Breathing life into loft spaces

Manthorpe Building Products is a company that specialises in and understands the topic of ventilation particularly well. The company has been developing innovative building products for the construction industry for over 35 years and has extensive experience in the use of plastics, as well as the expertise to develop and manufacture virtually all its products in-house and continues to invest heavily in new technology and production processes. 

Being one of the UK’s leading experts on roof space ventilation Manthorpe offers some unique and innovative solutions to ensure compliance with BS 5250 and maintain a condensation-free roof structure. 

For example, the Cowled Universal Roof Vent, or CURV for short, is possibly the only truly universal tile ventilator on the market. It can be used with a wide variety of single lapped roof tiles and slates, making it especially useful where the installer may not know what the roof covering is. It can be used with large and small format interlocking tiles, both flat and profiled in design, including deep bold roll styles of tile and, with a minimum roof pitch of just 12.5 degrees, it is one of the lowest pitch ventilators on the market, making it ideal for lean-to house extensions. The vent is fitted with a versatile flashing skirt which can be dressed to match the relevant profile of the roof covering and comes with an adhesive mastic backing which securely seals the flashing down to the roof. The hooded cowl protects the opening from the elements whilst providing an airflow path into the roofspace. An integral 4mm louvred grill within the cowl prevents the entry of debris and large nesting insects. For mechanical extraction or soil stack / vent pipe termination, the lower outlet is stepped to allow for 4", 5" or an oval 6" connection. The CURV has been fully independently wind-driven rain tested and is the perfect single-stock vent for merchants and roofers alike. 

Another innovative product in the Manthorpe range is the interlocking plain tile ventilator, designed specifically for use with small format twin, or duo plain tiles. This product incorporates a unique patented design feature, a sliding mechanism, to adjust its width to suit the different sizes of tiles available. This means that it is the only vent which suits all the versions of concrete interlocking plain tiles currently on the market. This makes it ideal for merchants and contractors, who only need to stock one interlocking plain tile vent product. 

The curved, in-line profile of the Manthorpe plain tile ventilator helps to maintain an unbroken appearance to the roofline at high or low level with a range of colours available to suit varying roof styles. The vent is suitable for roof pitches down to 22.5 degrees and is fully wind driven rain tested. The intricate path through the internal weathering geometry is designed to maintain a constant airflow gap of 6,000mm² whilst safely channelling any water out of the vent and on to the roof covering below. The 4mm louvred grill prevents the entry of debris and large nesting insects. 

When using the vent for mechanical extraction or soil stack / vent pipe termination, a 4" pipe adaptor can be fitted to the vent to connect to one of the GRPA Flexible Pipe range. 

Both these innovative ventilators can be easily connected to one of the Manthorpe range of GRPA Flexible Pipes to continue the ducting further into the roofspace. 

Addressing condensation in roof spaces is a common concern for homeowners, particularly during the colder months when moisture becomes more noticeable. The Manthorpe Felt Lap Vent offers a DIY-friendly solution for those experiencing condensation issues in attics and lofts. Typically, homeowners first notice condensation problems around November and December – often when retrieving Christmas decorations from the loft. These vents can be easily installed on the inside of the roof, providing a cost-effective approach to managing moisture build-up. 

Designed as a targeted remedial solution to address condensation in roof spaces, this product provides ventilation through felt lap openings. Users and specifiers should be mindful that while the product offers important moisture management benefits, its design involves opening felt laps, which may have implications for compliance with BS 5534:2014+A2:2018 6.2.1.1. Specifically, the ventilation approach could potentially impact the roof's driving rain resistance and wind uplift performance. 

For comprehensive guidance on roof ventilation and condensation control, professionals and homeowners are advised to consult BS 5250 Code of Practice for Control of Condensation in Buildings and BS 5534:2014 for detailed technical standards. 

For further information please visit www.manthorpebp.co.uk or email at mbp.care@manthorpebp.co.uk.