diff --git a/lib/uri/generic.rb b/lib/uri/generic.rb
index fce8a8a..cc131bd 100644
--- a/lib/uri/generic.rb
+++ b/lib/uri/generic.rb
@@ -90,7 +90,7 @@ def self.build2(args)
         elsif args.kind_of?(Hash)
           tmp = {}
           args.each do |key, value|
-            tmp[key] = if value
+            tmp[key] = if value.is_a?(String)
                 URI::RFC2396_PARSER.escape(value)
               else
                 value
diff --git a/test/uri/test_generic.rb b/test/uri/test_generic.rb
index 9006125..4fff536 100644
--- a/test/uri/test_generic.rb
+++ b/test/uri/test_generic.rb
@@ -16,6 +16,16 @@ def uri_to_ary(uri)
     uri.class.component.collect {|c| uri.send(c)}
   end
 
+
+  def test_build2_preserves_non_string_components
+    components = {host: "example.test", port: 8080, path: "/a b"}
+
+    uri = URI::HTTP.build2(components)
+
+    assert_equal("http://example.test:8080/a%20b", uri.to_s)
+    assert_equal({host: "example.test", port: 8080, path: "/a b"}, components)
+  end
+
   def test_to_s
     exp = 'http://example.com/'.freeze
     str = URI(exp).to_s