Do you have a dormer bedroom that is too cold in the winter and too hot in the summer? It's a common issue, especially in many dormer bungalows across Ireland, where poor insulation leads to discomfort and high energy bills. 

This blog post is your go-to guide for insulating a dormer bedroom, using the best materials and techniques for your situation. Follow our step-by-step advice, and you'll transform your space into a cosy retreat, perfect for all seasons. 

Ready to take the first step towards a more comfortable home? Let's dive into how you can achieve a well-insulated dormer bedroom, promising you warmth and efficiency all year-round.

Why Insulate a Dormer Bedroom?

Insulating a dormer bedroom is not only a matter of comfort but also a matter of energy efficiency and environmental responsibility. Here are some of the benefits of insulating a dormer bedroom:

Reduce heat loss and gain

Insulating a dormer bedroom can help prevent heat from escaping through the roof and walls in the winter and from entering through the roof and walls in the summer. This can help maintain a consistent and optimal temperature in your dormer bedroom throughout the year, regardless of the weather outside.

Save money on energy bills

By reducing heat loss and gain, insulation can lower your energy consumption and costs. The Sustainable Energy Authority of Ireland (SEAI) suggests that attic insulation could save up to €200 per year on heating bills. A similar effect can be expected by insulating your dormer bedroom.

Improve indoor air quality and health

Insulation can improve indoor air quality by preventing moisture condensation, which can lead to mould growth and dampness. This is particularly beneficial for children and the elderly, who may be more susceptible to respiratory problems, allergies, and asthma. Additionally, insulation can reduce noise pollution, creating a quieter environment.

Increase property value and appeal

A well-insulated dormer bedroom can increase your property’s value and appeal, especially if you plan to sell or rent it. According to an SEAI study, homes with a higher Building Energy Rating (BER) can sell for up to 10% more. Insulating your dormer bedroom can improve your home’s BER, making it more attractive on the market.

How to Insulate a Dormer Bedroom?

Insulating your dormer bedroom is a relatively simple process. Here are the steps involved:

Step 1: Measure the Area

The first step in insulating your dormer bedroom is to measure the area that needs to be insulated. Measure the length and width of the walls and roof of your dormer bedroom to determine the total area that needs to be insulated.

Step 2: Choose the Type of Insulation

The next step is to choose the type of insulation that you want to use. Consider the R-value of the insulation, which is a measure of its thermal resistance. The higher the R-value, the better the insulation.

Step 3: Prepare the Area

Before you start insulating, you need to prepare the area. Remove any old insulation or debris from the walls and roof of your dormer bedroom. Clean the area thoroughly to ensure that there is no dust or dirt.

Step 4: Install the Insulation

Once the area is prepared, you can start installing the insulation. Follow the manufacturer’s instructions carefully to ensure that the insulation is installed correctly. Make sure that there are no gaps or spaces between the insulation and the walls or roof of your dormer bedroom.

Step 5: Seal the Gaps

After the insulation is installed, you need to seal the gaps and spaces between the insulation and the walls or roof of your dormer bedroom. Use a sealant to fill any gaps or spaces to prevent air leakage.

How to Insulate a Dormer Bedroom Roof?

The roof plays a vital role in maintaining the temperature balance within a dormer bedroom, accounting for up to 25% of heat loss. There are two main ways to insulate the roof of a dormer bedroom: from the inside or from the outside.

Inside Insulation Method

This method involves placing insulation between the rafters, ensuring a minimum thickness of 150mm. It’s crucial to maintain a 50-mm air gap between the roof tiles to prevent condensation. This setup should be sealed with a vapour barrier and finished with plasterboard.

Outside Insulation Method

This approach requires removing the roof tiles to apply insulation directly to the rafters. Opt for materials like rigid boards or spray foam with at least 100 mm of thickness. Finish with a breathable membrane and reinstall new roof tiles for a weatherproof exterior.

