A one story addition ‘footprint’ will typically be defined by regulations with respect to side yard and rear yard setback dimensions, as well as a percentage of the lot size, along with a bonus percentage (for lots not located in hillside zone or coastal area). Therefore, the larger the property, the more square footage can be added.
If the site has a detached garage, this may affect the size and shape of the one story addition. For instance, typically a ten foot separation is required between the garage and the one story addition, thus possibly impacting the floor plan design of the addition.
Given our above regulations, a two story addition can be up to 75% of the square footage calculated for the total one story addition allowance. As with a one story addition, height and step back considerations are code parameters that would be of planning considerations, during the architectural phase of the Project.
The type of residential zone that the property is located in will dictate the percentages of the above considerations and is the starting point for these evaluations.
A typical family with mom and dad and two kids, will likely covet their backyard spaces, in different ways. Planning for needs such as a BBQ/eating area; pool; half court basketball; maybe soccer space; grass area for the dog; etc. should be considered.
In this case, a second story addition, especially if the lot does not have a lot of depth, would probably be the preferred option for a home expansion. As stated previously, yes it is more expensive than a one story addition, but sometimes there’s not a lot of choice.
Also, master planning this out door space for ‘adult entertaining’, while the kids are young or even when they are no longer at home, should be thought of. For instance, level changes; semi-secluded seating areas; outdoor bars; access to the kitchen; music/sound considerations relative to the neighbors as well; catering and trash capabilities; etc. should be planned out in a landscape architectural design appropriately.
As well, strategic planning/planting of trees; shrubs; flowers; etc. should be visualized for current and future growth in terms of privacy/maintenance/smell/sun screening/visual color/etc. In terms of natural resources, watering requirements/conservation along with the possibilities of home grown herbs/fruits/vegetables and compost recycling, can optimize the outdoor/living environment.