something should be said of the way European infilled structures are designed. THere are, I see, 2 major classifications that might be used.

The first is the use of a frame designed specifically for the purpose. This would be like the German Fachwerkwand, where the entire framing system is originally designed around the use of brick and stone infills.

The other is the use of an all purpose frame modified to support infill. Basically this would be a studded timber frame where the weight of the structure is born by a few large timbers with small studs between them. This seems to be the prevailing style of England and France.

Which style is better? Well who is to judge> Both have proven themselves. The Germans claim that the true half-timbered frame originated with them and spread to the rest of Europe, this meaning the frame designed to support brick and stone instead of wattle and daub which is generally considered to e inferior by the Germans.

It is also important to note 1 thing about the infill. The Germans say that you should never expect the brick, stone, or whatever to have any structural properties whatsoever. You should not expect the infill to bear any of the roof load, or stiffen the frame, etc. even if it is made of high quality brick or well crafted masonry.

I have to ask about wattle and daub. If you have a frame system clearly designed to support an infill why bother with it?

The advantage of wattle and daub is that it can be made to cover as big an area as needed. You can build a house with a few posts and then set a series of stakes to build your wattle on, and so forth. Such is how early medieval houses were built.

But in Germany the half timbered structure was invented to get rid of the wattle, and use better materials instead such as brick, fired or unfired, and stone or even wood. I can't say for the development in other countries, as Germany is what I have studied, but I imagine the reason is similar.

So what would be the advantage of using wattle and daub? The Germans in the later middle ages occasionally used it to fill interior walls because it is obviously cheaper than nice bricks, but never trusted it on the outside.

The big advantage of bricks is that once they are there, they are there. They have been made in such a way that they are not going anywhere, especially if they are fired bricks.

The Germans have the following wisdom to offer on earthen wall materials:
The best material to use is a mixture of clay, silt, and sand. Too much sand makes it too lean and it crumbles, too much clay makes it too fat and causes it to crack and break apart. Straw is added and is not expected to serve as aggregate, but to alter the density. The addition of manure makes it stronger because of the mineral composition, also horse manure works the best as it has undigested cellulose fibers in abundance. Lime added to the mixture neutralizes acids in the mischt and produces preservative salts.

With all this, though, the general consensus among most Germans seems to be that brick is the best suited material for infill, and after that is stone. The infill is usually covered up with plaster at least on the outside, and often on the inside as well. The biggest reason would be that by so doing you can use cheap bricks, such as those from the outside of the old style kilns that aren't fired as well and have black all over them. The lime plaster covering protects the cheap bricks which would otherwise deteriorate quickly, and also hides their ugliness. In modern usage, this means you could go to a brickyard and buy their left-over bricks, bricks that were sent back as extras from orders. They are generally quite a bit cheaper and mismatched. but that doesn't matter if you are covering them up!

In France, it seems that in many cases instead of plaster gypsum is used. There is, after all, a reason why gypsum plaster is called plaster of Paris, as it used to come from mines in France.