A concrete wall pre fabrication for the easy assembly of walls for residential and commercial buildings. More specifically, there is an apparatus and method for enabling the outer form of a concrete wall to be more precisely assembled off site and then transported to the work site and assembled the wall in the proper place with appropriate rebar before filling the forms with cement or concrete material as disclosed in the specification and drawings of the invention and the related claims. Additionally, there is a need for a form spacer that efficiently attaches between the form walls with a more precise use of glue and stronger attachment to the form walls.

A modular building system, includes a modular building assembly, including a base mounting structure with first and second base angle brackets; a left receiving wall assembly, including a left primary wall assembly, and left front and left rear corner brackets; a right primary wall assembly, and right front and right rear corner brackets; and front and rear wall assemblies; and a platform with legs; such that the modular building assembly is positionable on a top surface of the platform.

A connector for a structural insulated panel includes a base, a pair of sidewalls extending substantially perpendicularly to the base and arranged spaced apart from each other, each sidewall including a rail portion. The connector also includes a body arranged between the pair of sidewalls and defining a first gap between a first sidewall of the pair of sidewalls and the body and a second gap between a second sidewall of the pair of sidewalls and the body. The first gap is adapted to receive a first edge portion of a first layer of the structural insulated panel and the second gap is adapted to receive a second edge portion of the structural insulated panel. The connector further includes a pair of tongues extending substantially parallel to an outer surface of the base and defining a pair of channels therebetween.