diff --git a/build.gradle b/build.gradle
index c711d8eb974..0b19b98296b 100644
--- a/build.gradle
+++ b/build.gradle
@@ -8,7 +8,7 @@ ext.checkOutDir = "${buildDir.path}/checkout"
 ext.outputDir = "${buildDir.path}/docs"
 ext.githubBranch = "3.0.x"
 
-ext.explicitGrailsHome = System.getProperty("grails.home") ?: project.getProperty("grails.home")
+ext.explicitGrailsHome = System.getProperty("grails.home") ?: (project.hasProperty('grails.home') ? project.getProperty("grails.home") : null)
 ext.grailsHome = explicitGrailsHome ? file(explicitGrailsHome).absolutePath : "$checkOutDir/grails-src"
 
 configurations {