A student asked a fascinating question in my Senior English class today: "What would the doors of Herot have looked like?" This was asked in conjunction with an assignment to draw Beowulf and his setting in your own interpretation. The student was trying to do a hyper realistic version.
We don't have any direct evidence that I know of. Longhouses or halls like Heorot no longer exist, so we depend on archaeological excavations. Often times, early medieval or Iron-Age sites have been destroyed either by modern ploughing or by modern urbanization. When we're lucky, we find floor levels and the postholes where the roof and wall supports went through the floor. Sometimes the posts themselves were removed for recycling, and sometimes they were left to rot in place.
Typically these postholes leave space for doors on the long sides, either in the center or closer towards the ends. Sometimes they match up with flagstones or cobblestones that were used to make a sort of patio outside. And in a very few instances, we've found the door ring apparently used to open and close the main door. So our best guess is that we'd have wood doors—possibly carved—made from lumber hewn with axes (no saws in the Iron Age!) and made functional with iron fittings.
We do have a few Scandinavian halls from the period that generated the Beowulf legend (although the Anglo-Saxon poet might reasonably have been imagined a more familiar Anglo-Saxon hall instead). In particular, there's Lejre (LIE-ruh) in Denmark, and Uppåkra (oo-POE-kruh) in southern Sweden.
If you search for Land of Legends (D. Sagnlandet), you'll find some of the reconstructions they've made for Lejre. For Uppåkra, they've haven't made any physical reconstructions, but they've done a good number of visualizations. And since Uppåkra is still periodically excavated, you can get a sense for what the archaeological remains are behind these reconstructions. Check out Uppåkra on Facebook or on its English homepage.
As a side note, Lejre has been working on a new reconstruction and they've been trying to get the right color palette. They worked with the National Museum of Denmark to recover paint samples from a few surviving scraps of wood, identify the underlying chemistry, and use that to mix pigments. You can see the colors here (check out the slide bar interactive that lets you paint a room in Viking colors!). I previously translated the Danish here.