Insulating the Ceiling of a Dormer Bedroom

Insulating the ceiling can prevent up to 10% of your home’s heat loss, making it another key area of focus. Here are some methods and materials that you can use to insulate your dormer bedroom’s ceiling:

From the Inside

Place insulation between the ceiling joists, ensuring a 100-mm thickness for optimal thermal performance. An air gap of at least 25 mm above the insulation is necessary to avoid condensation issues, covered with a vapour barrier and plasterboard for a polished appearance.

From the Outside

Removing roof tiles to add insulation on top of the ceiling joists forms a ‘warm roof’ system, eliminating the need for an internal air gap and vapour barrier. Materials used could be rigid boards or spray foam, covered with a breathable membrane and then finished with new roofing tiles.

Insulating Dormer Walls

The walls of the dormer bedroom can also lose up to 35% of heat through conduction and convection, especially if they are not insulated or have gaps and cracks. To insulate the walls, you have three main options:

From the Inside

This method involves installing insulation on the inner surface of the walls, creating a warm wall system. This method can be done by either fixing rigid boards to the walls or by building a stud wall (a wooden frame) and filling it with flexible rolls. 

The insulation should be at least 50 mm thick to achieve a good level of thermal performance. The insulation should also be covered with a vapour barrier and a plasterboard to create a smooth and finished surface.

From the Outside

This method involves installing insulation on the outer surface of the walls, creating a cold wall system. This method can be done by either fixing rigid boards to the walls or by applying spray foam to the walls. 

The insulation should be at least 50 mm thick to achieve a good level of thermal performance. The insulation should also be covered with a breathable membrane and a cladding (a decorative layer) to create a durable and weatherproof surface.

From the Cavity

This method involves injecting insulation into the cavity (the space between the inner and outer walls), creating a filled wall system. This method can only be done if your walls have a cavity, which is common in houses built after the 1920s. 

The insulation can be either beads, granules, or foam, and it should fill the entire cavity to achieve a good level of thermal performance. The insulation should also be installed by a certified installer to ensure quality and safety.

How to Insulate the Windows of a Dormer Bedroom?

The windows of the dormer bedroom can lose up to 20% of heat through conduction, convection, and radiation, especially if they are single-glazed or have gaps and draughts. To insulate the windows, you have two main options:

By Replacing Them

This method involves installing new windows that have a higher energy rating and better thermal performance. The energy rating of windows is measured by the Window Energy Rating (WER) scheme, which ranges from A++ (the most efficient) to E (the least efficient). 

The thermal performance of windows is measured by the U-value, which indicates how much heat passes through the window. The lower the U-value, the better the insulation. The recommended U-value for windows in Ireland is 1.6 W/m2K or lower. 

Replacing your windows can be a costly and disruptive process, but it can also have a significant impact on your energy efficiency and comfort.

By Improving Them

This method involves adding insulation to your existing windows, without replacing them. This can be done by either installing secondary glazing (a second layer of glass or plastic) or applying window film (a thin layer of material) to your windows. 

Secondary glazing can reduce the U-value of your windows by up to 63%, while window film can reduce it by up to 33%. Improving your windows can be a cheaper and easier process than replacing them, but it can also have a lower impact on your energy efficiency and comfort.

Conclusion

Insulating a dormer bedroom is a worthwhile investment that can improve your comfort, energy efficiency, and property value. However, it is also a complex and challenging project that requires careful planning, professional advice, and quality installation. 

There are different types and methods of insulation for different surfaces and structures of your dormer bedroom, and each one has its own advantages, disadvantages, costs, and times. Therefore, it is important to do your research, compare your options, and choose the best solution for your specific dormer bedroom.

If you need professional help with insulating your dormer bedroom, you can contact BuildPro, a building contractor company in Ireland. We have the experience and expertise to handle any type of insulation project, from roof to floor. Contact us today for your dormer bedroom insulation needs.