Smarter Warm Roof Design with Drainage Slopes II

[Shane Clarke] Kia ora, tēnā koutou katoa. My name is Shane Clarke and I'm the General Manager here at Nuralite. Welcome to webinar number 38 - part two of our series on tapered warm roof systems. If you missed part one you can check that out on our education page. This webinar is NZIA CPD accredited for five points - there'll be a survey at the end for those wanting credits. Today we're talking about tapered boards and how they solve problems. I'm joined by Peter and Hilton from Nuralite, plus Erin Hallett from Respond Architects and Yuan Tao who worked on our case study project. We'll do a quick recap of tapered warm roofs, then focus on a real problem-solution case study. There'll be time for Q&A at the end - use the Q&A function to submit questions. If we don't get to yours, we'll include answers in the follow-up document. Let's start with a poll about who's attending... Thanks for that. Now the recap: The Nuralite tapered warm roof uses factory-made PIR boards with 1-degree falls. Standard sizes are 1.2m x 1.2m starting at 40mm (Board A), increasing in 20mm increments to 120mm (Board D). An 80mm filler board resets the sequence. This creates drainage without complex substrate shaping. The system works particularly well for retrofits like our case study. Looking at the layout plan, we design valleys at 45° from outlets, stepping up from Board A to high points. Our software calculates weighted R-values, material estimates and potential waste. Early engagement helps optimize designs - like the Kaitaia Hospital project we'll discuss. Erin, tell us about this project. Erin: The Kaitaia Hospital project started April 2024, addressing two aging roofs identified in a 2020 assessment. The theater/kitchen building had ply substrate under timber/concrete, while the ward block was concrete. Both needed remediation but had to remain operational 24/7. Using tapered boards over existing roofs minimized disruption. For the ply substrate, we needed additional structural assessments to confirm it could support the new system. Nuralite was involved from the start - they visited site, helped scope tricky areas, and provided system design guidance. The overlay added falls to roofs with minimal existing slope while providing insulation where there was none before. Their tapered plans gave clear height references for perimeters and penetrations, accommodating numerous roof services. Shane: Peter and Hilton, how did you approach the tricky areas? Hilton: The concrete roof section was most challenging. Water originally flowed around a corner to a distant outlet, which would have created excessive height buildup if we followed that path. The brief required keeping existing cladding, so we added a new outlet in a suspended ceiling space below. Pete redesigned falls to work with this new drainage point. Peter: Normally we use single-layer 1-degree falls, but here we stacked two tapered boards to create effective 2-degree falls where needed. This maintained drainage while avoiding height conflicts with cladding. Site visits were crucial - seeing the 3D reality versus just 2D plans. The solution kept the building operational and avoided cladding removal. Erin: The existing outlets were kept where possible. For the new outlet, we were fortunate to have a suspended ceiling below for routing. Existing membranes (mostly paint-on types) were left in place. The original theater roof even had 1930s-era Windex roofing - a concrete tile with membrane overlay. Shane: For Q&A - existing falls improved from about 3-7% to consistent 1-degree minimums. The tapered system added R-5.1 insulation where there was none before. Lead times for taper plans are typically 2-3 days depending on complexity - all designed in-house at Nuralite. Regarding compliance, our 3PM CodeMark certification covers 1-degree falls (our boards exceed this). Facade engineers reviewed and approved the design. For membrane detailing at tricky upstands, we worked with existing windowsill heights rather than removing cladding. We'll follow up with unanswered questions in the transcript. Thanks to Erin and Yuan for sharing this case study showing how tapered systems solve real-world problems. Final polls are up about future webinar topics and if anyone needs project assistance. Thanks all for attending!"