Insulation FAQs

Insulation can do wonders for any build, so it’s essential that you understand what’s required.

To shed some light on insulation, we’ve put together this handy guide full of topics and tips for your next job.

Here at Fastbuild, we provide a range of insulation and other trade building supplies at great prices. Take a look at our offers today!

What Does the R-Value Mean for Insulation?

The R number measures how well insulation resists the flow of heat. The higher the R number (e.g. R-3.5), the better the insulation is at keeping the heat on one side (e.g. indoors) without letting it escape.

There are a range of other measures for insulation performance on the market, but they all do slightly different things. Two of the other most common include:

Thermal conductivity - how easily heat flows through a material independent of its thickness. The higher the number (in W/mK), the lower the insulation’s performance.
U-Value - Takes into account more potential methods of heat loss than the R-Value and is measured in W/m2K.

What R-Value is Required for UK Insulation?

There are various regulations around insulation in buildings, but there is no set requirement for R-Values.

The R-Value of insulating materials is derived with the thickness taken into account. Therefore, you can improve the R-Value of an insulator by increasing its thickness.

The R-Value can be used to measure the general performance of an insulator. To understand building requirements, speak to your architect or structural engineer, or consider looking into the recommended U-Value.

What are the Different Types of Insulation?

There are various types of insulation available, each ideally suited to a specific area or purpose.

Insulation Board - Cost-effective and easy to handle, perfect for large walls.
Insulation Slab - Usually used on lofts or floors, designed to fit between studs and joists.
Roll or Batt Insulation - Similar to slabs, designed for easy installation in walls or floors.
Multifoil Insulation - A thin, foil-based insulation that’s perfect for small spaces or upgrading existing insulation.
Acoustic Insulation - Delivers soundproofing alongside insulation, a great choice for internal stud walls.

Each of the types mentioned above can be divided further based on the various materials available, meaning there are plenty of options for every need or budget.

Is Loose-Fill Insulation Good?

Loose-fill insulation is an excellent choice for hard to reach spaces and where existing insulation needs additional support.

Many popular insulation materials, such as fibreglass and rock wool, are also available as loose-fill.

What is the Best Insulation for Stud Walls?

Unlike with external walls, one of the biggest things to consider when insulating stud walls is soundproofing.

It’s often recommended to use acoustic insulation to ensure stud walls meet soundproofing requirements. These can help stop sound from passing through while also providing thermal qualities.

What is the Best Type of Insulation for an Attic?

Generally, an insulation roll is recommended for attics and lofts, as it’s easy to install and can be used for insulating the rafters if required.

Many of the most popular types of insulation can be used here, including mineral wool and fibre wool. Slabs and boards can be used to fit between joists and rafters, while foil insulation can be an alternative for attics.

Is Sound Proof Insulation Worth It?

There are some minimum requirements for soundproofing for walls, so these should always be considered. There are also many different ways to solve sound issues, including acoustic plasterboard.

Soundproof insulation is a good choice in areas where more soundproofing is required. However, as its density is increased, the thermal value of the insulation is slightly decreased.

Generally, soundproof insulation is a great choice for internal stud walls where its thermal demands will not be as high.

How Long Does Insulation Last?

The lifespan of your insulation depends on both the quality of the material and the quality of the application.

Generally, all insulation should be good for the first 15 years. Beyond that, it may need replacing if there’s a notable drop in quality. Otherwise, most insulation should be okay for a few decades so long as it’s not under too much strain.

Modern fibreglass insulation, when properly installed, can last up to 100 years.

Do I Need to Remove Old Insulation Before Installing New?

The answer to this question depends on two points:

Where the insulation is located
The state of existing insulation

For roofs or attics, it’s generally recommended to put new insulation on top of existing older insulation, as it can provide additional thermal support.

For wall insulation, removing the old material may be necessary due to issues with space.

Regardless of location, if the existing insulation has damp, it’s recommended that it’s removed to avoid causing problems for the new insulation.

We hope this list will help you with your next insulation job! For more helpful guides and info, be sure to explore our blog and follow us on our social media channels.