A brick clip to build double walls in a construction site, comprising a base from one face of which at least two projections capable of being inserted into the holes of a hollow brick are projected. The base is flat and has an X shape defining two right side arms and two left side arms. At each end of the arms of the X-shaped base a cylindrical projection protrudes, and at the center of the X-shaped base two parallel elongated projections protrudes. The cylindrical projections of the right side arms are inserted into the holes of one hollow brick, the cylindrical projections of the left side arms are capable of being inserted in the holes of another hollow brick, and the elongated projections are capable of defining a separation partition that keep the distance between the two bricks.

An adjustable support system has a base bracket member, a clip member, and an outer bracket. The base bracket member has a first end wall that overlays a substrate, a body wall extending outwardly therefrom and a second end wall opposite the first end wall. The clip member has a base bracket member coupling, and a projecting arm. The base bracket member coupling is attached to the first end wall and overlies a portion of the body wall. The projecting arm is spaceable apart from the body wall. The outer bracket has a spanning wall with inner and outer sides. An outer end wall extends from the outer side. The spanning wall is slidably positionable between the body wall of the base bracket member and the at least one clip member, to sandwich the same. Wall assemblies and methods are likewise disclosed.

Building blocks include a tongue and groove on each block that allow the blocks to be placed in a way that interlocks the tongue and groove of one block with the corresponding groove and tongue, respectively, of another block facing the opposite direction. In a first embodiment, the same building block that has a decorative front face is used for both sides of the wall, resulting in a wall with opposed finished surfaces. In a second embodiment, a first plurality of blocks that have a decorative front face are used for one side of the wall, while a second plurality of blocks that have a thicker and non-decorative face are used for the other side of the wall, with the first and second plurality of blocks interlocking back-to-back via their respective tongues and grooves. Both types of blocks can be made using the same concrete form.