Tag Archives: metal building insulation

Spot Problems with This Pole Barn Photo

Spot Problems With This Pole Barn Photo

One of my Facebook friends had posted this as a timeline photo as it brought back to her fond memories of a childhood spent frolicking in hay lofts. It was so bad, I just had to save it.

So, what’s wrong with this photo anyhow?

Obviously bird excrement over everything does not pose a structural problem, but one which I would have been trying to minimize, if not avoid. One thing which was leading birds into building – excellent nesting material provided by what was once a vinyl faced fiberglass condensation control blanket (aka Metal Building Insulation).

Long ago I had espoused about joys (or lack thereof) involved in installation of Metal Building Insulation (https://www.hansenpolebuildings.com/2011/11/metal-building-insulation-in-pole-buildings-part-i/). For those of you readers who did not click upon link and read it in full, suffice it to say birds love fiberglass.

Once condensation control blanket was torn apart – there was nothing left to prevent condensation from occurring below roof steel.

Moving forward, just glancing upon structure supporting hay loft, I would suspect a high degree of under design with only chance keeping it from meeting its demise.

All sorts of things are seen hanging from trusses. Amongst these are a block and tackle, which I suspect has been used to lift bales of hay into loft. Fortunately, individual small hay bales are relatively light, as I am pretty sure trusses were not designed to support added point load weights.

While not most effective structurally, trusses can be designed to be placed upon each side of a column – provided they are done correctly. Blocking should be placed between truss bottom chords, in order to prevent weak axis bending. A bare minimum would be every ten feet.

I see no web bracing, making this highly suspect. Older barns tend to have had bracing needs neglected. Single trusses (when placed not nailed directly face-to-face into a pair, they are single) require a great deal of bracing.

Knee braces are what I see as biggest structural issue. Not only are knee braces ineffective (https://www.hansenpolebuildings.com/2012/01/post-frame-construction-knee-braces/), but when installed improperly (as in photo) they are potentially throwing a load into roof truss bottom chords trusses were not designed to withstand.

Feel free to chip in with your observations.


Insulation Shows at Edge of Roof- Inside Closure Fix

The Insulation Shows at the Edge of My Roof- Inside Closure Fix 

Reader LARRY in SPRINGTOWN writes:

“We bought a Mueller building and hired their recommended installer. The roof went on yesterday. They did not use closure strips at the eaves so the insulation is visible on the outside of the building under the panel ridges where normally the closure strip would be visible. We do not have rain gutters. What is the solution besides jamming in glued pieces of closure strip at each exposed end of panel ridges?”

For those who are not from Texas and vicinity – Mueller Metal Buildings provides prefabricated all steel buildings as well as steel roofing. In looking over their website, it appears they do have a contractor assurance plan for residential steel roofing, however it would be highly unusual for them (or any company) to “recommend” an installer for complete building installation. They may have provided one or more names of installers for you to have vetted out on your own.

I will guess and say your building has metal building insulation under the roof steel (read my fascinating journey with Metal Building Insulation here: https://www.hansenpolebuildings.com/2011/11/metal-building-insulation-in-pole-buildings-part-i/).

Back in the day when this product was the condensation control of choice for roofs I experienced the same issues with installers who refused to follow instructions. The easy solution was, during installation, to run the insulation a few inches past the eave girt, peel off the insulation from the vinyl backing and fold the vinyl facing back over the eave girt. The trim at the top of the sidewalls would cover the white vinyl and all was good.

When the insulation remains exposed, the is the potential for the exposed fiberglass to wick rain water up and into your building (not fun).

So, what is the Solution?

DON’T PAY THE INSTALLER until the issue is fixed.

There are a couple of routes for the builder to follow, both of which involve removing the row of screws from the roofing into the eave girt/purlin.

Number one – do as recommended a few paragraphs ago, or number two – the insulation can be trimmed off at the outside edge of the eave girt/purlin and inside closure strips (https://www.hansenpolebuildings.com/2015/12/the-lowly-inside-closure/) can be placed to seal the space and keep the insulation dry.

Loosening Roof Screws

Help! My Roof Screws are Loosening!

Ask The Pole Barn GuruOur office gets all sorts of phone calls. Besides those clients who are potential investors in new post frame buildings, there are those who have made mistakes (or had builders make them on their behalf) and are looking for fixes.



One call came in earlier this year to Hansen Pole Buildings’ Designer Rachel, who wrote:

“Guy called wondering about buying insulation from us. He was looking for fiberglass. He asked some suggestions and said he has a little issue in his roof.  He has blanket insulation and said his screws are loosening.  I told him I thought it may be the insulation was too thick and the screw was not tight to the framing.  He understands but is wondering what the suggestion may be.  Wondering if he should replace all the screws?  Told him I thought it would still be an issue but not sure.  Thoughts?”

The caller’s building has a product known as metal building insulation under his roof steel. This insulation is most typically a six foot width roll of thin fiberglass insulation usually bonded to a white vinyl vapor barrier. This insulation is installed over the roof framing with the faced side down (fuzzy side up) then the roof steel is applied on top. Installed properly, with the seams tightly sealed (which rarely occurs) and any rips taped, it does make for a fairly effective condensation control.

It also makes for a lousy insulation solution, as the fiberglass is compressed nearly to nothing as it crosses each roof purlin. I’ve heard of builders selling metal building insulation as thick as six inches and trying to convince (and often getting away with it) clients they will achieve an R-19 insulating value!

