/closure_tree/has_closure_tree.rb
index b0bc5b1..4b19f78 100644
--- a/lib/closure_tree/has_closure_tree.rb
+++ b/lib/closure_tree/has_closure_tree.rb
@@ -11,7 +11,8 @@ def has_closure_tree(options = {})
         :dont_order_roots,
         :numeric_order,
         :touch,
-        :with_advisory_lock
+        :with_advisory_lock,
+        :order_belong_to
       )
 
       class_attribute :_ct
diff --git a/lib/closure_tree/model.rb b/lib/closure_tree/model.rb
index a3de39a..2ecb5be 100644
--- a/lib/closure_tree/model.rb
+++ b/lib/closure_tree/model.rb
@@ -171,6 +171,10 @@ def _ct_parent_id
       read_attribute(_ct.parent_column_sym)
     end
 
+    def _ct_belong_to_id
+      read_attribute(_ct.belong_to_column_sym)
+    end
+
     def _ct_quoted_parent_id
       _ct.quoted_value(_ct_parent_id)
     end
diff --git a/lib/closure_tree/numeric_deterministic_ordering.rb b/lib/closure_tree/numeric_deterministic_ordering.rb
index 4afe578..535b5dd 100644
--- a/lib/closure_tree/numeric_deterministic_ordering.rb
+++ b/lib/closure_tree/numeric_deterministic_ordering.rb
@@ -12,17 +12,17 @@ module NumericDeterministicOrdering
     def _ct_reorder_prior_siblings_if_parent_changed
       if public_send(:saved_change_to_attribute?, _ct.parent_column_name) && !@was_new_record
         was_parent_id = public_send(:attribute_before_last_save, _ct.parent_column_name)
-        _ct.reorder_with_parent_id(was_parent_id)
+        _ct.reorder_with_parent_id(parent_id: was_parent_id, belong_to_name: _ct.belong_to_column_sym, belong_to_id: _ct_belong_to_id)
       end
     end
 
     def _ct_reorder_siblings(minimum_sort_order_value = nil)
-      _ct.reorder_with_parent_id(_ct_parent_id, minimum_sort_order_value)
+      _ct.reorder_with_parent_id(parent_id: _ct_parent_id, minimum_sort_order_value: minimum_sort_order_value, belong_to_name: _ct.belong_to_column_sym, belong_to_id: _ct_belong_to_id)
       reload unless destroyed?
     end
 
     def _ct_reorder_children(minimum_sort_order_value = nil)
-      _ct.reorder_with_parent_id(_ct_id, minimum_sort_order_value)
+      _ct.reorder_with_parent_id(parent_id: _ct_id, minimum_sort_order_value: minimum_sort_order_value)
     end
 
     def self_and_descendants_preordered
diff --git a/lib/closure_tree/numeric_order_support.rb b/lib/closure_tree/numeric_order_support.rb
index 0223a41..a867216 100644
--- a/lib/closure_tree/numeric_order_support.rb
+++ b/lib/closure_tree/numeric_order_support.rb
@@ -13,38 +13,48 @@ def self.adapter_for_connection(connection)
     end
 
     module MysqlAdapter
-      def reorder_with_parent_id(parent_id, minimum_sort_order_value = nil)
+      def reorder_with_parent_id(parent_id:, minimum_sort_order_value: nil, belong_to_name: nil, belong_to_id: nil)
         return if parent_id.nil? && dont_order_roots
         min_where = if minimum_sort_order_value
           "AND #{quoted_order_column} >= #{minimum_sort_order_value}"
         else
           ""
         end
+        belong_to_scope = if parent_id.nil? && belong_to_id
+          "AND #{quoted_table_name}.#{belong_to_name} = #{belong_to_id}"
+        else
+          ""
+        end
         connection.execute 'SET @i = 0'
         connection.execute <<-SQL.squish
           UPDATE #{quoted_table_name}
             SET #{quoted_order_column} = (@i := @i + 1) + #{minimum_sort_order_value.to_i - 1}
-          WHERE #{where_eq(parent_column_name, parent_id)} #{min_where}
+          WHERE #{where_eq(parent_column_name, parent_id)} #{min_where} #{belong_to_scope}
           ORDER BY #{nulls_last_order_by}
         SQL
       end
     end
 
