March 30, 2017

How to Make It Stick: Preparing Surfaces For High Performance Air Sealing

broom and cloth

A little housekeeping goes a long way.

We sell Pro Clima tapes because they are incredible products. They promise long-term airtightness that will last for 100 years, are highly flexible to stay airtight as your building moves and settles, and the solid acrylic adhesive involves no solvents, is moisture-tolerant, and is easy to apply. We could go on…

But the key to the success of Pro Clima tapes is that they are able to fully adhere to the desired surface. If that surface is rough or uneven, or if it’s covered in construction debris, dust and dirt, then the tape won’t be able to form an airtight bond. If the surface to which you’re taping isn’t airtight, then all bets are off. Also, the surface cannot be made of the same silicone that comprises Pro Clima’s backing strips and release paper… or it will release, as designed.

So how do you deal with these challenges to ensure that your adhesion is optimal, and that your building enclosure is fully airtight? With a little bit of extra care and attention, you can easily ensure the long-term performance and the permanent airtightness of your assembly.

Ensure a Clean, Dust-Free Taping Surface

dusty window corner

Pro Clima tapes will stick to dust, but dust isn’t airtight. Dusty window corners will compromise the effectiveness of the tapes.

Job sites can be messy. Construction generates a lot of dust and debris, and buildings-in-progress are subject to weather and exposed to the elements. The solid acrylic adhesive in Pro Clima tapes bonds to almost anything – which means that if you tape to a surface covered in dust and dirt, dust and dirt are exactly what your tape will adhere to. And dust is not airtight. This will lead to incomplete adhesion between the tape and the intended substrate, and can significantly compromise the airtightness of your building enclosure.

Silicone, grease and other slick fluids can also reduce the effectiveness of the tape.  These materials drastically reduce the surface energy of the substrate.  Surface energy is the sum of the small intermolecular forces that make bonding possible. So by reducing the surface energy of your surface, silicone or grease decrease the effectiveness of the bond.

But a little housekeeping goes a long way. Simply brushing the dust and small particles off of the substrate, or removing any grease, before taping can increase the effectiveness of the tape dramatically. Pay careful attention to corners, where dust can pile up and be trapped. Wiping with a damp cloth to ensure that the surface is as clean as possible will further enhance the effectiveness of the bond between the tape and the substrate. Just make sure the surface is dry before taping.

Use Primer on Uneven or Porous Substrates

Primer_application_area

Pretreating porous or uneven surfaces like wood or masonry with TESCON PRIMER RP ensures a smooth, airtight substrate for Pro Clima tapes.

Sometimes, even a clean surface isn’t ready for taping.  Surfaces that are rough, cracked, uneven, or porous – such as brick, masonry, OSB and foam sheathing – are riddled with gaps that can serve as little conduits for air.  Even if these materials themselves are airtight, their rough surfaces preclude the formation of an airtight bond to tapes.

In these situations, TESCON PRIMER RP works wonders.  Priming the surface creates a smooth, sticky, airtight substrate to which Pro Clima adhesive will easily form a lasting bond. Once TESCON PRIMER RP has been applied, you can immediately tape to the primed surface – no need to allow drying. The integrity of the bond between tape and substrate is essential to long-term airtightness. So when taping to rough surfaces like these, TESCON PRIMER RP can be make a decisive difference in building performance.

CONTEGA Adhesives: Attaching membranes at building joints

CONTEGA MULTIBOND 1

Applying two strips of CONTEGA MULTIBOND offers extra protection on particularly rough surfaces, and can help to mitigate the unevenness of the substrate.

Attaching membranes to adjacent surfaces at building joints can be tough, because the connection between the membrane and the building element at the joint must be airtight.  This is especially challenging if the surface is rough. Caulk will likely be the best solution – in which case we suggest either CONTEGA HF or CONTEGA CLASSIC, for a more traditional liquid-applied application. For more on the similarities and differences between the two caulks, take a look here.  ProClima also offers a unique alternative solution with CONTEGA MULTIBOND. If the membrane you’re attaching is vapor-closed and impermeable, caulk would never be able to fully dry. CONTEGA MULTIBOND is a pre-cured line of adhesive that is activated by pressure, just as with the adhesive in Pro Clima tapes. Once pressure is applied, CONTEGA MULTIBOND instantly bonds to both the substrate and the membrane – ensuring immediate and long-lasting airtightness. And it remains flexible for years to come. CONTEGA MULTIBOND is suitable for interior and exterior use.

Contega Multibond 2

The strong bond forms instantly when pressure is applied.

Because of its malleability, CONTEGA MULTIBOND can fill the cracks on an uneven surface for an airtight bond.  For particularly rough surfaces, two strips can be applied to one another for extra protection.  As always, it’s important to ensure that your surface is clean and dust-free before applying CONTEGA MULTIBOND.

CONTEGA MULTIBOND can be applied to a wide range of substrates, including plaster, concrete, masonry, roughly sawn or painted wood, OSB, and rustproof metal.  Although priming the surface isn’t necessary in most cases, an adhesion test can tell you whether pre-treating the surface with primer could increase the stability of the system.

DustIsNotAirtight

Sawdust isn’t airtight – so taping to it won’t be airtight, either!

MULTIBOND can be applied in temperatures as low as 5°F (-15°C), and once applied will perform from -40°F to 212°F (-40°C to 100°C).  Because summer roof temperatures in hot climates can reach as high as 75°C, that performance range is important.

Summing It Up

Pro Clima tapes are powerful products for ensuring the long-term airtightness of your building. Investing a little extra effort in making sure that they are applied properly can pay huge dividends in building performance and energy savings.  So be sure that your taping surface is clean and free of dust, grease and silicone, and that the substrate itself is airtight. Your blower door test will thank you.

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