What is the Best Cavity Wall Insulation for a New Build in 2024?

In 2024, selecting the most efficient cavity wall insulation for new builds is important for energy efficiency and comfort. Insulation technology advances deliver many choices, each with unique benefits for specific project needs. This guide investigates the top cavity wall insulation options available this year, stressing their advantages, disadvantages, and regulations to help make informed decisions for any new-build project.

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Rigid insulation boards are the top choice for cavity wall insulation in new builds in the UK, thanks to their exceptional thermal performance and moisture resistance. Foam insulation follows closely behind, offering superior gap-filling capabilities and high thermal efficiency.

When constructing a new home, it's recommended to consider using rigid insulation boards like PIR (polyisocyanurate) and phenolic boards. These boards offer superior thermal performance, durability, and moisture resistance. 

They have high R-values, which means they provide excellent thermal insulation with thinner layers compared to other materials, helping to achieve the required U-values for new builds. Their high moisture resistance also helps prevent cavity wall insulation causing damp cavity, which is critical for maintaining the building's integrity in the UK's climate. Additionally, these boards are durable, ensuring long-lasting insulation performance, making them an ideal choice for modern construction.

Rigid insulation boards are known for their superior insulating properties but often have a higher price tag than other insulation options. Additionally, their installation usually requires a broader cavity, which might challenge specific design requirements.

Foam insulation is highly recommended for newly built homes due to its exceptional thermal performance and ability to fill gaps effectively. It provides excellent thermal resistance, helping to achieve high R-values and superior energy efficiency by minimising heat loss through walls. Its expanding nature allows it to fill gaps and voids, creating a continuous thermal barrier that reduces air leakage and improves insulation effectiveness. Despite these benefits, foam insulation can be more expensive than traditional materials like mineral wool or fibreglass. 

However, it's important to note that foam insulation can result in excessive airtightness, which poses potential risks. A highly airtight home necessitates not just any ventilation system, but a well-functioning one, to maintain indoor air quality. Inadequate ventilation can result in overheating and carbon monoxide buildup.

Regarding selecting the best cavity wall insulation for your newly built home, evaluating factors like thermal performance, cost-effectiveness, moisture resistance, and compliance with building regulations is important. Additionally, it is necessary to consider characteristics such as the local climate, cavity size, and installation requirements. 

Rigid insulation boards like PIR and phenolic boards deliver excellent thermal performance and are particularly suitable for projects with limited space. Spray foam cavity wall insulation expands to fill gaps, creating a continuous thermal barrier that significantly reduces heat loss. Additionally, mineral wool offers good thermal insulation, fire resistance, and acoustic properties. Polystyrene beads are effective for cavity wall insulation and are easy to install. Carefully evaluating these materials can help you select the one that best meets your new build's thermal performance needs.

When planning for the cost of insulation materials for a new build, it's important to understand that prices can vary depending on the type of insulation. While some materials, like spray foam, tend to be more expensive, others, such as mineral wool and polystyrene beads, are more budget-friendly. 

Below is a table showing different insulation materials suitable for newly constructed homes:

The size of the cavity wall gap must be assessed when selecting insulation materials. Some materials are better suited for smaller cavities, while others perform better in bigger gaps. 

Selecting the suitable material for cavity size guarantees optimal insulation performance and energy efficiency for newly built homes.

Insulation materials can be more or less sustainable. Some materials are sustainable and recyclable, while others, like spray foam, are not.

Here are some sustainable insulation material options on the market:

Alternatively, there are some high performing, but less sustainable insulation materials on the market:

New construction must include cavity wall insulation to meet current building regulations. The primary factor to consider is the age of your home. Homes constructed between the 1920s and 1980s generally have cavity walls. Since the 1980s, new building regulations have made it compulsory for newly built houses to incorporate insulation material within cavity walls.

The outer walls of any cavity wall must have a thickness greater than 260mm.

An excellent way to determine the appropriate level of insulation for cavity walls is to refer to your country's building specifications. These specifications are outlined in guidance documents detailing how to meet the energy efficiency standards in the Building Regulations:

Evaluating the thermal performance of a new building is important, with the u-value being a key factor. A lower u-value indicates better insulation and less heat loss. If high-quality insulation is a priority, several materials are worth considering.

Getting multiple quotes is your best bet at landing a bargain on your cavity wall insulation job. By properly researching and vetting your installer options, you increase your chances of finding a professional that is within your budget.

However, finding a professional that is also affordable can be a daunting task. Most prospective customers find themselves stuck in an endless loop of websites and phone calls, but luckily GreenMAtch UK can help free you from this burden.

Forget about countless online searches and scheduling appointments; complete our brief online form in 30 seconds. You'll get up to 3 free quotes from reliable installers near you. Multiple quotes can save you money, help you compare prices and different materials, and find the best installers for your project. Take the first step now by clicking the button below!