Rockwool Vs. Fiberglass For Soundproofing

Some people can’t stand noise, thus, to make their surroundings peaceful, they search the market for the greatest soundproofing materials. While searching for soundproofing materials, it is very much expected that you will come across rock wool and fiberglass. But which one to choose might be a question that will strike your head.

While fiberglass can be a good option if you are on a tight budget, rock wool outperforms it in all aspects.

In this article let’s compare rock wool and fiberglass, the two sound-deadening materials to understand what’s similar between them, what is different, and how effective each one can be.

Let’s find out which one is a better choice when it comes to soundproofing.

Rockwool vs Fiberglass

Before comparing both of them we need to understand what is rockwool and what is fiberglass.

What is Rockwool?

Rock wool is also known as mineral wool due to its fibrous texture. Being made from natural and recyclable resources, it is a more environment friendly solution than fiberglass.

Basalt is a volcanic rock that is heated to a blistering 3,000 degrees Fahrenheit until it liquefies. Slag, a by-product of steel that typically ends up in landfills, is then combined with basalt to create Rockwool. After that, the mixture is spun into threads and flattened with a hydraulic press. To buy rock wool at an affordable price, visit Amazon.

Price: A pack of 25 mini-blocks (2″ each) would cost around $15-$20.


  • Extremely dense
  • Amazing soundproofing
  • More robust
  • Simple to set up
  • Water-resistant
  • Fire-resistant


  • More expensive
  • Greater pH level
  • Not biodegradable
  • Potential health risks include eye and skin irritation as well as breathing difficulties for some people

What is Fiberglass?

In the 1930s, a mistake led to the development of fiberglass insulation. Thin, fiber-like glass threads were produced when glass blocks were vacuum sealed using a high-pressure jet system.

Glass is heated to extremely high temperatures and then compressed to form large rolls or blankets in order to make the fiber-like threads of glass. This insulation is less environmentally friendly than Rockwool because it is made from glass by manufacturers. It is, however, biodegradable.


Price: A Pack of 6 rolls (3.5 in x 15 in x 62.7 ft each) would cost around $250

fiberglass roll
source: insulation4us


  • Good sound insulator
  • Holds up against extreme weather conditions
  • Cost-effective
  • Durable
  • Fire-resistant
  • Easy to install
  • Low maintenance


  • Not water-resistant
  • Dangerous for those with asthma because fiberglass particles can get stuck in the lungs and trigger uncontrollable sneezing and coughing
  • Depending on where you place it, covering could be necessary to limit exposure to fiberglass particles.
  • Lacks breathability

Rockwool vs Fiberglass

I conducted a survey and asked people which one of these is better for soundproofing. Here’s what people who have used both of them think about it:

U Moe Sweet“Rockwool for isolation, glasswool for absorbtion.”
Pipmeister Says“Depends what kinda music/style you are making. If you are more like Guns and Roses or Metallica, I’d go with Rockwool. If you are more like Folk/new Age, I’d stick with Fibreglass.”
Joe Bloggs“Fibreglass batts for absorbers that stand vertically or hang overhead. They are more rigid in structure and do not sag over time. I always combine them with a very porous polyester fabric , and a layer of dacron which keeps the micro fibres at bay. Rockwool for large cavities and bass traps.”
Kobboon Hansen“They both have their sound absorption co efficient at different density. However at same density i would go with glass wool which s cheaper where i am”
Paul Bishop“Fiberglass for deep traps, rockwool for shallow traps.”
Dan Shephard“Rockwool or glasswool are better fiber material it when you keep it I tact say for example if you where to get a deepish picture frame say 20cm deep approx and line it with intact pillows or like duvets cutouts and line with some sort of bedsheets that’s a perfectly acceptable audio panel.

Cuddly stuffed toy are also really good for absorbtion and look cool as he’ll as well if you like getting creative.”
David Florio“Better is what is best for a particular application. Not necessarily ALL applications.”

Comparative Factors

There are more similarities than differences between Rock wool and Fiberglass. We will use the factors listed below to contrast and compare the two materials.

Ease of Installation

Rockwool and fiberglass are both easy to install. Your preference is all that matters. Watch the following videos to learn how to install rock wool and how to install fiberglass.

source: youtube

Rockwool and fiberglass are both available in batts, rolls, and blankets, which you can then trim to your requirements. Rockwool and fiberglass can also be blown, which is ideal for confined spaces and tight corners. As opposed to purchasing a full blanket, you can spray in the insulation.