     module PostgreSQLAdapter
-      def reorder_with_parent_id(parent_id, minimum_sort_order_value = nil)
+      def reorder_with_parent_id(parent_id:, minimum_sort_order_value: nil, belong_to_name: nil, belong_to_id: nil)
         return if parent_id.nil? && dont_order_roots
         min_where = if minimum_sort_order_value
           "AND #{quoted_order_column} >= #{minimum_sort_order_value}"
         else
           ""
         end
+        belong_to_scope = if parent_id.nil? && belong_to_id
+          "AND #{quoted_table_name}.#{belong_to_name} = #{belong_to_id}"
+        else
+          ""
+        end
         connection.execute <<-SQL.squish
           UPDATE #{quoted_table_name}
           SET #{quoted_order_column(false)} = t.seq + #{minimum_sort_order_value.to_i - 1}
           FROM (
             SELECT #{quoted_id_column_name} AS id, row_number() OVER(ORDER BY #{order_by}) AS seq
             FROM #{quoted_table_name}
-            WHERE #{where_eq(parent_column_name, parent_id)} #{min_where}
+            WHERE #{where_eq(parent_column_name, parent_id)} #{min_where} #{belong_to_scope}
           ) AS t
           WHERE #{quoted_table_name}.#{quoted_id_column_name} = t.id and
                 #{quoted_table_name}.#{quoted_order_column(false)} is distinct from t.seq + #{minimum_sort_order_value.to_i - 1}
@@ -57,7 +67,7 @@ def rows_updated(result)
     end
 
     module GenericAdapter
-      def reorder_with_parent_id(parent_id, minimum_sort_order_value = nil)
+      def reorder_with_parent_id(parent_id:, minimum_sort_order_value: nil, belong_to_name: nil, belong_to_id: nil)
         return if parent_id.nil? && dont_order_roots
         scope = model_class.
           where(parent_column_sym => parent_id).
@@ -65,6 +75,7 @@ def reorder_with_parent_id(parent_id, minimum_sort_order_value = nil)
         if minimum_sort_order_value
           scope = scope.where("#{quoted_order_column} >= #{minimum_sort_order_value}")
         end
+        scope = scope.where(belong_to_name => belong_to_id) if belong_to_id
         scope.each_with_index do |ea, idx|
           ea.update_order_value(idx + minimum_sort_order_value.to_i)
         end
diff --git a/lib/closure_tree/support_attributes.rb b/lib/closure_tree/support_attributes.rb
index 38879ad..2741c29 100644
--- a/lib/closure_tree/support_attributes.rb
+++ b/lib/closure_tree/support_attributes.rb
@@ -36,6 +36,14 @@ def parent_column_sym
       parent_column_name.to_sym
     end
 
+    def belong_to_column_name
+      options[:order_belong_to]
+    end
+
+    def belong_to_column_sym
+      belong_to_column_name&.to_sym
+    end
+
     def name_column
       options[:name_column]
     end
diff --git a/spec/closure_tree/root_ordering.rb b/spec/closure_tree/root_ordering.rb
new file mode 100644
index 0000000..e2c8222
--- /dev/null
+++ b/spec/closure_tree/root_ordering.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+require "spec_helper"
+
+describe Block do
+  describe "correct root order_value" do
+    let!(:group) { Group.create!(name: "TheGroup") }
+    let!(:user1) { User.create!(email: "1@example.com", group_id: group.id) }
+    let!(:user2) { User.create!(email: "2@example.com", group_id: group.id) }
+    let!(:block1) { Block.create!(name: "1block", user_id: user1.id) }
+    let!(:block2) { Block.create!(name: "2block", user_id: user2.id) }
+    let!(:block3) { Block.create!(name: "3block", user_id: user1.id) }
+    let!(:block4) { Block.create!(name: "4block", user_id: user2.id) }
+    let!(:block5) { Block.create!(name: "5block", user_id: user1.id) }
+    let!(:block6) { Block.create!(name: "6block", user_id: user2.id) }
+
+    it "should set order_value on roots" do
+      assert_equal block1.self_and_siblings.pluck(:sort_order), [1,2,3]
+      assert_equal block2.self_and_siblings.pluck(:sort_order), [1,2,3]
+    end
+  end
+end
diff --git a/spec/support/models.rb b/spec/support/models.rb
index a49e013..9a60419 100644
--- a/spec/support/models.rb
+++ b/spec/support/models.rb
@@ -91,6 +91,13 @@ class ContractType < ApplicationRecord
   has_many :contracts, inverse_of: :contract_type
 end
 
+class Block < ApplicationRecord
+  acts_as_tree order: :column_whereby_ordering_is_inferred, # <- symbol, and not "sort_order"
+               numeric_order: true,
+               dependent: :destroy,
+               order_belong_to: :user_id
+end
+
 class Label < ApplicationRecord
   # make sure order doesn't matter
   acts_as_tree order: :column_whereby_ordering_is_inferred, # <- symbol, and not "sort_order"
diff --git a/spec/support/schema.rb b/spec/support/schema.rb
index cca75c5..2efc8de 100644
--- a/spec/support/schema.rb
+++ b/spec/support/schema.rb
@@ -9,6 +9,14 @@
     t.timestamps null: false
   end
 
+  create_table 'blocks' do |t|
+    t.string 'name'
+    t.references 'parent'
+    t.references 'user', null: false
+    t.integer 'sort_order'
+    t.timestamps null: false
+  end
+
   create_table 'tag_hierarchies', id: false do |t|
     t.references 'ancestor', null: false
     t.references 'descendant', null: false