Insulation and heat reduction — price, types and what to check
XPS, PUF, glass wool, rock wool and reflective barriers.
Top floors under a bare RCC roof run much hotter than lower floors. Roof and wall insulation cuts heat gain and AC bills, and is easiest to add during construction.
The basics
- Common materials: XPS and EPS boards, PUF, glass wool and rock wool.
- Roofs gain the most heat; insulate over the slab, under screed or tiles.
- Sound insulation uses dense mineral wool inside double drywall.
Insulation and heat reduction types and price ranges in India
| Type | Specification | Best used for | Indicative price |
|---|---|---|---|
| XPS board | 25–50 mm | Roof insulation under screed | ₹45–110 |
| EPS board | Expanded polystyrene | Budget roofs and walls | ₹20–50 |
| PUF spray / panel | Polyurethane | Roofs and sheds | ₹60–150 |
| Glass wool | 25–75 mm | Ceilings, drywall, acoustics | ₹15–45 |
| Rock wool | 50 mm, dense | Fire and sound insulation | ₹30–70 |
| Reflective foil barrier | Radiant barrier | Under sheet roofs | ₹12–30 |
| Brickbat coba / terracotta tile | Traditional | Terrace insulation and slope | ₹35–70 |
Quality checks before you accept delivery
- XPS should be firm enough for foot traffic — ask for compressive strength.
- Glass wool must sit in a closed ceiling or be encapsulated.
- Compare thermal conductivity (k-value): lower is better.
- Measure board thickness and check density claims on the pack.
- Joints should be staggered and tight.
- Insulation should be continuous at edges and around pipes.
Pro tips
- Lay XPS over the waterproofing, then screed and tiles (an inverted roof).
- A light-coloured reflective finish plus insulation beats either alone.
- Insulate or use AAC on west walls to cut afternoon heat.
- Tape board joints before laying screed.
- Keep boards covered from sun and wind during installation.
Mistakes to avoid
- Placing insulation under the waterproofing where it gets soaked.
- Exposed glass wool shedding fibres into rooms.
- Relying on paint alone to cool a flat RCC roof.
- Compressing wool insulation — it loses much of its value.
- Leaving gaps around roof penetrations.
Where you can save
- Roof insulation during construction pays back through lower AC bills.
- AAC block walls already insulate better than clay brick.
How much you need
Insulate the full terrace area plus the inside of parapets.
Brands to know
Owens Corning, Twiga, Rockwool, Supreme, Lloyd Insulations
Related materials
Waterproofing and chemicalsSmall cost, big protection against leaks and cracks.False ceiling and POPGypsum, POP, PVC and grid ceilings.Paints and puttyPutty, primer, emulsion — and the final colours.Ready-mix plaster and gypsumCement, ready-mix and gypsum plaster, mesh and bonding agents.Wall panels and wallpaperFluted panels, WPC louvers, PVC boards, wallpaper, acoustics.