Butyl Tape under Aluminum Zinc Roof in Hot-Humid Climate
Hello all,
We are located in a tropical climate (northern Honduras) and we regularly use Proclima products in our projects. Typically these products are installed with a wood batten rainscreen. However, being an unorthodox way to build, we get lots of pushback from clients, citing concerns about weight, rot, and cost.
My question is, could we skip the rain screen and instead install aluminum zinc roofing panels directly on top of our mento sarking layer using butyl tape for sealing the penetration through the structure? Drainage and ventilation is not our concern as the patterns on the panels allow for this, my concern is the heat melting away the butyl tape.
Any thoughts and recommendations are welcome. Thanks!
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Replies
Butyl tape is generally the best choice for higher temperature applications. It doesn't melt and flow at typical construction temperatures like asphaltic tapes do. You should be fine using it on walls in your climate.
This will be used in a roofing application, do you foresee any trouble in the case?
Alberto,
Without a gap between the membrane and the roof panels, what do you see the advantage of using the Mento sarking layer over a regular impermeable roof underlayment? The Mento layer is usually added below the battens to allow some drying into the ventilation gap. With no gap I'm not sure there will be enough drying to the exterior for the type of underlayment to matter.
Is eliminating the ventilated gap a good idea in a hot climate? I would have thought it helps cool the roof appreciably.
Malcolm,
The roofing panels have 1 1/2 " ridges and permit lots of ventilation and draining although much more limited than with a batten rainscreen. About 50% of the area is still able to ventilate and drain. We use mento because it is a high quality product and guarantees a seal when paired with the butyl tape, and because of its permeability.
Alberto,
Perfect. Makes sense. I should have known you would have those things figured out.