--- product_id: 410311938 title: "Manthorpe Pack 20 Roofing Felt Lap Vent Stops Loft roof Condensation/Attic Space Ventilation Airflow" brand: "ashbrook roofing" price: "Rp6289810" currency: IDR in_stock: true reviews_count: 5 category: "Ashbrook Roofing" url: https://www.desertcart.id/products/410311938-manthorpe-pack-20-roofing-felt-lap-vent-stops-loft-roof store_origin: ID region: Indonesia --- # 3,000mm² airflow per vent Fits joist centres 400-600mm Easy tapered lead-in install Manthorpe Pack 20 Roofing Felt Lap Vent Stops Loft roof Condensation/Attic Space Ventilation Airflow **Brand:** ashbrook roofing **Price:** Rp6289810 **Availability:** ✅ In Stock ## Summary > 💨 Breathe New Life Into Your Roof — Stop Condensation Before It Starts! ## Quick Answers - **What is this?** Manthorpe Pack 20 Roofing Felt Lap Vent Stops Loft roof Condensation/Attic Space Ventilation Airflow by ashbrook roofing - **How much does it cost?** Rp6289810 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.id](https://www.desertcart.id/products/410311938-manthorpe-pack-20-roofing-felt-lap-vent-stops-loft-roof) ## Best For - ashbrook roofing enthusiasts ## Why This Product - Trusted ashbrook roofing brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Maximize Roof Breathability:** Each vent delivers 3,000mm² of free airflow to combat condensation effectively. - • **Quick & Secure Installation:** Tapered lead-in and 3 felt clips ensure a snug fit—even on degraded felt edges. - • **Versatile Fit for Modern Roofs:** Designed to fit joist spacings from 400mm to 600mm, perfect for most loft refurbishments. - • **Cross-Flow Ventilation Strategy:** Install on both sides near eaves for optimal airflow and healthier attic spaces. - • **Retrofit Ready for Insulated Lofts:** Ideal for adding ventilation after loft insulation upgrades, preventing costly moisture damage. ## Overview The Manthorpe Pack 20 G630 Felt Lap Vent Stops are a retrofit ventilation solution designed to increase airflow in roof spaces with lapped felt or membrane construction. Each vent provides 3,000mm² of free airflow and fits joist centres between 400mm and 600mm. Easy to install with a tapered lead-in and secure felt clips, these vents help prevent condensation buildup caused by additional loft insulation. While not a standalone ventilation system, they are essential for improving attic airflow and maintaining roof integrity when upgrading insulation. ## Description The Manthorpe Felt Lap Vent is a refurbishment product designed to increase the amount of ventilation into existing roof spaces. Usually fitted retrospectively to properties with additional loft insulation recently installed, however the Felt Lap Vent will help to combat the problem of condensation build up in any roof space with a lapped felt/membrane construction. The specifier should ensure that the opening of felt laps on the property will not adversely increase the wind uplift load on the tiles/slates or the driving rain resistance of the roof, for more information see BS 5534:2003, 5.8.1 & 6.2.1.1. - 3,000mm² airflow per G630. - Can be fitted at joist centres ranging from 400mm to 600mm. - Easy to fit, the tapered lead in helps to slot the product between the felt laps. - The 3 felt clips help secure the product in place even if the edge of the felt is degraded. Installation: - Initially it is recommended that one ventilator be placed into the laps in every other rafter bay, down at low level (as near to the eaves as possible) and on both sides of the roof space to ensure a cross flow of ventilation. - In extreme cirstances, additional ventilators can be positioned in the vacant felt laps to increase the overall amount of ventilation provided. - Only one product should be positioned into a single felt lap. If additional vents are required, then more vents can be placed into the other felt laps within the same rafter spacing at higher intervals. - The product can be installed in roof spaces with rafter spacings ranging from 400mm to 600mm. - Each unit will provide 3,000mm² of free airflow into the batten void. - For further information on the recommended ventilation requirements for roof spaces refer to BS 5250 Code of Practice for Control of Condensation in Buildings. Review: Absolutely Excellent (so far), but expensive. Review: Fantastic! We recently moved into our first own home ## Features - The Manthorpe G630 Felt Lap Ventilator is a refurbishment product that is designed to increase the amount of ventilation into existing roof spaces with a lapped felt/ membrane construction. - The product is intended to be fitted retrospectively to properties that have had additional loft insulation recently installed. The vent will help to combat the problem of condensation build up caused by the extra insulation by adding additional ventilation into the roof space. - The product will not meet the requirement for roof space ventilation solely on its own it will only provide airflow through the felt laps into the batten void. - The product has been designed as a remedial solution to help overcome the build-up of condensation in the roof space, however like all products that open the felt lap to provide ventilation it does not meet the code of practice BS 5534:2014+A2:2018 6.2.1.1 - The specifier or user should be aware that the opening of felt laps on the roof may adversely affect the driving rain resistance of the slates, tiles or shingles, as well as increase the wind uplift forces acting on them. ## Technical Specifications | Specification | Value | |---------------|-------| | Manufacturer | Manthorpe | | Part number | G630 | | Item Weight | 1.63 Kilograms | | Package Dimensions | 30.1 x 23.4 x 12.3 cm; 1.63 kg | | Manufacturer reference | G630 | | Item Package Quantity | 20 | | Batteries Included? | No | | Batteries Required? | No | ## Images ![Manthorpe Pack 20 Roofing Felt Lap Vent Stops Loft roof Condensation/Attic Space Ventilation Airflow - Image 1](https://m.media-amazon.com/images/I/71Ax5y1ZuZL.jpg) ![Manthorpe Pack 20 Roofing Felt Lap Vent Stops Loft roof Condensation/Attic Space Ventilation Airflow - Image 2](https://m.media-amazon.com/images/I/41WXCfJYr2L.jpg) ![Manthorpe Pack 20 Roofing Felt Lap Vent Stops Loft roof Condensation/Attic Space Ventilation Airflow - Image 3](https://m.media-amazon.com/images/I/415q68i8WEL.jpg) ![Manthorpe Pack 20 Roofing Felt Lap Vent Stops Loft roof Condensation/Attic Space Ventilation Airflow - Image 4](https://m.media-amazon.com/images/I/81Od9IuMTEL.jpg) ![Manthorpe Pack 20 Roofing Felt Lap Vent Stops Loft roof Condensation/Attic Space Ventilation Airflow - Image 5](https://m.media-amazon.com/images/I/9171s5Zpl3L.jpg) ## Customer Reviews ### ⭐⭐⭐⭐⭐ Absolutely Excellent (so far), but expensive. *by M***8 on 13 February 2021* ### ⭐⭐⭐⭐⭐ Fantastic! We recently moved into our first own home *by B***D on 7 February 2018* ### ⭐⭐⭐⭐ Seems to do the job! *by W***L on 13 March 2019* ## Frequently Bought Together - Pack 20 Roofing Felt Lap Vent Stops Loft roof Condensation/Attic Space Ventilation Airflow - 10 x Felt Lap Vents Prevents Loft roof Condensation. Attic Space Ventilation - 10 x Manthorpe Felt Lap Vent, Roof Loft Ventilation, Cures Loft Condensation --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.id/products/410311938-manthorpe-pack-20-roofing-felt-lap-vent-stops-loft-roof](https://www.desertcart.id/products/410311938-manthorpe-pack-20-roofing-felt-lap-vent-stops-loft-roof) --- *Product available on Desertcart Indonesia* *Store origin: ID* *Last updated: 2026-05-09*