diff --git a/ui/build/ninja.go b/ui/build/ninja.go
index 835f820..cb41579 100644
--- a/ui/build/ninja.go
+++ b/ui/build/ninja.go
@@ -59,6 +59,7 @@
 		"-w", "missingdepfile=err")
 
 	cmd := Command(ctx, config, "ninja", executable, args...)
+	cmd.Sandbox = ninjaSandbox
 	if config.HasKatiSuffix() {
 		cmd.Environment.AppendFromKati(config.KatiEnvFile())
 	}