The "halbstabe" houses seen in Germany and other places in northern Europe were made well into the 17th c., but I am not sure what the earliest example of one would be: certainly late medieval, but I don't know how far before the 14th c. As is often mentioned here, the middle ages covers a thousand years.

The frame of the house was built with timbers, a method now call timber frame construction. A log was worked square with a broad axe and an adze, then notched and shaped to fit in with other beams. Today, all these pieces would all be worked up ahead of time, and then the whole structure assembled in one short span of time: like for a barn raising, with lot of workers.

Of course, the frames have spaces in between. Today, for a barn those spaces are covered with sawn boards: in earlier days, they could be riven boards, overlapped to shed water. Today they're covered with some other more weatherproof paneling if humans are likely to be living inside. In the early days, though, a typical solution to filling the holes was what was called wattle-and-daub. A groove was cut into the beams, so that around the inside edge of every hole there was a groove. Flexible little pieces of wood about the size of your finger were than sprung into those , and woven across (Often these were shoots of ash or willow that were grown from stumps, a technique called coppicing). Once the kind of basketry ( the wattle) was woven across the openings , clay with straw, or with dung, or mud and straw, etc. ( the daub) could be applied over that and then let to dry. Over the clay could go plaster and/or whitewash, to keep the clay from being washed away by the rain. Here's a video showing the process.

At some point in time, the spaces between the beams could simply be filled by bricks, which could also be whitewashed. This is how many are found today.