How to Extend a 4 Room House?

by | May 7, 2024


Are you thinking about adding more room to your 4-room house? Many people look for ways to make their homes bigger, whether it’s for a growing family, setting up a new home office, or just wanting a little extra space. Making your house bigger is not just about adding room; it can also increase the value of your home.

In this blog, we’ll show you different ways to extend your 4-room house. We’ll cover everything from the basics of adding on to your house to planning your design, managing your budget, and understanding the rules you need to follow.

Whether you’re dreaming of a bright new room or an extra bedroom, let’s explore how you can make your house the perfect fit for your needs!

What Are the Core Principles of House Extension?

House Extension
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When you think about making your house bigger, it’s like planning a big project. First, you need to know what you can and can’t do. This means checking the rules in your area about building. 

Some places have strict rules about how big or tall you can make your house. It’s also a good idea to talk to experts like architects or builders. They can help you understand what’s possible and what might be too hard or too expensive. Remember, planning well at the start can save you time and trouble later on.

What Are the Types of House Extensions Suitable for a 4-Room House?

Single-storey extensions 

This is when you add a room or two on the ground level. It’s a popular choice because it’s usually easier and less costly than building up. You could make your living room bigger, add a dining area, or even create a new bedroom. The key is to make sure the new part looks good in your existing house and uses space wisely.

Two-Storey/multi-storey extensions

If you need a lot of extra space, you might think about adding more than one floor. This is great for adding several rooms, like extra bedrooms or bathrooms. But it’s more complex than just a single-storey extension. You need to make sure your house can support the extra weight, and it usually costs more.

Conservatories and sunrooms

These are rooms with lots of windows, often made of glass. They’re perfect if you want a place to relax and enjoy the sun. They can be cheaper than a full extension and are great for enjoying your garden or backyard, no matter the weather.

Loft conversions

If you have space in your attic, turning it into a room is a smart idea. It’s great for an extra bedroom or a quiet office space. The good thing about loft conversions is that you don’t need to build outward, but you’ll need to make sure it’s safe to use as a living space.

Basement conversions

Your basement or attic can also be turned into a new room. It could be a playroom, a home cinema, or anything else you need. The main thing to think about here is keeping it dry and well-lit, since basements can be damp and dark.

Each of these options has its own benefits and things to think about. The best choice depends on what you need, your budget, and the layout of your current house.

What Are the Design Considerations and How to Plan for an Extension?

When you’re thinking about making your house bigger, the design is really important. You want the new part of your house to look and feel like it belongs with the rest of your house. Think about how the new space will be used and how it connects to your current rooms. For example, if you’re adding a new kitchen, it should be easy to walk to from the living room or dining area.

Natural light is another big thing to think about. Big windows or skylights can make your new space feel brighter and more welcoming. Also, think about how the extension will look from the outside. It should match your house’s style and colours.

Lastly, don’t forget about the practical stuff, like where the water and electricity will come from for the new part of your house. You might need to update your heating system too, to make sure the new area is warm and cosy.

How to Budget and Manage the Cost?

Talking about money is really important when you’re planning to make your house bigger. In Ireland, the cost can vary a lot depending on what you’re doing. For a basic extension, you might spend around €1,500 to €2,000 per square metre. But if you’re going for something high-end, it could be more than €2,500 per square metre.

Remember, there are other costs too, not just building. You might need to pay for things like planning permission, which can be a few hundred euros. And if you need to stay somewhere else while the work is being done, that’s an extra cost.

It’s always a good idea to plan for extra costs, just in case. Sometimes, things don’t go as planned, and you might end up spending more than you thought. A good rule is to add an extra 10–20% to your budget for these unexpected things.

By keeping a close eye on your spending and planning carefully, you can make sure your house extension doesn’t cost more than you can handle.

How to Check Legalities and Permissions?

Before you start building, it’s important to know about the rules. In Ireland, sometimes you need permission from the local council, especially if you’re making your house a lot bigger or changing how it looks from the street. It’s a good idea to talk to your local planning office early on. They can tell you what you can and can’t do. 

If you need permission, you’ll have to fill out some forms and maybe give them a plan for your extension. This can take a bit of time, so it’s good to start early.

How to Choose the Right Contractors for Building an Extension?

Finding the right people to build your extension is really important. You want someone who does a good job and is fair with their prices. Start by asking friends or family if they know anyone good. You can also look online for builders with good reviews. Once you find a few, talk to them and ask for quotes. 

Don’t just go for the cheapest one; make sure they have experience and seem trustworthy. It’s also a good idea to look at some of their past work if you can.

How to Manage the Project?

Keeping an eye on the building work is key. Even if you have good builders, it’s good to check on the progress yourself. Make sure they’re doing what you agreed on and staying on schedule. If there are any problems, it’s better to talk about them right away. 

Also, keep track of your spending as the project goes on. This way, you won’t have any surprises with money at the end.

How to do Interior Design and Finishing?

Interior Design
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Once the building part is done, it’s time to make the new space feel like home. Think about the colours and furniture. You want them to match the rest of your house, so everything flows together. If your extension is for a specific purpose, like a home office or playroom, think about what you need in there.

For example, a home office might need a good desk and lots of light, while a playroom might need easy-to-clean floors and lots of storage for toys. The little details, like curtains, cushions, and pictures, can really make the space feel special and finished.


Extending your 4-room house can transform your living space to meet your evolving needs. From planning designs to managing budgets, understanding legalities, choosing the right contractors, and adding those final interior touches, each step brings you closer to the home of your dreams.

If you’re considering an extension and need expert guidance, Coastal Homes is here to help. Our team specialises in creating stunning, smooth extensions that would perfectly fit your lifestyle. Contact us today to start your home transformation with Coastal Homes.


What are the first steps in planning a house extension?

Start by defining your needs for the extension, then consult with an architect or builder. Check the local planning regulations and budget for your project.

Do I need planning permission for a house extension?

Planning permission depends on the size and type of extension and local regulations. Generally, small or internal changes might not need permission, but it’s always best to check with your local council.

How long does it take to complete a house extension?

The duration varies based on the extension type and size. A small single-storey extension might take 10–12 weeks, while larger or two-storey projects can take several months.

How much does a typical house extension cost?

Costs vary widely depending on size, materials, and location. As a rough estimate, prices can start from around €1,500 to €2,000 per square metre in Ireland.

Can I live in my house during the extension work?

Yes, in many cases, you can, especially for smaller extensions. However, for larger projects, it might be more practical to find temporary accommodation.

Will a house extension add value to my property?

Generally, yes. Well-designed and executed extensions can significantly increase your property’s market value, especially if you add functional living space.

Building your dream home?

Trust Coastal Homes to make it a reality! Our experienced team of professionals is dedicated to providing top-quality construction services that meet your unique needs. Contact us today to learn more about our services.