Roof Outlets and Accessories
b/s/t offers a full range of flat roof accessories, competent professional consultancy and design support. We work in 24 countries, tailoring everything to suit our customers’ needs for customised or special products. b/s/t stands for simple, tailor-made solutions, lasting quality and reliable service. Your projects provide our motivation.
Proud Stockist of:
Flat Roof Systems with Ireland's Most Comprehensive Range of Drainage Solutions and Roofing Accessories
Even the most advanced waterproofing membrane will fail catastrophically if rainwater cannot drain efficiently from the roof surface, yet drainage design remains one of the most frequently overlooked aspects of flat roof specification. QBM supplies the complete range of roof outlets, drainage accessories, and finishing components needed to create fully functional flat roof systems that shed water reliably throughout their service life.
Our Roof Outlets and Accessories stock includes rainwater outlets from leading European manufacturers like b/s/t and Harmer, edge trims and drip profiles from Italprofili, expansion joints, pipe flashings, walkway systems, and specialist accessories for every flat roof configuration. Whether you're specifying drainage for a compact residential extension or designing complex multi-level commercial roof systems, we supply the technical solutions and expert guidance that ensure proper water management from the outset.
The performance and longevity of roof drainage systems depend fundamentally on compatibility between outlets and waterproofing membranes, correct sizing for rainfall intensity and roof area, and appropriate detailing at critical junctions. QBM's technical team understands these interdependencies and can recommend drainage solutions matched to your specific waterproofing system, whether EPDM, PVC, liquid applied, or reinforced bitumen. Our b/s/t drainage range exemplifies best-practice design with outlets engineered for specific membrane types, incorporating integral flanges that bond directly to waterproofing layers whilst maintaining the flexibility needed to accommodate structural movement. For refurbishment projects where existing drainage proves inadequate, we supply retrofit solutions including raised outlets, sump formers, and overflow systems that upgrade performance without requiring wholesale roof reconstruction.
Material compatibility extends beyond outlets to encompass every roof penetration and termination detail where waterproofing integrity must be maintained. QBM supplies comprehensive accessory ranges including prefabricated pipe flashings for soil vents and ventilation terminals, expansion joint profiles that accommodate building movement whilst preserving watertight integrity, and edge trim systems that provide professional finishing whilst protecting vulnerable membrane edges from wind uplift and UV degradation.
Our Italprofili range offers particularly elegant solutions for edge details, parapet cappings, and architectural features where aesthetics matter alongside technical performance. Every accessory we supply carries appropriate certifications and manufacturer approvals for use with major waterproofing systems, eliminating the compatibility uncertainties that void warranties and generate premature failures.
Beyond basic drainage and waterproofing accessories, QBM stocks a comprehensive range of ancillary components that professional roofing contractors require to deliver complete installations. Our inventory includes walkway systems and protection mats for roofs requiring maintenance access, gravel retention grids for ballasted systems, green roof drainage layers and root barriers for vegetated assemblies, and specialist sealants and adhesives for complex details. We also supply tapered insulation systems and drainage composites that create the falls needed for effective water shedding on structurally flat decks, addressing one of the most common causes of premature flat roof failure. This comprehensive approach means contractors can source complete system packages from a single supplier, streamlining procurement whilst ensuring material compatibility throughout the roof assembly.
Quality Building Materials has built its reputation by maintaining the most comprehensive stock of flat roof drainage products and accessories in Ireland, eliminating the project delays associated with special orders or back-ordered components. Our Dublin trade counter provides immediate access to standard products, whilst our relationships with manufacturers enable rapid procurement of bespoke fabrications for non-standard applications.
We supply complete technical data sheets, CAD details, and installation guidelines for every product line, supporting contractors and specifiers in delivering compliant installations that satisfy both Building Regulations and manufacturer warranty requirements. Whether you're a roofing contractor pricing materials for tender submission, an architect specifying drainage capacity for building control approval, or a facilities manager sourcing replacement components for maintenance works, QBM provides the products, technical expertise, and commercial terms that support successful project delivery.
Got a Question? Find the Answer Here
Does QBM install roof outlets and drainage systems, or only supply materials?
QBM is a specialist roofing materials supplier and does not provide installation services. We supply high-quality roof outlets, drainage systems, and roofing accessories to professional contractors and roofing specialists across Ireland.
Our Dublin trade counter provides expert product selection advice, technical specification support, and drainage calculations to help installers specify appropriate materials, whilst your chosen contractor handles the actual installation. This focus on supply allows us to maintain Ireland's most comprehensive stock of flat roof drainage products and provide the technical expertise that supports successful installations.
How do I calculate the correct number and size of roof outlets needed for my project?
Roof outlet sizing depends on several factors, including roof area, rainfall intensity for your location, drainage run lengths, and whether you're designing primary drainage only or including emergency overflow provision.
As a general guide, Irish Building Regulations typically require drainage capacity based on rainfall intensity of 75mm/hour, with most residential flat roofs under 50m² adequately served by a single 70-90mm diameter outlet. Larger commercial roofs require hydraulic calculations accounting for multiple outlets, box gutters, and overflow systems. QBM's technical team can provide drainage calculations for your specific project or recommend appropriately qualified drainage engineers for complex commercial applications requiring detailed hydraulic modelling.
What's the difference between primary drainage outlets and emergency overflow outlets?
Primary drainage outlets handle normal rainfall and are connected to the building's rainwater drainage system. Emergency overflow outlets (also called spigot or scupper outlets) provide secondary drainage if primary outlets become blocked by debris or cannot cope with exceptional rainfall events.
Irish Building Regulations require emergency overflow provision on most flat roofs to prevent structural overloading from ponded water. Overflow outlets are typically set 50mm higher than primary outlets and discharge visibly at the building perimeter, so blockages are immediately apparent. Both outlet types must be sized appropriately and detailed correctly with the waterproofing membrane to maintain watertight integrity.
Are roof outlets universal, or do I need specific outlets for different waterproofing systems?
Roof outlets are not universal and must be compatible with your waterproofing system to maintain watertight integrity and warranty compliance. Different membrane types require specific outlet flange configurations, bonding methods, and sealing details.
For instance, EPDM outlets use rubber flanges that bond with EPDM adhesives or tape, whilst PVC outlets have welded PVC flanges, and bitumen systems use torch-applied flanges or two-part epoxy bonding systems. Using incompatible outlets is a common cause of leaks and voids manufacturer warranties. QBM supplies membrane-specific outlets from manufacturers like b/s/t and Harmer that carry approvals for major waterproofing systems, and our technical team can confirm correct outlet selection for your chosen membrane.
What maintenance do roof drainage systems require to continue working effectively?
Roof drainage systems require regular inspection and maintenance to ensure continued effectiveness. We recommend clearing debris from outlets and gullies at least twice annually, typically in autumn after leaf fall and in spring. Box gutters should be inspected quarterly on commercial buildings and after severe weather events. Remove all accumulated leaves, moss, and debris that could block outlets or restrict water flow. Check that outlet grilles remain secure and undamaged. Inspect overflow outlets to ensure they're clear and unobstructed. On green roofs or roofs near trees, more frequent maintenance may be necessary.
Many building owners establish planned maintenance contracts with roofing specialists to ensure consistent inspection schedules and prompt clearing of blockages before water back-up causes damage.