diff --git a/lib/Slic3r/Extruder.pm b/lib/Slic3r/Extruder.pm
index 7ecafa186..eee0e2533 100644
--- a/lib/Slic3r/Extruder.pm
+++ b/lib/Slic3r/Extruder.pm
@@ -118,7 +118,10 @@ sub extrude_path {
     $gcode .= $self->unretract if $self->retracted;
     
     # calculate extrusion length per distance unit
-    my $s = $path->flow_spacing || $Slic3r::flow_spacing;
+    my $s = $path->flow_spacing
+        || $path->role eq 'support-material'
+            ? ($Slic3r::flow_spacing * 1.5)
+            : $Slic3r::flow_spacing;
     my $h = $path->depth_layers * $self->layer->height;
     my $w = ($s - $Slic3r::min_flow_spacing * $Slic3r::overlap_factor) / (1 - $Slic3r::overlap_factor);