A building system includes a plurality of panels. Each of the panels includes a plurality of studs configured to serve as structural members and a polymeric block including a structural layer defined by the width of the studs and an offset layer. The offset layer extends in an interior direction from the structural layer. Upper and lower lengthwise notches may be included in the offset layer of the polymeric block. Non-structural elements are installed in the upper and lower lengthwise notches for use in mounting interior elements (e.g., wall cladding) to the interior side of the panels

Disclosed is a modular building construction having interlocking wall panels that mate with one another and with the frame of the building unit without screws, bolts or other fasteners, but while ensuring a water-tight fit. This configuration significantly simplifies installation of the wall panels into the skeletal frame of the modular building unit, allowing a first wall panel to be joined to an adjacent wall panel in a quick and easy installation step while maintaining the ability to later adjust and/or replace the wall panel.

A timber structural member includes: a first timber round having a first cooperating longitudinal surface, a second timber round having a second and a third cooperating longitudinal surfaces, and a third timber round having a fourth cooperating longitudinal surface. The first cooperating surface cooperates with the second cooperating surface, and the third cooperating surface cooperates with the fourth cooperating surface. The timber rounds are secured together to form a structurally integral unit in which the first cooperating surface is in contact with the second cooperating surface, and the third cooperating surface is in contact with the fourth cooperating surface, and the first, second and third timber rounds are substantially parallel to each other. The timber rounds are secured to each other by a plurality of spaced fasteners provided at acute and obtuse angles from a longitudinal axis of the structural member and extending through the timber rounds.

A building panel includes an insulating member having a first surface and a second, opposing surface, and a first sheathing member secured to the first surface of the insulating member and including a coupling portion. The coupling portion has a recessed portion, a first extension portion adjacent the recessed portion, and a second extension portion on the opposite side of the recessed portion from the first extension portion. A sum of a width dimension of the first extension portion and a width dimension of the second extension portion is substantially equal to a width dimension of the recessed portion, and at least one side surface of the insulating member is substantially coplanar with a respective side surface of the first sheathing member.

Building block for forming a wall construction, including insulating material and vertical load-bearing walls extending from one longitudinal side towards another longitudinal side of the building block, where the insulating material is provided with recesses for accommodating and holding the load-bearing walls in position, where inner part of the insulating material and the load-bearing walls are provided with recesses for accommodating at least one longitudinal reinforcing element binding the load-bearing walls together in longitudinal direction of the building block for forming an inner core where the vertical load-bearing walls, insulating material and the at least one reinforcing element together form the basic load-bearing in the building block, and that the building block includes at least one outer core formed by parts of insulating material and load-bearing walls outside the at least one reinforcing element, where the at least one outer core has supplementing and reinforcing properties for the inner core.