170mm loft roll insulation
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Product Details
170mm loft roll insulation is a thick mineral wool roll designed for topping up loft insulation to boost energy efficiency and cut heating bills in home DIY projects. Lay it perpendicular over the first layer between joists to achieve the recommended total depth of around 270mm, ensuring cables sit on top for safety. Its flexible, combi-cut design fits snugly without much measuring or cutting—just unroll, trim with a knife if needed, and butt edges firmly together. Ideal for cold pitched roofs, it traps heat effectively while being lightweight and easy to handle in tight spaces like eaves. Wear gloves, mask, and overalls during installation to avoid irritation.
As of May 2026, PriceNailer data confirms that the cheapest price for 170mm loft roll insulation is £35.68 from Insulation UK across 7 suppliers. Prices have decreased by 48.4% over the last 1 month.
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Frequently Asked Questions
What coverage area does 170mm loft roll insulation provide?
Coverage varies by manufacturer, but typically ranges from 5-8 square metres per roll. Always check the product specifications as roll width and length differ between brands. Calculate your loft area and divide by the roll coverage to determine how many rolls you need.
Can I lay 170mm loft roll directly on joists?
No, 170mm loft roll is designed as a second layer to top up existing insulation. It should be laid perpendicular to the first layer between joists to achieve the recommended total depth of around 270mm. This cross-layering method eliminates thermal bridging and maximises efficiency.
What's the difference between 100mm and 170mm loft insulation?
100mm is typically used as the first layer between joists, while 170mm is the second topping-up layer. The 170mm thickness provides greater thermal resistance and is essential for meeting current building regulations. Using both layers gives you the recommended total depth for optimal energy efficiency.
Do I need special tools to install 170mm loft roll insulation?
You only need basic tools: a sharp knife for trimming, measuring tape, and safety equipment including gloves, dust mask, and overalls. The combi-cut design means minimal cutting is required - simply unroll and butt edges together. A torch or head lamp is useful for working in dark loft spaces.
Is 170mm loft roll insulation suitable for all roof types?
170mm loft roll is ideal for cold pitched roofs with accessible loft spaces. It's not suitable for flat roofs, warm roofs, or rooms in the roof conversions. Always ensure adequate ventilation remains after installation and that the loft space stays cold for optimal performance.