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Can I Build an Addition Onto My Home?

Space is limited, and it is common to outgrow your home over time. Whether you have a new baby joining your family, the kids have grown up and overrun the space, you want a master suite, or need to accommodate an aging parent, there are a variety of reasons why your home may not work for your current scenario. Building an addition to your existing home can leverage your accumulated equity and give you the space you need in the home and neighborhood you already love.

There are many factors to determine if building a home addition is feasible for your home and budget. Here are several factors to consider when thinking of adding to your home:

1. Lot Size or Lot Lines

foundation walls being set for home addition

Can your lot accommodate the added square footage of building an addition? While it may appear like you have the extra room to build up or out, can you make it work on your specific lot? Each jurisdiction has certain criteria that need to be met such as lot coverage, floor area ratios, as well as building heights and setbacks.

Other overlays such as nature preserves, waterways, resource protection zones, wildlife habitats, and floodplains are other considerations that may affect the possibilities with your property.

So, how do you figure out what is feasible for your specific lot? First, someone must go down to the city on a fact-finding mission, ask the right questions, and talk to the correct person to get those answers. The planner pulls up your address in their software and views the property lines and associated overlays that may affect the property. They will talk to you about what you can do.

Our clients leverage the team at Mountainwood Homes to deal with the local jurisdictions and get the answers needed to come up with a great design plan that will work on their property.

2. Sewer, Water, and Power Connections

Home Utilities

Is your remodel project feasible with the current sewer, water, and power connections?

How are we going to connect the sewer to this new area?
Can you add a new bathroom to your existing water meter?

Figuring out these details is why the planning part of the project can take more time than you’d think. Get a professional involved to help think through these scenarios. Once we know the obstacles, we can design your space around any hurdles and costly circumstances.

3. Structural Feasibility


Home Addition Lot Size

We figure out whether an addition can be done and how the new room is integrated into the rest of your home.

An addition off to the side of the house seems easy to accomplish, but how does it attach to the house both aesthetically and structurally?

Does the existing foundation have the capacity for the additional load to be put on the structure? Early 1900s houses typically don’t support a second-story addition. We’ve come across some elaborate ways to make it happen with steel structures, but it’s not inexpensive. You can spend a lot of money in the basement before you get your addition built. This work is necessary, but no homeowner wants to spend more than they need to unless the benefit is there. You can do anything, but do you want to pay for it?

4. Accessing Your New Space

Modern interior staircase

What is access like? How is the connectivity to the new area? If you want to add to a wing of the house and create an addition onto the end of the hallway, how do you get to it? Your home was not originally planned that way. You don’t want to walk through a bedroom to get to the new area. How the rooms flow together is very important.

Few people realize how much space a set of stairs takes up to get you up to a second-story addition. “It’s about the size of your car,” says Robert Wood, president of Mountainwood Homes. “Visualize your car parked in that space. What space are you going to give up downstairs to get up there?”

Estimate that 50-75 square feet must come out of the existing footprint to get a staircase in.

5. Siding/Roofing/Windows

Charming home in Portland, OR

The best kind of home additions are the ones where you can’t tell which area is new; it blends seamlessly into the existing home. This does not happen by accident. Adding to your home requires thinking through the areas that are affected and figuring out what that will look like when it is done. Before you start on a home remodel, ask yourself if it is time to upgrade the rest of the home since it will be affected.

Often homeowners are not prepared for the snowball of cost with adding a new room onto their home because all these decisions roll into each other. We look at the structural side of things. During the planning stage of your home addition, we ask a lot of questions.

  • Are the siding materials even available? Will the new space blend in with the old?
  • Are the existing roofing materials available? Do you need to redo the whole roof?
  • Tired of your aluminum windows? Should you replace them all at the same time?
  • If a certain product isn’t available, are you okay with a similar suggestion?

With decorative trim in older homes such as the Laurelhurst area, do you want to match it exactly? If so, we will get a trim piece to match.

We’re picky. We want your new home addition to look beautiful. We aren’t afraid to speak up and let you know if we don’t think that the new addition concept will look good on your house.

6. Homeowners Associations


In some locations, you will have to get approval from the homeowners association to get approval for your remodeling project plan. A homeowners association (HOA) is an organization in a subdivision or planned community that makes and enforces rules for the properties and their residents.

HOAs are set up to protect the community, but you could find that you are restricted in more ways than you might assume. In addition to governing paint colors, CC&Rs may limit whether you can plant or remove trees and which types of products and materials you can use in your remodel.

In our area, there are longstanding homeowner associations as well as historic districts and design standards in Portland and many other jurisdictions. Not only do you have to get your project approved by the HOA, but the city gets involved along with neighbors if your home is in a historic or design district.

Want to build a home addition?

Building an addition is not simple. There are many behind-the-scenes steps involved with designing and building a home addition. All the details may seem overwhelming, but it is our job as your remodeler partner to help you figure it out. We will weigh the pros and cons, understand the limitations, and determine the costs associated with getting your project completed. This is also why we start with a design and feasibility agreement.

Mountainwood Homes is actively working in 10-15 different jurisdictions at any given time. We have the connections and experience to help you add more space to your home. If adding some extra space to your home will make you love where you live, then let’s talk! We’d love to help work through these details to determine if it makes sense to add on to your home!



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