This exterior guard barracks is the first piece of my new castle to be built. Of course it didn't turn out exactly as I had planned, but it seems OK to me. The worst part is the pictures. I've gone through several dozen pictures, and these are the best of the lot. My digital camera has no manual focus or aperture settings, so if I don't let it use the flash, the pictures are all very dull and yellow. So, until I find a better solution, you'll have to put up with pictures that have flash glare on bright edges.
The barracks is a two storey wooden structure, built against the castle's outer curtain wall. Building this has shown me that even after acquiring lots of Megabloks grey bricks, I don't have enough for a full castle with curtain wall at this scale. Oh well. I've used brown "log" pieces for the walls of the structure, with a two-layer footing of grey stone. There is also a one-layer thick stone floor. The second floor is a double-thick layer of black plates, with a network of 1xN black beams on the bottom of it. These beams sit on top of various pillars and supports, hopefully in a way similar to what would be done in real life. The caps of those supports are black tiles, and so the entire floor becomes one normal brick thick. The top roof of the building is done the same way, although it has fewer supports and beams.
When I first started building this structure (which I did a couple of times before getting this final version), I tried using the brown log wall pieces. I really dislike the unrealistic inner side of those, however. So, I tried using a double thickness log wall, using those wall pieces in a staggered pattern. That works, but ends up using about as many smaller log pieces as a single-thickness wall built without the wall pieces. The double thick wall is also harder to put windows in, and is more awkward to fit for corners, etc.
Since my goal has been to build something that structurally makes sense for the materials being modelled, I wanted to do the second floor as a series of beams resting on posts and wall supports, with cross beams on those to form the floors. However, Lego doesn't make odd-length beams longer than 3 studs, so I found myself not being able to fit things in properly. I could have expanded various dimensions to make even-length things work out, but I didn't like that option, especially since the vast majority of my black beams are 1x8. So, I finally gave up on full realism and simply assembled a network of beams on the bottom of the double layer of plates. Doing that takes the annoying bend out of the plates, and allows me to piece the beams together out of available lengths.
I tried a variety of things to provide light to the rooms. I ended up having very little luck using the flame pieces that Lego supplies. They are flames nearly as high as a minifig, and so don't make a lot of sense as torches, even though that seems to be their main purpose. I ended up using oil lamps on the lower floor, and low braziers for the upper floor.
There are still some unrealistic things about the basic structure. The wooden portions do not attach to the stone wall at all. I used that to be able to remove the stone wall, as you can see in some of the pictures. Is that realistic, or would there be ledges in the curtain wall, allowing beams and such to be attached? Similarly, the stone chimney is not attached to the wooden parts. This means that the back righthand wooden wall segment isn't attached to anything, and is therefore quite wobbly.
What would have happened here in real life, back in medieval times? Today, we would put metal strips in the joining concrete between the concrete blocks of the chimney, and the wooden (or metal) studs of the wall would be fastened to those. For a large solid concrete or stone wall, builders would use concrete nails, or would drill holes and place anchor bolts.