2x4 Support For Stair Tread - Wood Cleat
I've never been a big fan of using two by fours to support stair
treads as a replacement for metal
brackets, because they have the ability to loosen up over time,
creating a safety hazard for anyone who walks up and down the stairway.
Don't get me wrong, I've seen these last for years and even decades, but when it comes to moving something heavy like a refrigerator up or down one of these stairways, with a couple of large men, handling the large object, I would want to be on it.
I don't even want to say it's common sense to use standardized construction methods, but really it is.
A lot of thought goes into most of our local building codes and teaching structural engineers and architects use specific types of construction methods and building materials and it will be to our benefit to follow these general practices or suffer the consequences.
Just because something like 2 x 4 wood cleats works sometimes, won't mean it will work all the time.