Solidify issue

Hello everyone,

I’ve been working on a model which needs thickening, so naturally am using the solidify modifier. However, it’s either behaving strangely or my understanding of how it works needs improving! I’ve watched quite a few vids on YT but none have so far helped me figure out my problem. I’ve included an image demonstrating how the modifier is working currently, but it’s adding an internal thickness on one side and an external thickness on the other. What I’m aiming for is internal thickening only of all the sufaces of the model. Surely this is possible, or should I be using a different method?
If I tick the ‘even thickness’ option it creates a strange distortion at one corner, while the ‘clamp’ option doesn’t allow enough thickening.
I’ve checked the ‘origin to geometry’ option in case that was the problem, but no joy…
Can some knowledgeable person please help resolve my confusion here?
Many thanks indeed.

Check that all face normals are pointing consistenly, it feels like the normal on that middle face is pointing the wrong way.

You’re spot on Stan_Pancakes, solved my problem immediately. Many thanks indeed!