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You might like the idea of adding on space to your home but are not too sure of how much it will cost. Indeed, there can be so many questions about room additions

In this post, we give you some average costs for different types of additions so that you can start planning for your renovation budget. 

How much does an addition to your house cost? 

The cost of an addition depends very much on what you want. Bigger projects will cost more, as well as hiring an experienced contractor. The best way to make sure that you’re not paying too much is to get estimates from several different contractors. 

Additionally, the materials you use and finishings you choose, your house area, permits and the type of room addition you want will also affect the price. As such, it’s important to have a clear idea of the addition you want to have and a budget before you even start planning the renovations. 

Cost addition by size 

It’s hard to estimate the exact cost by size as there are so many other variables involved when it comes to price. 

However, the general average for a room addition is $80 to $200 per square foot. Thus, for a 10×10 feet room, you’ll have to have a minimum of $8,000, although it’s very likely that you’ll spend more. 

A 20×20 feet addition will naturally cost more than a 10×10. However, you might be surprised that the square foot price decreases. Additionally, the type of room addition you’re planning to have will also have to be factored in. 

Types of room additions

Here are some common types of room additions and the average costs.


A bedroom addition gives you significant space and adds comfort to your home. It may also increase your house value, though the ROI varies depending on factors such as area and quality. 

Bedroom additions vary depending on whether you want a simple room for the kids or a master suite with a full bathroom and closet. Price is dependent on the size (although the price increase is not linear to the size), materials and finishings used, and the construction method. 

For more on bedroom additions, read ‘How Much Does It Cost To Add A Bedroom To A House?’

Photo by Francesca Tosolini on Unsplash


A mudroom is usually located at the side or back entrance and serves as an informal exit or entrance to your home. It’s a place where you can store muddy boots and coats. Mudroom cost on average for 50 square feet is about $12,000. 

Laundry room

Some homes do not come with laundry rooms and if your washing machine and dryer are located in a small area of the bathroom or the kitchen, adding a laundry room is definitely a good idea! 

A laundry room can make your home more appealing and increase its value. Laundry room sizes are on average 35 square feet and cost about $8,500 and above. Moving the laundry room upstairs will cost you more. 


Kitchen addition and remodelling costs depend on factors such as whether you’re building from scratch, design and extent of the build. Custom kitchens will cost more. 

Also do remember that you will have to factor in demolition and removal costs if you’re looking at tearing out the old kitchen. 

For kitchen addition ideas, read ‘33 Kitchen Design Ideas You’d Want To Implement Immediately’.


Sunrooms are the perfect place for a cup of coffee and to relax. However, they don’t come cheap. Windows are costly, and if you’re planning on a four-season sunroom, you’ll have to consider heating and air conditioning, insulation and even plumbing. 

Sunroom sizes range on average from 80 to 240 square feet. Four-season sunrooms on average cost $45,000 while three-season sunrooms $25,000. 


If you’re considering a bathroom addition, be aware that they can become quite expensive. 

Plan ahead and be aware of what you need as changing design mid-build will result in an increase in expenses. The average bathroom additions are 48 square feet. Average cost of a normal bathroom is $200 to $300 per square foot, while luxury bathrooms cost $450 to $600 per square foot. 

Home Office

Home offices have increased in demand over the years as more people now have the flexibility to work remotely. A home office is an excellent feature to have if you need a conducive workspace at home. 

Home offices are usually 50 to 150 square feet and cost on average $100 to $200 a square foot. 

home office
Photo by Roberto Nickson on Unsplash

Bump-Out additions

A bump-out or micro addition is a common and economical way to increase your space. Because you’re bumping out a wall, you won’t need to add supports or foundation. Bump-out costs depend on the depth and length of the build, costing on average $85 to $210 per square foot. 


A garage addition is an excellent idea if your garage space is small or if your home came without one. The average two-car garage size is 400 to 576 square feet, and the average addition cost $35 to $60 per square foot. If you have a carport, you can save money by converting the carport into a garage, as there will already be a roof and a foundation. 

Second story

Adding a second story is a big project and can potentially double your living space. Building up is a great option if property lines are tight. It can, however, be expensive, with the average cost per square foot $100 to $300. Do make sure that you hire an experienced contractor as this is a complex addition. 

Labor costs to consider

Besides factors such as location, quality and complexity of the addition, labor cost will also affect the total price of your project. You will have to pay subcontractors in addition to your main builder. 

Have a look at the following components within labor costs:

  • Architect fees – $150 to $400 per hour
  • Plumbing – $45 to $200 per hour
  • Electrical works – $50 to $100 per hour
  • Foundation – $4 to $25 per square foot
  • Flooring – $3 to $22 per square foot
  • Roofing – $75 to $600 per square foot
  • Drywall – $1 to $3 per square foot
  • Windows – $40 to $50 per hour
  • Trim and siding – $2 to $5 per square foot

Other home addition cost factors

Besides labor costs, the final cost will also depend on the following:


You will need the relevant permits from your city or local authorities when building a home addition. This may cost you from $400 to $2,000, depending on your area. 


Materials such as paints, floors and finishings vary greatly. Obviously, better quality materials will be more expensive. You can try to save on the cost by purchasing them yourself, as your contractor will most likely either charge you for doing the shopping or mark up the material prices. 

Nonetheless, try not to skimp too much if you do have the budget, as good quality items will last longer. 

Demolition and excavation

Depending on what type of room addition you’re doing, you may need demolition and excavation services. Site preparation can cost from $1,500 to $5,000. Bigger projects such as adding a second story may even cost as much as $10,000. 


Room additions can be complex, and there is so much to do even before the actual renovation commences.

 If you’re wondering how to start and how much your room addition will cost, speak to us at Style & Structure

We’re able to advise and tailor to your needs if you would like to know how to stay within budget for room additions. It’s important to choose the right contractor if you don’t have the time and expertise to complete the project on your own.

We’re committed to excellence and take pride in a job well done. With years of experience as professional home remodeling contractors, you can be rest assured that we’ll do our best to turn your dreams into reality.

For room addition design inspiration, read ‘10 Room Addition Ideas for Small Homes’.