Fasteners for roof synthetic underlayment

[qmqmqm]

Hi everyone.

I see some roofers use regular staples for fastening underlayment.

However, some manufacturers' website recommend using plastic cap nails, citing it is more waterproof.

What is the purpose of choosing underlayment fasteners that are waterproof? All the shingles are nailed through the underlayment anyway, creating thousands of holes in the underlayment.

Cheers,

Paul

 

[Snoonyb]

While there are field penetrations of the asphalt base sheets, they are not field penetrated upon their installation and each successive layer overlaps the fasteners, as does foes each successive layer of roofing. Some specific base sheets require a washer.