Tying in an Addition to an Existing Home
Use these tips and tricks to match new floor heights to old and get everything square.
Synopsis: Building an addition can be tricky, especially when trying to match the height of the new floor to that of the existing structure. Builder John Whritner details his method of using a story pole and a builder’s level to determine the cripple-wall heights and get everything square and level. A detailed drawing and a series of photographs show the step-by-step process of laying out and building the cripple walls, adjusting as needed, and then tying it all together.
For a lot of reasons, building an addition can be trickier than building a new house. On this project, we needed to match the height of the new floor to that of the main floor of the existing structure, and the new foundation jogged and stepped, resulting in two different cripple-wall heights. Any difference in elevation from new floor to old would telegraph, so everything had to be spot on.