Cement

Choose an object that you can see within range that fits within a 15-foot cube—for example: a door, a section of wall, or a rope. You fortify the object, making it as hard as steel for the duration. Until the spell ends, the object's AC is 20 if it isn't already higher, and the object's hit point maximum and current hit points increase by 20.

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the object's hit point maximum and current hit points increase by an additional 10 for each slot level above 2nd.