Renovating your home is a great way to keep living in the same place you have made tons of memories while also enhancing the aesthetics and functionality of the house. There are three main ways you can renovate a home, partially or fully renovating your home, and adding a new room to it. As with everything with remodeling, the timeframe of building a room is very important. So, how long does it take to build a room addition?

Usually, it takes about four months to add a new room to the house. But the timeframe isn’t a fixed one as a lot of things influence the time it takes to add a new room. The size and type of the room, the season, etc play a big role in determining how much time it takes to finish the project. 

Let’s take a detailed look a the time it takes to build a room addition. 

How long does an addition take to build

Adding a new room to your old house is a great way to add something new to the place you have been living in for years. It also increases the living space while increasing the value of the building, in case you want to sell it down the line. 

room addition preparation

But building a new room is a lengthy process and you need to take a lot of preparations for it, especially since you won’t be able to live in the house once the project starts. The case is different, though, for modular construction. 

Since you need to take adequate preparations for building a room addition, the time it takes to complete the project is extremely important. In general. It takes about four months to complete a 1000 square feet room. But this is by no means a fixed time frame because a lot of variables are at play that alters the time it takes to build a room addition to a house. 

Let’s take a look at how the building time of a room addition varies based on different factors. 

1. The size and the number of the room

The size of the room plays a big part in determining how much time it will take to build a new room inside the house. It is only natural that a room with a smaller size will take less time to be built than a bigger one. Also, it will take a lot longer to build multiple rooms than it will take to build only one. 

size of the room

2. The type of the room and its design

What kind of room you want to build also is a major factor in determining how long it will take to build a room addition. If you want a simple bedroom, you can get your work done in considerably less time than it takes to build a living room.

The design of the rooms is another key factor that influences the building tike. A room with intricate designs will take longer to build than a room with fairly simple designs. 

3. The work to be done

The time to build a new room depends a lot on how much work has to be done. If you are building a room from scratch, the contractor will have to lay the foundation, erect walls, install new wiring, etc to complete their work. This is a time-consuming process. 

work to be done

On the other hand, If you want a part of your house to be repurposed as a room, the work is significantly less than in the previous case. The contractor won’t have to lay a new foundation, nor they have to construct a new floor. They just have to tear down the wall, reroute the wiring and build a new room according to your design. 

4. Availability of the materials

Depending on what kind of material you are using for your new room, it can take different amounts of time to complete the project.

If you are using readily available materials, the time it takes to build a new room will be much smaller than what it will take to build a new room with high-end materials. This is because high-end materials are not available everywhere and they need some time to be cured. 

5. Getting paperwork

Getting renovation done involves a lot of paperwork. First, you need to come up with a plan and discuss it with your ADU contractor. Next, you have to make appropriate changes if your plan has any flaws in it.

Next, you have to obtain permits from the city council or whatever local authority is in charge of approving remodeling works. These things can take months to complete, which will only add to the time of the project. 

6. Season

The season during which you will renovate and add a new room to your house also plays a big part in determining how long it will take to complete the construction.

Make sure you don’t start your work during the rainy season and winter because you will not be able to have any work done at all. Summer is the best time to do any kind of renovation work, including adding a new room. 

Final Words

If you have never had any renovation work done in your home, it is only natural to wonder “how much time does it take to build a room addition?”.

The best way to ensure it doesn’t take too much time is to do extensive research before the construction work begins. Also, beware of contractors who set an unnaturally long time to finish the work, as they are mostly fraudulent and charge extra money due to the time they take. 


1. How much does a room addition cost?

The cost of a room addition depends o the dimensions of the room, among others. For example, the cost of building a 20×20 room varies between $42000 to $88000. So if you are wondering “how much does a room addition cost in California?”, you have to keep the dimensions of the room in mind. 

2. Do I need an architect for a room addition?

You don’t need an architect for a room addition. While it might come in handy during the process, you can do just fine without hiring an architect. 

3. How much does a 12×12 room addition cost

The average cost of building a new room is around $128. So, a 12×12 room will cost $18432. The cost will vary depending on a few factors, such as the material used to build the room.