Soundproofing Quality

Sound will be more effectively muffled by insulation with a higher density. If soundproofing is one of your main priorities, Rockwool is normally the best option because it is thicker than fiberglass.

To get the best results, go for high-performance Rockwool, which is sound-absorbing and has a density that is twice that of conventional Rockwool. Although fiberglass insulation will provide some sound absorption, it won’t likely compare to Rockwool.


Fiberglass is more cost-effective if the price is a major consideration in your choice. In contrast to Rockwool, which typically costs $0.62 per square foot, fiberglass is typically $0.50 per square foot. In the long term, Rockwool might be a wiser investment if you’re seeking ways to lower your home’s utility costs since fiberglass might require reinstallation owing to its lack of water resistance.


When choosing insulation, it’s important to consider the R-value, which measures heat resistance. The insulating blocks absorb less heat as the R-value decreases.

A normal R-value for Rockwool is between 3 and 3 1/3 per inch, whereas a typical R-value for fiberglass is between 2 1/5 and 2 7/10 per inch

When choosing R-values, a greater R-value is crucial if you want to reduce your utility costs by better controlling the flow of heat in your home. R-values for floor insulation can be as low as R10 and as high as R60 for attics.

Below video would help you in choosing the best insulation for your home project.

source: youtube

Fire Safety

Rockwool and fiberglass both have low ignition temperatures, making them non-flammable substances. However, when subjected to intense heat or flames, these materials have the ability to emit toxic fumes, posing a health risk in the event of a fire.

Since Rockwool burns more slowly and creates less smoke than fiberglass, it is typically thought to be more fireproof.


In order to avoid rotting and eventual bacterial growth, insulation must be water-resistant.

Sadly, unlike Rockwool, fiberglass is not water-resistant. Fiberglass insulation will eventually develop serious problems and lose its ability to insulate your home as a result of absorbing water and becoming soggy.

Durability and Strength

In comparison to other insulation materials, Rockwool is more resistant to sagging and crumbling over time. It is a fantastic option for moist situations because it is also mold and mildew-resistant.

Incorrect installation can cause fiberglass to droop or disintegrate over time, making it less durable than Rockwool. Additionally, when exposed to dampness for extended periods of time, the material is susceptible to deterioration.

Weight and Fitting

Rock wool is a heavy substance that weighs three times as much as fiberglass.

Rockwool weighs somewhere between 20 and 45 lb/sq foot. Additionally, it comes in enormous panels, making it challenging for people without much DIY experience to install it themselves.

Fiberglass is a thin material with a density of 2-4 pounds per square foot. Additionally, it comes in compact rolls, which makes it simple for homeowners to install on their own.

Also Check:

Find the Best Soundproof Insulation

Sustainability and Environment Impact

Although recycled elements, such as scrap steel make up the majority of Rockwool’s composition, it is not biodegradable like fiberglass, therefore you cannot consider it to be more environmentally friendly.

The bad thing about Rockwool is that it can stay in landfills for years, but the good news is that you can utilize it in various applications, like hydroponics. This is a common technique for growing plants without soil. Due to its spongy texture and thermal stability, Rockwool is an excellent material for plants after being well cleaned.

While fiberglass is not harmful to the environment, it can cause skin and eye irritation as well as breathing problems. As a result, it’s crucial to take precautions whenever working with fiberglass insulation, such as using gloves, a long sleeve shirt, a mask, and a pair of goggles, and working in a well-ventilated location.

To Wrap Up

Both fiberglass and rock wool are natural products with insulating qualities. You should be able to determine which soundproofing material is better after reading about the similarities and differences between the two.

However, “better” is a relative phrase, so when comparing rock wool with fiberglass, you should take factors like price and use into consideration.

In the end, though, rock wool is the better soundproofing material, despite the higher cost. If the cost of rock wool is within your budget, it is best to consider rock wool over fiberglass.


  1. How to install Rock wool?

Using a utility knife or saw, cut the rock wool to the appropriate size, then fit it into the desired location in your home.

  1. How long can fiberglass last?

Rockwool insulation lasts longer than fiberglass insulation, which has a lifespan of 20 to 30 years. When the material’s life cycle is complete, you can recycle it.

  1. Which material is rodent-proof?

None of the materials are rodent-proof. However, it is seen that rodents find it more difficult to chew through rock wool than fiberglass.