Building thermal insulation · Glass wool
SCG STAY COOL
- Thickness
- 75–150 mm
- Thermal resistance (R)
- 1.79 m²·K/W (75 mm)
Where do you start when choosing insulation?
In short
Start from the problem you need to solve, not from a material name. Once you know the problem, you know the function the insulation must perform: keeping heat out, blocking sound, absorbing sound, preventing condensation drips, fire protection or high-temperature service. Then look at location and operating conditions, choose the material, and finally the product whose manufacturer documents say it suits that job.
Why not start from the material?
Glass wool, stone wool, elastomeric rubber and PE foam are all "insulation", but each does different jobs well. The same material can suit one job and not another. Choosing the material first often gives the wrong fix — for example, fixing sound-absorbing panels on a wall to stop noise from next door, which does not reduce the sound passing through the wall (see Soundproofing vs sound absorption).
Steps 1–2: problem → function
| Problem | Function needed | Product category | Read next |
|---|---|---|---|
| --- | --- | --- | --- |
| Hot house, hot roof, air-con slow to cool | Thermal insulation | Building thermal insulation | Hot house |
| Hearing noise from next door | Sound insulation (as part of a wall/ceiling system) | Sound insulation | Neighbour noise |
| Echoey room, speech hard to follow | Sound absorption | Sound absorption | Room echo |
| Noise from machines, pumps or compressors | Sound insulation and absorption together | Sound insulation | Machine noise |
| AC pipes or ducts dripping water | Condensation control | Pipe insulation · Duct insulation | Why AC pipes drip |
| Fire protection required by the design | Fire protection (as part of a tested system) | Fire protection | Fire performance terms |
| Steam pipes, furnaces or hot equipment | High-temperature insulation | Industrial insulation | Service temperature |
One job may need more than one function — for example a partition that must block sound and also meet the building's fire requirements. Rank which function matters most, then check that the chosen product also covers the others.
Step 3: location and operating conditions
The same function in a different place may need a different product. Check:
- Where it goes — under the roof, on the ceiling, in a wall cavity, under a floor, around a pipe or duct, or on equipment
- Temperature of the surface — cold (chilled-water pipes, cold ducts) or hot (steam pipes, furnaces); it must be within the material's service temperature
- Surrounding humidity — damp areas and cold surfaces in humid air call for thinking about condensation and a vapour barrier
- Indoors or outdoors — sun, rain and knocks affect the facing or jacket needed
- Available space — the thickness you can actually fit limits the thermal resistance or acoustic result you can get
- Project requirements — fire requirements, cleanliness or documents the designer needs
Step 4: material by function
Once function and location are known, the material options narrow down. Typical uses:
- Glass wool and stone wool (fibrous) — used for both thermal and acoustic work; some stone wool products are used at high temperatures or in fire-protection systems, depending on the product. See Stone wool vs glass wool
- Elastomeric rubber (closed cell) — commonly used on AC and chilled-water pipes. See Closed-cell vs fibrous
- PE foam and reflective foil — under roofs and on ceilings; foil works well when there is an air space in front of it. See Reflective foil
- Ceramic fibre — industrial work at very high temperatures
- Open-cell acoustic foam and absorbing panels — reducing reflected sound and lining the inside of ducts
Step 5: pick the product from its documents
- Check that the manufacturer's documents list your application
- Compare the value that matches the function: for heat, λ and R-value at the thickness you will use; for absorption, NRC; for sound insulation, the STC / Rw of the whole wall system the manufacturer tested
- Check the test conditions, such as measurement temperature, thickness and standard
- Prepare the details listed in Questions to ask before buying insulation
Common mistakes
- Choosing by material name or price per roll before knowing the problem
- Using sound-absorbing panels to fix noise from the next room
- Looking at one number, such as density, and treating it as a performance indicator
- Forgetting accessories such as foil tape, adhesive or pins, found under Accessories
- Leaving areas uncovered — see Gaps and compression
If you are not sure what causes the problem — for example whether a room is hot because of the roof or a sun-facing wall — start from the problem pages, or send us the site details to review before choosing a product.
Sources
- Building Science Corporation — Info-501: Installation of Cavity Insulation
- National Research Council Canada (IRC) — Control of Sound Transmission through Gypsum Board Walls
- ROCKWOOL — Safe 'n' Silent Pro data sheet
- Microfiber Industries — MicroRoof brochure (EX-BR-001, 2023)
- ASTM C518 — Standard Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus
Related products
Categories and example products for this topic
Building thermal insulationSound insulationSound absorptionDuct and HVAC insulationPipe insulationIndustrial and high-temperature insulationFire protectionInstallation accessories
- SCG STAY COOL — Heat in a house: foil-wrapped glass wool laid on the ceiling, no need to open the roof
- ROCKWOOL Safe 'n' Silent Pro — Sound insulation: stone wool slab for wall and ceiling cavities, part of a wall system
- SCG Cylence Zoftone — Echo control: ready-made glass-cloth-wrapped glass wool panel for mounting on walls
- AEROFLEX Tube Insulation — Cold pipes: closed-cell EPDM tube for chilled-water and refrigerant lines
Sound insulation · Stone wool
ROCKWOOL Safe 'n' Silent Pro
- Thickness
- 25–100 mm
- Density
- 40–100 kg/m³
- Sound absorption (NRC)
- 0.90–1.00
Sound absorption · Glass wool
SCG Cylence Zoftone
- Thickness
- 25–50 mm
- Density
- 32–64 kg/m³
- Sound absorption (NRC)
- up to 1.00
Pipe insulation · Elastomeric foam
AEROFLEX Tube Insulation
- Tube bore
- 6–165 mm
- Wall thickness
- 6–50 mm
- Service temp.
- -57 – 125 °C