diff --git a/lib/Slic3r/Print/Object.pm b/lib/Slic3r/Print/Object.pm
index e4e011960..cbee4359b 100644
--- a/lib/Slic3r/Print/Object.pm
+++ b/lib/Slic3r/Print/Object.pm
@@ -62,7 +62,9 @@ sub slice {
             my $support_material_layer_height;
             {
                 my @nozzle_diameters = (
-                    map $self->print->config->get_at('nozzle_diameter', $_), @{$self->print->support_material_extruders}
+                    map $self->print->config->get_at('nozzle_diameter', $_),
+                        $self->config->support_material_extruder,
+                        $self->config->support_material_interface_extruder,
                 );
                 $support_material_layer_height = 0.75 * min(@nozzle_diameters);
             }
@@ -76,11 +78,15 @@ sub slice {
                 );
                 $nozzle_diameter = sum(@nozzle_diameters)/@nozzle_diameters;
             }
-            my $distance = $self->_support_material->contact_distance($first_layer_height, $nozzle_diameter);
+            my $distance = $self->_support_material->contact_distance($self->config->layer_height, $nozzle_diameter);
         
             # force first layer print_z according to the contact distance
             # (the loop below will raise print_z by such height)
-            $first_object_layer_height = $nozzle_diameter;
+            if ($self->config->support_material_contact_distance == 0) {
+                $first_object_layer_height = $distance;
+            } else {
+                $first_object_layer_height = $nozzle_diameter;
+            }
             $first_object_layer_distance = $distance;
         }
     
diff --git a/t/support.t b/t/support.t
index 5967d5c69..3eba6e64b 100644
--- a/t/support.t
+++ b/t/support.t
@@ -1,4 +1,4 @@
-use Test::More tests => 26;
+use Test::More tests => 27;
 use strict;
 use warnings;
 
@@ -223,9 +223,9 @@ use Slic3r::Test;
     my $config = Slic3r::Config->new_from_defaults;
     $config->set('skirts', 0);
     $config->set('start_gcode', '');
-    $config->set('raft_layers', 3);
+    $config->set('raft_layers', 8);
     $config->set('nozzle_diameter', [0.4, 1]);
-    $config->set('layer_height', 0.3);
+    $config->set('layer_height', 0.1);
     $config->set('first_layer_height', 0.8);
     $config->set('support_material_extruder', 2);
     $config->set('support_material_interface_extruder', 2);
@@ -245,13 +245,17 @@ use Slic3r::Test;
             push @z, $args->{Z};
         } elsif ($info->{extruding} && $info->{dist_XY} > 0) {
             $layer_heights_by_tool{$tool} ||= [];
-            push @{ $layer_heights_by_tool{$tool} }, $z[-1] - $z[-2] if $tool == 0;
+            push @{ $layer_heights_by_tool{$tool} }, $z[-1] - $z[-2];
         }
     });
     
     ok !defined(first { $_ > $config->nozzle_diameter->[0] + epsilon }
         @{ $layer_heights_by_tool{$config->perimeter_extruder-1} }),
         'no object layer is thicker than nozzle diameter';
+    
+    ok !defined(first { abs($_ - $config->layer_height) < epsilon }
+        @{ $layer_heights_by_tool{$config->support_material_extruder-1} }),
+        'no support material layer is as thin as object layers';
 }
 
 __END__