Method of building construction comprising the steps of: preparing a foundation for a building at a building site; providing an onsite mobile packaged production machine at the building site; providing part data relating to a building design to the onsite mobile packaged production machine; supplying wood to the onsite mobile packaged production machine; the onsite mobile packaged production machine providing building parts formed from the wood and based on the part data in the order of assembly; assembling the building parts on the foundation to form the building, wherein at least external walls including the said building parts include interior and exterior panels having a cavity therebetween; and providing foam insulation into the cavity between the interior and exterior panels. A building formed using the method of construction is also provided. Cutting apparatus and a liquid-laden foam filler for wall panels are also provided.