diff --git a/.travis.yml b/.travis.yml
index 21d8946..916231d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -90,5 +90,6 @@ gemfile:
   - gemfiles/rails_4.2.3.gemfile
   - gemfiles/rails_4.2.4.gemfile
   - gemfiles/rails_4.2.5.1.gemfile
+  - gemfiles/rails_4.2.6.gemfile
 
 sudo: false
diff --git a/Appraisals b/Appraisals
index 4eaef59..338f280 100644
--- a/Appraisals
+++ b/Appraisals
@@ -85,6 +85,7 @@ RAILS_VERSIONS = %w(
   4.2.3
   4.2.4
   4.2.5.1
+  4.2.6
 )
 
 RAILS_VERSIONS.each do |version|
diff --git a/gemfiles/rails_4.2.6.gemfile b/gemfiles/rails_4.2.6.gemfile
new file mode 100644
index 0000000..b19415f
--- /dev/null
+++ b/gemfiles/rails_4.2.6.gemfile
@@ -0,0 +1,7 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "activerecord", "4.2.6"
+
+gemspec :path => "../"
diff --git a/lib/store_base_sti_class_for_4_2.rb b/lib/store_base_sti_class_for_4_2.rb
index f3317af..7d8ae23 100644
--- a/lib/store_base_sti_class_for_4_2.rb
+++ b/lib/store_base_sti_class_for_4_2.rb
@@ -1,3 +1,5 @@
+require 'active_record/associations/join_dependency/join_part'
+
 if ActiveRecord::VERSION::STRING =~ /^4\.2/
   module ActiveRecord
 
@@ -29,6 +31,72 @@ def creation_attributes
         end
       end
 
+      class JoinDependency # :nodoc:
+        class JoinAssociation < JoinPart # :nodoc:
+          def join_constraints(foreign_table, foreign_klass, node, join_type, tables, scope_chain, chain)
+            joins         = []
+            bind_values   = []
+            tables        = tables.reverse
+
+            scope_chain_index = 0
+            scope_chain = scope_chain.reverse
+
+            # The chain starts with the target table, but we want to end with it here (makes
+            # more sense in this context), so we reverse
+            chain.reverse_each do |reflection|
+              table = tables.shift
+              klass = reflection.klass
+
+              join_keys   = reflection.join_keys(klass)
+              key         = join_keys.key
+              foreign_key = join_keys.foreign_key
+
+              constraint = build_constraint(klass, table, key, foreign_table, foreign_key)
+
+              scope_chain_items = scope_chain[scope_chain_index].map do |item|
+                if item.is_a?(Relation)
+                  item
+                else
+                  ActiveRecord::Relation.create(klass, table).instance_exec(node, &item)
+                end
+              end
+              scope_chain_index += 1
+
+              scope_chain_items.concat [klass.send(:build_default_scope, ActiveRecord::Relation.create(klass, table))].compact
+
+              rel = scope_chain_items.inject(scope_chain_items.shift) do |left, right|
+                left.merge right
+              end
+
+              if rel && !rel.arel.constraints.empty?
+                bind_values.concat rel.bind_values
+                constraint = constraint.and rel.arel.constraints
+              end
+
+              if reflection.type
+                # START PATCH
+                # original:
+                # value = foreign_klass.base_class.name
+                value = ActiveRecord::Base.store_base_sti_class ? foreign_klass.base_class.name : foreign_klass.name
+                # END PATCH
+                column = klass.columns_hash[reflection.type.to_s]
+
+                substitute = klass.connection.substitute_at(column)
+                bind_values.push [column, value]
+                constraint = constraint.and table[reflection.type].eq substitute
+              end
+
+              joins << table.create_join(table, table.create_on(constraint), join_type)
+
+              # The current table in this iteration becomes the foreign table in the next
+              foreign_table, foreign_klass = table, klass
+            end
+
+            JoinInformation.new joins, bind_values
+          end
+        end
+      end
+
       class BelongsToPolymorphicAssociation
         private
 
@@ -231,6 +299,27 @@ def construct_join_attributes(*records)
 
       end
 
+      class HasManyThroughAssociation
+
+        def build_through_record(record)
+          @through_records[record.object_id] ||= begin
+            ensure_mutable
+
+            through_record = through_association.build(*options_for_through_record)
+            through_record.send("#{source_reflection.name}=", record)
+
+            # START PATCH
+            if ActiveRecord::Base.store_base_sti_class
+              if options[:source_type]
+                through_record.send("#{source_reflection.foreign_type}=", options[:source_type])
+              end
+            end
+            # END PATCH
+
+            through_record
+          end
+        end
+      end
     end
 
     module Reflection
diff --git a/test/test_store_base_sti_class.rb b/test/test_store_base_sti_class.rb
index 1e81361..821ebac 100644
--- a/test/test_store_base_sti_class.rb
+++ b/test/test_store_base_sti_class.rb
@@ -148,6 +148,13 @@ def test_polymorphic_has_many_through_with_double_sti_on_join_model
     assert_equal post, tagging.taggable
   end
 
+  def test_join_association
+    tag = SpecialTag.create!(:name => 'Special')
+    tag.polytaggings << Tagging.new
+
+    assert SpecialTag.joins(:polytaggings).where(id: tag.id).first
+  end
+
   if Gem::Version.new(ActiveRecord::VERSION::STRING) < Gem::Version.new('4.1.0')
     def test_finder_sql_is_supported
       author      = Author.create!(:name => 'Bob')