Totally agree about ventilation being a sneaky culprit. Had a similar experience myself—spent hours convinced I had a leak, only to find out it was condensation building up from poor airflow. Felt like an idiot after tearing half the ceiling apart, lol.
But speaking of insulation, has anyone tried spray foam under modified bitumen? I've heard mixed things. Some swear by it for sealing every nook and cranny, while others say it traps moisture if not done perfectly. Seems like it could either solve all your problems or create brand new ones... Curious if anyone here's had firsthand experience with that combo.
I looked into spray foam myself when redoing my roof, but honestly, the cost scared me off. Ended up going with rigid foam boards instead—cheaper, easier DIY install, and no moisture issues yet after 3 years... knock on wood.
Rigid foam boards can definitely be a solid choice (no pun intended), but I'd keep a close eye on them over the long haul. In my experience inspecting roofs, rigid foam can sometimes develop small gaps or shifting over time, especially if the installation wasn't perfectly snug. Those tiny gaps might seem minor, but they can lead to condensation issues down the road—moisture loves sneaking into those little spaces.
If you're comfortable getting up there every year or so to check things out, you should be fine. Otherwise, spray foam is pricier for a reason: it creates a continuous barrier that seals tight around every nook and cranny, significantly reducing the chance of moisture intrusion.
Not saying you made the wrong call—sounds like it's working great so far—but just something to consider as your roof ages. Keep an eye out for any signs of dampness or staining on the underside of your decking, especially after heavy rains or snow melts. Better safe than sorry...
Rigid foam definitely has its quirks, but honestly, I've seen it hold up pretty well if installed properly. A few things I've picked up along the way:
- Make sure the boards are staggered and taped at the seams—this helps reduce gaps forming later on.
- Mechanical fastening plus adhesive is your friend here; relying on adhesive alone can cause shifting down the line.
- If you're worried about condensation, consider adding a vapor barrier beneath the foam boards. It can make a big difference in moisture control.
- Spray foam is great, no doubt, but it's not always in everyone's budget. Rigid foam with careful installation and regular checks can be a solid compromise.
I've worked on roofs where rigid foam was still going strong after 10+ years, but I've also seen some rough installs that started having issues after just a couple seasons. Like you said, it's all about keeping an eye on things—especially after heavy weather.
One thing I'd add: if you do notice minor gaps or shifting down the road, don't panic. Often you can reseal or patch small areas without needing to redo everything. Just stay proactive and you'll usually catch problems before they become serious headaches.
Just my two cents from being up on roofs day in and day out...
Good points overall, but I'd also say don't underestimate the value of regular roof inspections. I've managed a few buildings with modified bitumen roofs, and rigid foam definitely does its job if installed right. But even the best installs can have issues pop up unexpectedly—especially after severe storms or heavy snow seasons.
One thing I've learned the hard way is to make sure whoever's installing it really knows their stuff. I've seen some rushed jobs where the seams weren't taped properly, and those tiny gaps turned into bigger headaches down the road. Like you mentioned, mechanical fastening plus adhesive is key—adhesive alone just doesn't cut it in the long run.
Also, if you're already going through the trouble and expense of insulating, it's worth considering reflective coatings on top. Not only does it help protect the insulation underneath, but it can also keep your cooling costs down in the summer months.
Just my experience though—every building is a bit different, so it's always good to weigh your options carefully before diving in.
