Planning for Second Story Additions

If you have a small house or are just looking for some extra space in your home then you might want to consider second story additions. Second story additions are a fantastic way to get more out of your house, including installing en-suite bathrooms and even complete new rooms.

Deciding on the Purpose of the Extension

First thing's first, you need to decide what you intend to do with the space you will add to your house. Remember, if you are extending both floors then you will have to think about the effect on the ground floor too.

It's also important to think about how you will get to the newly added room. If you will have to go through one room to get to another then this is less than ideal. This also makes the room impractical and less useful than others. Planning carefully at this stage can help you to get the best value for money.


The foundations of your house were built to support a single story, you will need to call out a buildings inspector to check that your foundations are up to the job.

Planning on Paper

Thinking about how you want everything to look is all well and good, but you need to get something down on paper. This will not only make it possible to show people your design, but it also allows you to think about the design and to check that everything is correct. Draw everything to scale and ideally use a sheet of graph paper to do this or a computer drafting program. Properly drafted blueprints will likely be required by the local planning commission in order to get permits for construction.

Building Codes

The building additions need to be structurally sound, and any work done must conform to building codes. Apply for planning permission before breaking the ground, otherwise this could be an expensive risk which you don't even need to take. Check that you are allowed to build what you are proposing and that it won't affect your house.

Building codes will govern everything from the materials used, the methods of construction, the plumbing and even the electrical systems. The foundation, windows and insulation will also have to meet certain building codes.


You won't be able to build second story additions in all areas. The planning office may decide that it affects the look of the neighborhood, in which case it will not be permitted.


If you are installing a new bathroom or shower then you will need to think about how you are getting the pipes to their required location. The same will be true when thinking about electrical outlets. Most homes will only have one waste water down pipe for toilets, it will be easiest if the toilet is mounted directly above the others where possible.


When planning these second story additions it should be possible to estimate the cost required to complete the entire project. There are many different costs to factor in, including the cost of materials, labor and hiring professionals for any gas, water or electrical work. Generally the cost required to complete a second story addition will be much more than normal additions, the cost could be 30-50% more expensive.