Frequently Asked Questions About Construction Costs. UPDATED


Note: Since we originally put this together, the market in Seattle has only continued to get more competitive and prices are reflecting that. We have updated some of our base cost assumptions below to reflect what we are seeing in the office at the moment. 

If you are thinking about building a new home or remodeling your existing home, one of the first things you want to know is how much is it going to cost. The correct, although unsatisfying answer is: it depends. Without having a finished design in hand, it is hard to get a good handle on the cost and a search for residential design costs rarely produces anything worth while. Over time we have come up with some good rules of thumb to start out with. Please note that these costs are specific to Seattle. Construction costs are very regional so, if you are looking to build somewhere else, costs will be quite different.

New Construction - $200 275/sqft and up. Cost per square foot is a very rough way to come up with an early estimates for new construction and most contractors dont' particularly like it as it makes the assumption that all spaces cost the same per square foot. That said, it is a usefull tool for homeowners just starting out. For a better early estimate, try asymetrical cost estimates where each space has a different cost per square foot.

Remodel – Cost per square foot doesn’t really do a good job at estimating costs for remodels. Kitchen remodel costs per square foot are substantially higher than basement remodels, while living room additions cost less than bathroom additions. We find that thinking about remodels as discrete pieces of work gives us the best early handle on costs. Here are some ranges for typical remodel work we have done in the past.

Kitchen - $40,000 – $100,000. Average costs - $70,000    $60,000 - 200,000. Average costs  $150,000

Basement - $50,000 - $150,000. Average costs - $75,000   $75,000 - $170,000. Average costs - $125,000

Second Story addition - $175,000 - $300,000. Average costs - $250,000  $200,000 - $400,000. Average costs - $275,000

The next thing to get a handle on is that actual construction costs, the bricks and sticks so to speak, are only a part of the total cost of a project. Admittedly, construction costs make up the majority of the total cost but it is often the other fees that surprise clients when they start in on the design process. As time goes on, the number of fees and different entities and professionals that need to be involved, in even a simple project, have grown quite a bit. Regulatory agencies now require more paperwork, consultants, fees and time than ever before. A simple 850 square foot mother in law cottage we are working on is going to require six different licensed professionals, not including the contracting team.

If you are building a single family residence in the Seattle area you will need the services of a Seattle architecture firm, structural engineer and a surveyor. Most likely, you will also need a geotechnical engineer, civil engineer and an arborist.  If you are doing a simple remodel, you may be able to get away with just the architect but often a structural engineer will be needed as well. More complex remodels or additions often need the previously mentioned consultants as well. Below is a proforma for a new single family residence in the Seattle area.

Hard Costs





2000sqft @ $275/sqft




est @ 10% of building

Sales Tax



Subtotal Hard Costs



Soft Costs


Design Fees



est @ 10% of Building+Landscape costs

Geotchnical Engineer Fees


  If needed

Structural Engineer Fees



Civil Engineer Fees



Drainage and grading (if needed)




Tree survey (if needed)




Property lines and topography (almost always needed)

Building Permit Fees



Paid to the city


Subtotal Soft Costs



Total Hard and Soft Costs




A note on our (architectural) fees. While each project is unique, a good rule of thumb is that the architectural fees will be between 8% and 20% of the total construction cost. Our experience in the building trades allows us to be more efficient than many firms and we generally find our fees end up closer to 8% - 15%. For the majority of our residential work we bill hourly and provide detailed estimates at the beginning of each project broken down into the particular phases of design.

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