diff --git a/XMonad/Layout/TwoPane.hs b/XMonad/Layout/TwoPane.hs
index 67bf9028..e478dcf5 100644
--- a/XMonad/Layout/TwoPane.hs
+++ b/XMonad/Layout/TwoPane.hs
@@ -56,8 +56,8 @@ instance LayoutClass TwoPane a where
 
     handleMessage (TwoPane delta split) x =
         return $ case fromMessage x of
-                   Just Shrink -> Just (TwoPane delta (split - delta))
-                   Just Expand -> Just (TwoPane delta (split + delta))
+                   Just Shrink -> Just (TwoPane delta (max 0 (split - delta)))
+                   Just Expand -> Just (TwoPane delta (min 1 (split + delta)))
                    _           -> Nothing
 
     description _ = "TwoPane"
diff --git a/XMonad/Layout/TwoPanePersistent.hs b/XMonad/Layout/TwoPanePersistent.hs
index f5898472..e7fa6a87 100644
--- a/XMonad/Layout/TwoPanePersistent.hs
+++ b/XMonad/Layout/TwoPanePersistent.hs
@@ -58,8 +58,8 @@ instance (Show a, Eq a) => LayoutClass TwoPanePersistent a where
 
   pureMessage (TwoPanePersistent w delta split) x =
     case fromMessage x of
-      Just Shrink -> Just (TwoPanePersistent w delta (split - delta))
-      Just Expand -> Just (TwoPanePersistent w delta (split + delta))
+      Just Shrink -> Just (TwoPanePersistent w delta (max 0 (split - delta)))
+      Just Expand -> Just (TwoPanePersistent w delta (min 1 (split + delta)))
       _ -> Nothing
 
   description _ = "TwoPanePersistent"