Installing leak barrier over existing leak barrier for roof replacement
我们计划用GAF Timberline Ultra带状疱疹代替现有的屋顶。除了格蕾丝冰和水上盾泄漏屏障外，我们将使整个屋顶甲板清除所有以前的材料。据说Grace品牌是如此的粘合剂，以至于几乎不可能在不损坏屋顶甲板的情况下将其从屋顶甲板上取出。我们咨询了GAF的技术规格部门，他们验证了我们可以将一层安装到现有的泄漏屏障上。GAF向我发送了一个技术公告（请参阅附件），尽管允许在现有的上安装一层，但建议承包商尝试删除现有的。现有的Grace泄漏屏障从屋顶周围的屋顶边缘延伸6英尺，在山谷和山脊通风口和其他开口下方延伸3英尺。该公告建议通过将新的泄漏屏障超过现有的新泄漏屏障来羽化。这是可能的，因为先前的安装没有在整个屋顶甲板上或筋膜板上扩展泄漏屏障。该公告说，不兼容的泄漏屏障沥青化合物可以软化，流动和滴水，并可能导致筋膜，沟槽和建筑物的外部染色。你经历过吗？ Is the risk less with GAF’s Stormguard Leak Barrier (film surface) rather than with GAF’s WeatherWatch Leak Barrier (granulated surface)? I appreciate your advice.
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I've investigated this same issue with several self-adhering / self-sealing Ice Barrier roof underlayments. The best course of action to take is always install the same brand / model of Ice Barrier as the original one. Almost every manufacturer has a warning not to install their product over another brand and vs. vs. And there may even be incompatibility between different types of Ice Barrier from a manufacturer (granular / film capped - rubberized asphalt/butyl....)
So to be safe, if GCP Grace Ice and Water Shield is currently down on the roof, install the same brand.
This question is going to come up more and more as roofs installed in the 80's, 90's and early 2000s are replaced and the first layer of Ice Barriers gets covered over.
在接下来的几年中，我们将看到更多的第二个REOOF，其中已经安装了两层冰壁垒。在那些情况下，IRC要求我们遵循制造商的重新申请说明。我检查的所有制造商仅允许2层的冰屏障，然后必须将床单从护套上取出，或者必须将膜的屋顶护套粘合到粘合。
I think FL code may have a sensible installation requirement that supersedes MFG install instructions - they require non-adhesive underlayment be cap nailed to the roof at 12 in. oc before installing self-adhering membrane. That way it can be completely removed without removing the roof sheathing.
" they require non-adhesive underlayment be cap nailed to the roof at 12 in. oc before installing self-adhering membrane"
I'd never thought of that. A really good idea.
It would seem that this is adding a layer just to negate the adhesive. Why not just use a single layer without adhesive? Shingles create lots of nail holes, so some more to attach the underlayment shouldn't matter.
Jon,
That's a good point. As long as the membrane has the same fastener sealing properties as I&W Shield, securing it with fasteners rather than adhesive, makes no difference. I suppose you could also use I&W Shield and only peel a narrow strip of the backing paper.
If the ice and water shield membrane was installed using a primer, yes, impossible to remove without damaging the roof sheathing. If not, the adhesion of modified bitumen is very temperature dependent. Don't know your climate or season of work but that could change quite a bit how difficult and damaging removal of the membrane is.
Peter
Thank you all for your advice. Good points to consider.
假设您使用GAF品牌冰和水来维护保修，因为它们需要3个或更多的GAF品牌组件才能完成保修屋顶系统，那么沥青沥青没问题。从EPDM到沥青的过渡通常需要缓冲液，通常是铝。除非您使用冰n冰和水，否则你很好