diff --git a/decorations/border.c b/decorations/border.c
index ac50c33..5868e88 100644
--- a/decorations/border.c
+++ b/decorations/border.c
@@ -76,7 +76,7 @@ verify_conf(keychain_t *chain, const struct yml_node *node)
 {
     static const struct attr_info attrs[] = {
         {"color", true, &conf_verify_color},
-        {"size", false, &conf_verify_int},
+        {"size", false, &conf_verify_unsigned},
         DECORATION_COMMON_ATTRS,
     };
 
diff --git a/decorations/underline.c b/decorations/underline.c
index a700bec..5b8bbd3 100644
--- a/decorations/underline.c
+++ b/decorations/underline.c
@@ -54,7 +54,7 @@ static bool
 verify_conf(keychain_t *chain, const struct yml_node *node)
 {
     static const struct attr_info attrs[] = {
-        {"size", true, &conf_verify_int},
+        {"size", true, &conf_verify_unsigned},
         {"color", true, &conf_verify_color},
         DECORATION_COMMON_ATTRS,
     };