for example Vikings were burning their leaders and prominent warriors together with a boat, so one can imagine how the house may similarly serve as a funeral p

for example Vikings were burning their leaders and prominent warriors together with a boat, so one can imagine how the house may similarly serve as a funeral pyre for a family/village elder - they do mention human remains found in some cases. That would make especial sense if the building's lifetime was on the order of those 60-80 years, say due to the climate which was more wet in that area during that period. And fire would be a great way to demolish and disinfect the place as well as probably affect the ground in some advantageous ways (say deep dry the ground for foundation like purposes and kill off the bacteria/fungus/etc (and termites or whatever was in their place back then) up to some depth in the ground, and the resulting layer of ash and ceramic-ized clay serving as a kind of barrier) before building again - a settlement was found for example with 13 such layers.