Return to Installation
Return to Forum
We are a quality metal roofing company in Canada, and have been wondering what is the best way to prepare a roof. To date, we have been installing ice and water shield at bottom 3 feet, in valleys and where there is flashing. The rest of the roof gets a quality underlay called Hydra. It is breathable, and moisture can evaporate. The plywood underneath greatly benefits from this.
My question is: would it be better to replace the ice and water shield with the quality underlay, which then goes over the entire roof?
Keep in mind:
1: Ice and water shield is not breathable, and does not allow moisture to evaporate.
2: Underlay breathability has nothing to do with vents, that exchange airflow in the attic.
3: The objective is to prevent ice damming.
In my opinion, what you're doing makes the most sense. Moisture in the attic (which may impact the plywood) will be carried to higher areas of the attic. Additionally, your current practice meshes well with building code requirements. Going against building codes puts your clients at future risk when they have inspections done for mortgages, insurance, etc. Thank you for representing the metal roofing industry so well.
If you would like to reply to this thread, please
If you do not have an Ask the Experts forum user account,