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Adding a bedroom to your house is a big project. And as with all projects, budgets are always a concern. Here are some answers to frequently asked questions on cost estimates for bedroom additions

How much will adding a bedroom cost in San Diego and the Bay Area?

The cost of adding a bedroom depends on many factors. As such, you can expect to spend anywhere from $22,000 to $74,000, or even more. The cost of your room addition should include:

  • Basic shell and roofing costs
  • Standard windows
  • Drywalls and framing
  • Siding
  • Electric wiring
  • Plumbing
  • Interior stairs, if needed

You’ll have to ask your room additions contractor for a more specific estimate if you want to have custom made windows, special tiling, flooring, doors and other special fittings. Additionally, renovation costs generally do not cover appliances, cabinets, and vanities. 

The cost of adding a bedroom to your house will also be dependent on your region, the size of your addition as well as the materials and finishings you’re using. 

Master bedroom

Again, the price is largely dependent on the size of your addition, although the increase is not linear. Master bedrooms usually range from 200 to 400 square feet, while ensuite bathrooms are 50 to 200 square feet. 

The average cost to add a master bedroom is around $62,000 but can even go above $100,000. The average cost per square foot for master suite additions is $140.

Master bedroom additions generally have a higher price tag due to the better quality materials and special finishes chosen. Adding an ensuite bathroom will also obviously add to the cost. The good news is that master bedroom additions will usually get you a high return on investment. 

Basic bedroom

A simple basic bedroom of 10×10 feet can cost anywhere from $11,500 onwards. This, however, would be a bare-bones room without any built-in closets or ensuite bathrooms. 

Bedroom over garage

If you want a bigger space for a lower cost, consider building the room addition over the garage or porch. You’ll save on having to add on a foundation. Building a master bedroom over the garage will still cost you at least $50,000, but it’s significantly cheaper than building out. 

Converting attic to bedroom

Another way to add a bedroom if you’re on a tight budget is to convert the attic or basement. Nonetheless, you’ll still have to spend about $50,000 for quality materials and special finishings. However, this home improvement is likely to bring you a good ROI. 

attic bedroom


Photo by Francesca Tosolini on Unsplash

Cost of adding a bedroom per square foot

The average cost of adding a bedroom is $80 to $200 per square foot. If you have the money, it’s best not to skimp on quality. 

If you’re working on a minimal budget, read ‘Room Addition Costs: How To Stay Within Budget?

10×10 room addition

A 10x 10 bedroom addition would mean 100 square feet. Thus, the average cost would be from $8,000 to $20,000. However, note that a 100 square foot room is very small for a bedroom. 

12×12 room addition

A 12×12 room addition would mean that you’ll have a 144 square foot room. Again, using the average per square foot cost, you’ll have to budget on average $11,500 to $28,800. 

20×20 room addition

A 20×20 room addition means that you’ll have a 400 square foot room. Thus, the average cost would be $32,000 to $80,000. 

How much does it cost to add a bedroom with a bathroom to a house?

If you’re adding on a master bedroom, you’ll probably want to add a bathroom too. The cost of adding a bathroom varies depending on the work that needs to be done. Expect to pay more if you need to get plumbing, pipes and even water-proofing work done. Bathtubs prices alone will be a minimum of $700, while tub and shower combos are $3,000. 

Is it cheaper to build up or out?

The general assumption is that building up is cheaper than building out, as you do not have to lay a new foundation. While the price of building up can be as low s $100 to $150 per square foot, this is not always the best choice. 

Your house foundation can only withstand a specific load, and adding a second story means you may have to strengthen the foundations and existing walls. The cost of doing so may be comparable to laying a new foundation to build out. 

Additionally, you also need to consider bringing the electrical wiring and plumbing up to the second floor. 

However, building up may be your only option if your house is very close to the property line. One of the best ways to build-up is to do it over the garage, especially if your garage is built on a slab foundation as it is likely able to withstand the weight of the second floor. 

Do check local building codes and HOA rules before you start your project. 

What is the cheapest way to add a bedroom?

There is really no ‘cheapest’ way to add a bedroom – after all, you don’t want to compromise on the quality of your renovation. However, here are some ways in which you can add a room without breaking the bank:

  • Finish the unfinished basement or attic
  • Consider a bump-out addition
  • Add a sunroom
  • Add a room above your garage
  • Do some of the work yourself. For example, painting or shopping for finishings. 



Photo by Theme Photos on Unsplash

Is it worth it to add a room to a house?

Adding a room to a house is generally considered a good investment. However, the exact return of investment depends on factors such as your home location, type of room addition, as well as the construction quality and method itself. 

Can you remodel a bedroom yourself? 

Yes, you can DIY, if you have the knowledge, skills and tools to do it. This is especially true for simple projects like painting or replacing small fixtures.

However, it’s best to hire a professional for large-scale projects as they have the skill and experience to turn your vision into reality. 


The cost of adding a bedroom varies depending on numerous factors. For an accurate price estimate, contact us at Style and Structure. With years of room addition experience under our belt, your remodelling dreams are just a phone call away. There are ways to stay within budget which you could read further in our article Room Addition Costs: How to Stay Within Budget’. If you don’t have the time or expertise to complete the project on your own, it’s important to do research on how to choose the right contractor.

 Check out ‘10 Room Addition Ideas For Small Homes’ for room addition inspiration.