How would you configure this barn?

Here is another, more basic, free area planner:

http://print-graph-paper.com/virtual-graph-paper

I would have a hard time planning where I lose the whole length aisle, unless one end you can’t exit easily anyway, like there is a drop-off and no way to drive out and around thru there, or a perimeter fence that can’t be changed, or such.

40’ long and so is very small and that whole length aisle seems a waste of space, but still …
Maybe having two exits in the barn is not that important for airflow and traffic thru it where you are.
The barns like that I have seen could have used that other door, if nothing else for ventilation.
One had a big fan on that end where the aisle would end, but it was way not enough, air in the stalls still felt stale.

I wonder if fixing that barn where it can be expanded in length soon for those extra stalls and storage space would not make sense, since that is really crowding things in there to get it all in the current space.

As for an indoor wash stall, you don’t need a drain on the floor.
Many do fine with letting water out of the back into a little French drain of rocks.
Ours has held wonderfully to lots of traffic washing horses and tack.

Can’t do that if you have no aisle between those two big stalls that take up the entire end of the barn. Gotta make a choice between these two options, aisle/exit or no aisle/exit at that end of the barn.

My point here is, the “aisle” is “wasted space” under the roof area. Minimize it. Or eliminate it entirely, if you can. My favourate configuration would be dividing the area into four quadrants with a wall down the centerline spine of the building, and short walls installed at whatever dimensions you need, for a tack/feed room, grooming stall, hay storage, and communal horse shelter area. Each quadrant communicating with the other, through doorways. So a horse can be brought from the communal area, into the grooming stall, which communicates with the tack room, for grooming and tacking up. The “grooming stall” can be converted to a regular stall, if you need to isolate one horse with injury, or overnight, or for separate feeding. The hay storage communicates with the communal shelter, access for feeding horses. No aisle.
This requires that all your horses cohabit. Which is how we keep horses NOW. Bonuses are: no restriction of movement, less chance of impaction colic or foot problems, less stress for horses in a herd environment, more socialization. Less stall mucking since horses are not locked into stalls. Less manure production since less bedding required. No requirement for “turning out” and “bringing in” to stalls. Potential problems are possible injuries from social interactions, and communal feeding (unless one is separated into the single available stall- either the “special needs” horse, or the aggressive horse, or the timid horse. But if all your horses get along well, and all can eat together, this configuration has become my favourate. Lose the “stalls”. This is similar to what I have NOW. We built it this way. Communal equine living.

Outside wash rack for sure. Assuming it’s butted up against the exterior wall, It is VERY easy to retrofit it with a little roof and two walls in the future. It will give you much more room in the barn.

Assume that of of your horses will be injured at some point and need stall rest. I’d try to make at least one standard sized stall, or make easily removable walls for a double.

Personally, I’d use that overhang for a loafing shed (this is also a place to stash an extra horse overnight), and put up a hay storage shed. I have used three carports built by the same company for this purpose. They are perfect, and CHEAP! My 12 x 24 x 15 with three walls was under $2000 installed. I can get nine tons in it. No way could I match that with materials and paying for labor. They have it up in under an hour. Plus the metal is maintenance free, which wood is not.

I think that using the end of the barn for stall space instead of aisle is a great idea…but be sure to address ventilation and air flow. And I suggest a grill on the reduced stall fronts AND between those stalls. I’ve seen that configuration get pretty dark/claustrophobic in some barns.

If using the end of aisle for the two back stalls, here is one company that did just that.
The aisle looks to be only 8’ wide, which is enough, not needing room to drive thru the barn with vehicles.
They made it look very nice:

http://www.morandindustries.com/Horse-stalls.html

Not sure that having that much bigger stalls on the ends is worth losing that exit and airflow, but maybe it is with such little room in there.

For airflow you could easily install one of those fans like used in chicken, hog, & turkey barns. Some of them have one at each end (or 2 at each end depending on the length and width of the barn). They come in various sizes designed to move a specific amount of air in a specific amount of time. Many of them are also set on thermostats or timers so they don’t run all the time and pump out warm/cold air depending on the season.

I also think having different sized stalls sounds like a good idea. If you don’t plan on driving through the barn for any purpose, I’d recommend big stalls on the end furthest from the door at the end of the aisle. Maybe add windows to the end stalls for added light and/or ventilation. If you only have 3 horses right now, I’d design one side of the barn specifically for those three horses to have appropriate sized stalls. Then on the other side I’d do the tack/feed room, a decent sized stall beside it for grooming/regular use, and the stall at the end as wide as the other stall and the aisle combined. If you use a standard length, you could easily divide that stall into with a gate if necessary. However, as a double sized stall, it would be useful as a foaling stall, lay-up/recovery stall, or oversized stall for oversized horses.

I actually use round pen gates to create stalls in my husband’s dirt-floored ‘garage’. The building is 30’x40’ and I use less than half for 2 12’x12’ stalls and still have room for storage and a vehicle (ATV, small SUV, small tractor, etc). I have 3 ponies (13-2 HH, 12-2hh’, and an oversized mini yearling) that I’ve had in these stalls. With the open round pen gates they can reach and see each other, but since they live in a pasture together, i figure they’re pretty well socialized with each other. The ‘mini’ was in the same stall as the smaller pony. I actually divided the 24’ unevenly to give the 2 smaller ponies a slightly larger stall since they were together.