WMP®-VR Faced Metal Building Insulation
Strange, unusual or uninformed requests are part of the territory when it comes to the world of pole buildings.
Just today we received this statement as part of a request for a quote on a building kit package:
“I would like to line the entire building with MBI (2″ fiberglass with a WVPMR backing Metal Building Insulation)”
My long time loyal readers read of my exploits and experiences with Metal Building Insulation. For the uninitiated, here is a chance for some education (as well as a laugh or two at my expense): https://www.hansenpolebuildings.com/blog/2011/11/metal-building-insulation-in-pole-buildings-part-i/ as well as: https://www.hansenpolebuildings.com/blog/2011/11/metal-building-insulation/
In my humble opinion, the product the client was actually looking for is WMP-VR. WMP® is a registered trademark of Lamtec® Corporation. From their 260,000 square foot facility in Northeastern Pennsylvania, Lamtec has been producing laminated insulation facings for nearly 40 years.
WMP-VR facings has a white polypropylene film, laminated with a flame resistant adhesive to a tri-directional fiberglass/polyester reinforcing and a Kraft paper. With a perm rating of 0.09 this facing will be an excellent vapor retarder (read more about perm ratings here: https://www.hansenpolebuildings.com/blog/2012/11/house-wrap/).
The reinforced facing will aid in preventing rips and tears which, if under or unrepaired, would compromise the ability of the assembly to resist transmission of water vapor.
If the client’s only intent is to control condensation on the inside of steel roofing and siding, then this might be a solution. I would issue the caution of the possibility of noticeable “puckering” of the steel between framing members, due to the thickness of the fiberglass insulation.
More often than not, people have the mistaken idea this two inch thick fiberglass blanket of insulation is going to allow cost effective climate control of the space within the building. Fully expanded, the two inches of fiberglass are going to yield an R value of about 6.4. My opinion is this is better than nothing…..
Well, how thick is the fiberglass when it is crushed between a wood wall girt or roof purlin and the steel siding or roofing? If your answer is – “not very”, you are absolutely correct. And what is the R value of the now very small thickness of fiberglass?
Faced metal building insulations do have their places – this just happens to probably not be one!