We built one and we bought a pre-made one and will be building a new one soon. The one we built was for our regular sized horses. 12 feet deep by 24 wide. It was in the middle of the pasture and used for shelter by day. We just framed it out with 2x4's, added panel siding (looks like individual boards but is in panel form), inside we lined with kick boards up about 4 feet. Roof was shingled. Three sides had walls and open front with one support middle post. The nice part about building was that we were able to work around the ground which was not flat by any means.<br><br>
The one I bought was very similar but smaller for my mini's and had doors in front. We removed the doors. 12 feet by 6 feet deep. It had a wood floor which I would not recommend for a run-in. I wanted the wood floors so I could mat it and use it like a stall if needed. That one we moved with us and is now a chicken coop.<br><br>
Do price out premade delivered ones. Depending on your location, sales and your time they can be very comparable in price.
We built our own, too. Check the direction of your prevailing winds before building. Even within our area, the winds can vary. Dh framed it with 2 x4s, framed the roof and we used plywood kickboard, plywood roof, tarpaper and shingles.<br><br>
You can also use metal for the roof and sides and put kickboard inside the metal. Good luck! Some of the prefab ones can collapse under a heavy snow load.<br><br>
We put rubber mats in them. Our ground isn't level, we were able to work around a slight slope by building it ourselves. I levelled the surface under the mats by hauling gravel. It's not perfect but works.