What Does a Room Addition Cost in 2026?

What does a room addition cost? Well, it depends on a lot of factors. But at Home Front we believe it’s best to provide as much guidance as we can before we both spend a lot of time on a detailed estimate, so we’ll try to provide some general guidance here. Of course, we’ll need to see your individual project in order to give you a real price, but this should help you think through budget. And if you want to take some photos of your project area and send to us, we can absolutely discuss ballpark pricing over the phone before we come for an onsite estimate. 

I’ll also say this: there’s hardly any reality in those “reality TV” remodeling shows – Jenn won’t let me watch them anymore because I keep yelling at the TV. But out of all the unrealistic things on those shows, the most unrealistic thing is the prices they quote. They’re often not even in the right category, so don’t pay much attention to what they tell you things cost.

Going into 2026, think in terms of a general ballpark of $250 per square foot for a finished living area. That would include foundation, roof, walls, lighting, paint and good-quality flooring. It would typically not include a kitchen or bathroom, so those would be extra on top of that cost.

A common case we get asked about is adding a nice master suite or mother-in-law suite to a nice home in the mid-cities. For example purposes, let’s say a 15×15 master bedroom, with a 10×15 bathroom and a spacious closet, approximately 500 square feet total. Cost of this is likely to end up between $150,000 and $180,000, depending on factors such as:

• Is the exterior brick or siding?
• How difficult is it to tie into the existing roof structure to get proper drainage?
• How can we tie into the existing plumbing for water supplies and proper drainage?
• How much grading is required for the foundation?
• What level of finishes are we using for the interior?

• Are we going out – building into the yard with new foundation and roof – or going up and adding a second story? We can do either. Going up usually costs a bit more.
• The smaller the room addition, the higher the cost per square foot, and vice versa. Under 400 square feet, expect cost per square foot to be a bit higher. Above 1000 square feet, it will likely be lower.
• If we are adding a bathroom or kitchen to the new space, we’ll need to examine where we can tie into the existing plumbing. There are a few different ways to do this, and for your particular project, one may save money vs. another.
• Is there capacity in your existing electrical panel, or is it maxed out?

Our designers work very closely with our estimators to get you a room addition that works with your style and budget. For a project of this scale, we really recommend that you have our designers build a 3D rendering of the addition, so you can see everything before we build it and so that you can finalize the details early. See our 3D rendering examples and read more about our interior design team and their process.