# Permanent Leto Breathable Membrane – 1 × 50m

A highly competitive and robust roofing underlay, Permavent Black is a versatile vapour-permeable membrane that is also suitable for walling applications. An air-tight design solution, providing associated thermal benefits, whilst assisting with condensation risk in your project.  
  
**Benefits**  

-   **Wind uplift resistance:** 1–5 (taped lap) / 1–3 (battened lap)
-   **Water penetration resistance:** Class W1
-   **Water vapour transmission (sd):** 0.02m
-   **Tensile strength (MD):** 300 N/50mm
-   **Tensile strength (CD):** 200 N/50mm
-   **Nail tear resistance (MD):** 120 N/50mm
-   **Nail tear resistance (CD):** 140 N/50mm
-   **Low temperature flexibility:** -40°C
-   **Reaction to fire:** Class E
-   **Weight:** 145 gsm

## Details

- **Price:** 72.85 GBP - 88.88 GBP
- **Vendor:** PERMAVENT
- **Type:** Felts
- **Tags:** Building Materials, Felts, Local, Membrane, Roofing

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| 145gsm | 72.85 GBP | In stock |
| 175gsm | 88.88 GBP | In stock |

## Images

- Permanent Leto Breathable Membrane – 1 × 50m
- Permanent Leto Breathable Membrane – 1 × 50m

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> Source: [Carvers Building Supplies](https://www.carvers.co.uk/products/permavent-leto-145gsm-breathable-membrane-1x50-mtr)
> Updated: 2026-06-22