125mm Knauf DriTherm Cavity Wall Insulation Slab 32 (2.18m2/Pack)

£29.78ex. VAT £13.66 per m2
£29.78ex. VAT
£13.66 per m2
±35 Sold in multiples of 35
±35 Sold in multiples of 35

Nationwide Delivery

Mon 15 Jun

Order by Monday at 2pm
  • 2days
  • 10hrs
  • 50mins
  • 33secs

Delivery & Returns Info

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Delivery & Returns Information

Delivery charges vary by product category and order value. Items may ship from different suppliers and arrive separately, so delivery charges can be shown per part of your order at checkout.

Standard (Nationwide) Delivery

Insulation, Plasterboard and Drylining Products
ORDER VALUE DELIVERY CHARGE
Under £400 £45 ex. VAT
Over £400 ex. VAT FREE

Express Delivery

Express Delivery - Insulation and Plasterboard & Drylining
ORDER VALUE DELIVERY CHARGE
Under £400 £90 ex. VAT
Over £400 ex. VAT £55 ex. VAT
Express Delivery - Timber & Sheet, Building Materials, Joinery and Gardens & Landscaping Products
ORDER VALUE DELIVERY CHARGE
Under £300 £50 ex. VAT
Over £300 ex. VAT £35 ex. VAT

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How delivery works

We work with a nationwide network of trusted suppliers. Items in your basket may be supplied by different suppliers and delivered separately. Where this applies, you will see delivery charges shown at checkout for each part of your order. We always aim to group products from the same supplier to keep delivery costs as low as possible.

Delivery areas

Delivery charges apply to mainland UK, excluding: AB, CA, CF, DD, DG, EH, EX, FK, KA, KW, KY, IV, LA, LD, LL, ML, NP, PA, PH, PL, SA, SY, TR, TQ and TD.

If your address is in one of these areas, we will contact you before processing your order to confirm any additional costs. We do not currently offer delivery outside the UK mainland.

What to expect on delivery day

  • Deliveries are typically kerbside.
  • Please ensure someone is on-site to accept delivery. For heavier items, help with offloading may be required.
  • Many building materials arrive on large vehicles. If access is restricted, a specialist vehicle such as a HIAB may be required and could incur an additional charge.

Why delivery can cost more than typical parcel delivery

Building materials often travel on larger vehicles and usually carry fewer drops per run than parcel networks. That is why delivery charges can be higher than standard e-commerce shipping.

Returns

Returns depend on what you have bought and whether there is anything wrong with it. For full details on eligibility, timeframes, and exclusions, please see our full policy.

View Full Returns Policy


Key Features

  • {{home}} Use in external masonry cavity walls
  • {{local_fire_department}} A1 non-combustible
  • {{thermostat}} 0.032 W/mK thermal conductivity
  • {{water_drop}} Water repellent
  • {{public}} Zero Global Warming Potential (GWP)
  • {{verified_user}} BBA certified

Technical Specification

Technical Specification
URN: 3002115
Product: DriTherm 32
Brand: Knauf Insulation
Material Type: Glass Mineral
Thickness: 125mm
Width: 455mm
Length: 1200mm
Sales Unit: Pack
Sales Unit Coverage: 2.18m2
Pieces Per Pack: 4
Fire Rating: A1 Non-Combustible
Thermal Conductivity: 0.032W/mK
Manufacturer's Reference: 715828

Product Overview

Full-fill glass mineral wool insulation slab, measuring 125mm in thickness, for use in masonry cavity walls.

Manufactured with a high recycled glass content and ECOSE® Technology, it delivers advanced thermal insulation while remaining vapour permeable, helping the wall construction to breathe.

With a thermal conductivity of 0.032 W/mK, it provides superior energy efficiency, enabling lower U-values to be achieved at reduced insulation thicknesses.

Rated Euroclass A1 non-combustible and fully BBA certified for all UK exposure zones, it ensures proven fire safety, durability, and long-term reliability.

At 125mm thick, the slab is designed for wider cavity walls in new build housing, offering a higher level of thermal performance than mid-range options such as 100mm. 

This increased depth helps achieve lower U-values in line with stricter energy efficiency targets, while still allowing full-fill installation in a single layer.

Features & Benefits

  • Non-combustible Euroclass A1 fire rating: Ensures maximum fire safety in external walls.
  • Thermal conductivity 0.032 W/mK: Reliable performance for wide cavity wall builds.
  • Water-repellent additive: Stops moisture transfer while staying vapour permeable.
  • 455mm width: Fits standard wall tie spacing for a close jointed finish.
  • Slabs knit together: Prevents air gaps and reduces thermal bridging.
  • Lightweight and cuttable: Simple handling and fitting on site.
  • ECOSE® Technology binder: No added formaldehyde and reduced embodied energy.
  • 125mm thickness: For wider cavities, delivering stronger insulation performance and supporting compliance with tougher Building Regulation targets.

Applications

  • Wide cavity walls (125mm): Designed for use in new build housing where cavity widths exceed standard dimensions.
  • New build housing: Provides high thermal resistance, supporting compliance with Building Regulation targets.
  • Masonry cavity external walls: Offers robust, full-fill insulation with proven long-term reliability.
  • Energy-efficient projects: Helps achieve lower U-values, contributing to improved EPC ratings.


Installation Guidance

  • Cut to fit: Slabs can be trimmed cleanly with a sharp knife for an accurate fit.
  • Close-butt joints: Ensure slabs are tightly butted together with no gaps to maintain insulation performance.
  • Keep dry before fitting: Store indoors or under cover to protect the slabs until installation.


Compliance & Performance

  • Euroclass A1 to BS EN 13501-1: Highest level of non-combustibility.
  • BBA certified for all exposure zones: Approved for UK use in severe weather locations.



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