How to Build an Addition to the Back of a Two-Story House

Designing and building a two-story addition to your house is similar to building a single-story addition. But the increased size and height of a two-story addition makes them much more visible. How well the addition compliments the character of your house, and how it affects the look of your house from the street are key considerations.

Instructions

1

Check your area's building and planning regulations to determine the allowable building height and size of your addition. Your local planning code will set out rules as to how big an addition you can build, and obtain a public and private sewer and utility layout for your home if it is available.

2

Design the floorplan for your addition. Write down a list of room requirements for your addition to help identify what is necessary for your floor plan to work. Check that the floor heights between the existing house and the new addition are the same, otherwise you will have to allow for steps up or down into the addition. Working with an architect will help make your addition look and feel more cohesive with your existing house.

3

Design the exterior of the addition. Choose the type of siding or cladding to compliment your existing house, and locate windows on the exterior to match the window size and placement on your home. The simplest roof addition is a shed or flat roof; however, the character of these roofs may not suit your home. If you already have a pitched roof, a gable or hip roof, your addition will require more work and more cost, but your house may be more attractive in the end.

4

Engage a structural engineer to help design the foundations and structure for your new addition. If the floor level of your addition is dug into the earth, you will need a structural retaining wall designed as part of your new foundation. Avoid locating the new addition over buried sewer or plumbing lines if possible.

5

Obtain planning approval and building permits prior to starting the construction of your addition. Getting a permit ensures that the building work you are doing is legal; it also requires your building work be done according to the building code. This way, there won't be a potentially damaging legal situation when you decide to re-sell your home.