I will preface by saying that there are many ways to decorate interior dollhouse walls, some more time consuming than others. You can use scrap-booking paper to wallpaper your rooms, simply paint them, or add all manner of intricate plaster (or wood putty) decorative touches. This method is fairly simple and looks very finished when it is completed, though I chose to test it out in the bathroom first because it is so small--fewer coffee stirrers sticks to cut!
Where to Begin
First, your bare materials: I had a bag or two of wooden coffee stirrers available, though if you are going zero-spending on this project you could probably liberate some from an actual coffee shop--not that I am recommending that method! They are just as cheap as craft/popsicle sticks at Hobby Lobby or Michaels, though, and they have nice flat ends, so you only have trim one side to achieve the correct length and shape.
Once you have assembled your sticks, measure the interior wall of the dollhouse room to determine how high up the wall you want your wainscoting to go. I recommend dividing the height of the wall in half--if the wall is 10 inches tall, the wainscoting should be 5 inches tall.
Trim Coffee Stirrers to Desired Length
Trimming the coffee stirrers to measure exactly half the height of the interior wall can take a bit of time. First, measure your stick and mark when you want to cut with a pencil. Then, using a craft knife, score across the marking two or three times on each side of the stick. Then gently bend the stick on either side so it snaps along the channel you cut.
It is much quicker to use the first stick you trim as a measuring rod for the following sticks than it would be to measure each one. Just line up each following stick alongside the first one, score each side, and snap away!
I lightly sanded the snapped edge to soften the jagged edge, and also to ensure that all the pieces would line up to a uniform height for the later steps of this project.
How Many Coffee Stirrers Does It Take?
Measure the length of the interior wall. You will need enough coffee stirrers to fill that length. I kept a ruler on my cutting board and just lined up coffee stirrers along it until they added up to the length of the wall (which in my case was only 8 inches--as I said, the bathroom is very small!).
Create a Panel
You could conceivably attach your craft sticks to the interior wall one at a time, but making a mini panel by laying a piece of painter's tape across all of your sticks at once is much easier. I used two pieces of tape just to be safe, then flipped the whole panel over to spread wood glue along its back side. Don't go crazy with the glue or it will glop out the edges onto your wall, just spread a nice layer across the sticks, stopping short of the edges.
You could probably use craft or tacky glue for this step as well, but I am not sure how durable that option would be long-term, so I used wood glue.
Set Wainscoting In Place
This is the fun part! Using the loose ends of tape, pick up the wainscoting panel and gently press it, glue side down, against the wall. Smooth up and down from the floor to the top of the wainscoting to make sure it is firmly in place, and also to wipe away any bits of glue that may ooze through the coffee stirrers.
I found that the wood glue adhered quite well to the wall, but just in case I pressed the loose ends of tape around to the other end of the wall to keep everything in place while the glue dried.
Paint the Wainscoting
Before you start painting, as with any paint project, it's a good idea to tape over any surface you don't want to accidentally smear with wet paint. I used a bit more painter's tape along the top edge of the wainscoting to make sure I didn't get paint everywhere--you can see what happened to the floor, which I did not tape off! (I will be tiling that in a bit, so it didn't matter).
You could use pretty much any paint you have lying around for this: acrylics would work, or anything appropriate for a wooden surface. As it happened I had some trim paint left over from a real-person house project, so I used that. It's a bit glossier than I would have liked in retrospect, but it's clean and white and a nice contrast to the yellow walls.
You could just paint the top edge of your wainscoting and leave it at that. Or you could find these beautiful pre-cut miniature baseboards at your local Hobby Lobby, and glue that along the top edge! Amazon, Etsy, and most miniature stores offer a variety of options you can choose from. (If you are a woodworking expert and can make your own, even better!).
The Finished Product
Here it is! This was a fun project to begin the renovation of the dollhouse bathroom. It's a bit repetitive to measure and cut all the coffee stirrers, but the end result is worth it. Next up: tiling the bathroom floor!