As the worldwide major manufacturer and supplier of traditional metal roofing and metal wall cladding materials and historical restoration services, our foremost goal is the historically correct reproduction or restoration of old products with highest attention to longevity, durability and aesthetic. To achieve the full longevity of our products which have stood the test of time for centuries, it is essential that the associated products, like the Roof Sheathing and the Ice & Water Shield also be considered to match the performance of our products.
Consider this:
In the earlier days (more than a thousand years ago) when metal roofs (mostly copper) were starting to be installed on roofs for longevity, there were no engineered wood sheathing nor roof-underlayments known or used. Many of those copper roofs are still in use today with no sign of deterioration due either to the copper itself or to the roof structure or the roof sheathing.
Today’s building codes allow or sometimes require the use of engineered woods like OSB, Plywood, glulam etc. for the structural part of the building which must be separated from high heat sources like metal roofing. As this substrate is a glued together wood based material, it must be protected from hot surfaces of any kind which includes but is not limited to: metal roofing, slate, clay or concrete tiles etc.
The long term durability of those old roofs is due to the fact that the roof sheathing, the surface on which the roof is placed, was made of “real” wood and was installed with horizontal spacing between boards for allowing air to move in between.
These air spaces were there to allow the wood to dry out after condensation water accumulated during the temperature cycle of a day when the temperatures reached certain highs or lows resulting in condensation.
Condensation and related problems are still a large factor in today’s construction causing billions of dollars of damage each year. Today we rather try to fight the condensation by applying separation layers like underlayments, barriers, breathing or non-breathing – vapor permeable or non permeable membranes.
The condensation is not going away by looking the other direction or by not allowing it to drop onto the surface below it. It will form in almost any case and will be trapped if not allowed to either run away or to dry out.
Our roofing and wall cladding systems come with thousands of years old engineered details in them. As such, a roofing material more often than not becomes damaged from its underside (condensation) rather than from above (rain, sunshine. etc.). The Ice and Water Shield will only protect the wood from the condensation water, not the metal from forming the condensation causing possible damage to the roof if not taken care of appropriately.
If we only consider our metal roofing and wall cladding systems, they would be fine without any ice and water shield or any kind of separation layers in fact. To protect the surface underneath, however, since, again our major goal is longevity, we have to make sure that the structure underneath our metal roofing and cladding systems will be intact just as long as the metals themselves. Therefore, we suggest certain underlayments or separation layers according to the chosen products.
When factoring in the above information, the underlayments we consider must be suitable for general, high heat applications.
Standard high heat ice and water shield and/or roof felt products are absolutely suitable with our metal products. Ice and water shield will last a long time without the protection of roofing material, so there is no concern to have it installed and ready to go while still awaiting final roof system installation.
Ice and water shield will last longer than roof felts if left unprotected on the roof for a length of time.
Not sure what underlayment is right for you? Call us: 801-462-5264
Looking for more technical answers like this? Call us today for the metal roofing and cladding information and assistance you you need. We can help you by answering simple questions on the phone to full on design and engineering assistance, to boots on the ground installation techniques. Whatever level of involvement you require, we’re here to make your life easier, Plan your next metal roof with confidence! Call today!
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