Tags: #buildingdesign #buildingenclosures #buildingenvelopes #buildingmaterials #buildingscience #materialsscience #tape

Polypropylene, HDPE, PVC, and TPO: is your tape/membrane backing compatible with your liquid flashing and sealants? 

It’s inevitable that tapes and liquid products will meet. And it’s usually at critical interfaces. Think window rough openings. If you do not know how the two bond and seal, you should. And be VERY careful with adhesion/compatibility charts offered by some manufacturers.

The above chemical categories are broad and non-specific. For example, the same liquid flashing or sealant may have different bond characteristics with two seemingly identical ‘HDPE’ backings – regardless of cure times & conditions. Backing formulations, film residues, surface energy treatments, and inks from those precious brand names – these are just a few of a myriad of variables. Furthermore, even when tapes and flashings are sold as ‘systems’, they are not always optimized. In other words, Flashing B may adhere and seal better than Flashing A on Tape A. 

And what about sealants and liquid flashings? They too have the same uncertainties. One silicone does not all make. Likewise with polyurethanes, butyls, and polyethers.

So when developing products, as with using them on the job site, it’s important to keep these things in mind – just some of the many nuances between success and failure.