Super compact piston door with button and pressure plate

Solution 1:

If you're willing to put the button on the bottom block, this isn't too hard. Try something like this:

Here's another shot from the top:

And here's one from the back:

When either the button is pressed or someone stands on the pressure plate, the door will open.

If you want the button to be at eye level, you can make a minor modification, as suggested in the comments:

This will allow you to move the button up one block, at the cost of two repeaters. Keep in mind that this will add a (very) small delay to the circuit, but considering it's a button, this might even be an advantage.

Solution 2:

I made my own design and it fits completely between a 3 wide wall.

Outside of your house, without wall.

Inside of your house, without wall.

Outside of your house, with wall, and door closed.

Inside of your house, with wall, and door closed

Inside of your house with wall, and door open (there is an item on the wood pressure plate)

Hope this helps, it fits completely inside a 3 wide wall.

Solution 3:

This is a piston door that I know how to make. It's fairly compact. It takes a 4-wide by 3-deep by 6-tall space half of the door for a one-way door, so a two-way, 3x2 piston door takes up a total space of 8x5x6.