All of this fluffy insulation wants to cause the roof steel to bend upwards in between the roof purlins, in some instances beginning to look like the Sta-Puff Marshmellow Man. Between this and the compressed fiberglass at each purlin – stress is laced upon each of the roof screws. If the screws are relatively short in length and/or small in diameter, they will eventually work loose (and cause leaks).

Reflective InsulationThe best solution (although time consuming) would be to remove the roof steel and the metal building insulation, replacing it with a reflective radiant barrier and placing the steel back on the roof using larger diameter and longer screws.

If the building owner is willing to accept the look of what he has, he could attempt a fix just by changing out the screws.

The best solution truly would have been prevention – not having used metal building insulation to begin with.

Insulation Dilemma

A reader writes (spelling, grammar errors included):

“When I built my barn I had 2″ insulation bats put between the outside framing and the tin. The side toward the tin is just open insulation. The inside is that heavy with plastic or whatever it is. I built with books shelve perlins on 2′ centers. Thinking it would make it an easy job to just fill those cavities with insulation. 

Where I’m confused is on the vapor barrier. We have a local business that makes insulation. Actually my insulation came from them. They guy there told me to just slice open the white vapor barrier and add insulation then use plastic over the added insulation prior to finishing my walls. So I’m just looking for affirmation that this is the correct way to go. Or other ideas and opinions.


From the description, I will assume the two inch insulation batts are what is known as Metal Building Insulation. This type of insulation is actually designed to reduce condensation issues in building which have steel roofing and/or siding applied directly over roof purlins or wall girts.

Metal Building Insulation is not an effective insulator, as the fiberglass insulation gets crushed down to nothing every time it crosses a framing member.

This particular building is designed with sidewall framing (girts actually, not purlins which are on a roof) placed bookshelf style to create an insulation cavity. The builder did not do his customer any favors and actually spent his customer’s money unwisely.

Moisture within the walls of a pole building can cause serious problems.  In the colder months, moisture tends to move from the inside to the outside of buildings.  As it passes through the walls, it may condense within them, causing the potential for rot and mildew.  In walls with insulation, the water may condense within the insulation decreasing its R-value.  In the worst case, moisture can actually freeze within the walls, accumulating until a thaw melts it and causes visible damage such as wall or ceiling staining!

A vapor barrier is designed to keep moisture in pole barns from getting inside exterior walls.  Batt and roll insulations usually come with a vapor barrier attached.  However, leakage can occur where the facings meet.  This is especially true if the facings are not stapled to the inside of the wall girts, but instead the insulation is just pressed into place or stapled on the inside of the girt (all too common of a practice with foil faced insulation).  For the best possible vapor barrier, supplement the facing by installing a 4mil or thicker clear plastic sheet over the inside of the entire framed wall before installing any interior finishes (like gypsum wallboard).

Never sandwich the insulation between two vapor barriers. For example, do not install insulation with the vapor barrier facing the climate controlled space and then put plastic sheeting, or some type of vapor barrier, across the outside of the framing. Since some leakage of moisture into the insulation in inevitable, it needs to be able to freely escape from the insulation to the outside world ….. not be trapped inside!


Metal Building Insulation in Pole Building Part II

If you didn’t read my yesterday’s blog – you may want to prior to reading today’s, which is the “rest of the story” on metal building insulation, commonly known as “MBI”.

My first experience installing MBI was not a fun one, in any sense of the word “fun”.

What no one warned us about were safety issues during installation. We should have been advised to wear protective gloves, a dust mask and goggles when working with insulation. Insulation is made of tiny fiberglass shards, which can cause serious irritation of the skin, eyes, nose and throat if you don’t take proper precautions. Instead, we spent several days with red eyes, itching skin and hacking up our lungs!

Now fiberglass itself is not some “magic” insulator, it is the dead air trapped in the uncompressed fiberglass which is doing the work. Smash the air out, and you lose R value. As far as an insulator, every time metal building insulation crosses a framing member, it is compressed to nearly nothing and loses its insulation value. People have this mistaken illusion “thicker must be better”.  Not true. Going to thicker products generally does not really add to the overall heat transfer resistance.

In years since, I’ve had clients tell me how a competitor proposed to insulate their new pole building with R-11 (3-1/2” thick) or even R-19 (6” thick) metal building insulation! First, I would hate to even imagine what the steel would look like, after trying to mash insulation this thick down and screw the metal through the insulation to the roof purlins. It would NOT be pretty. (read yesterday’s blog to see why).  Secondly, there is no way the fiberglass is going to come anywhere close to being able to fully expand between the roof purlins. Keep in mind the “product” does indeed have an R-11 capability (in the case of 3-1/2” thickness), when it is laid out in your driveway. As soon as it gets compressed, R values start to shrink. My educated opinion is a 3-1/2” thick product, in service in a pole building, is probably offering a true R value of between 2 and 4 – just slightly above nothing.

We (Hansen Pole Buildings) now partner with several lumber yard chains, providing pole building kit packages to their clients. Two summers ago I was visiting one of the lumber yard locations in Pennsylvania, in order to provide training to their staff. I went out into their warehouse to greet the store manager. Looking up at the roof of this pole building, I saw tattered MBI hanging down from between the roof purlins and hundreds of birds pecking at the fiberglass, to carry it away for nesting! Any hole in the vinyl at all, and a bird in the building, will result in exactly the same scenario being replayed – much to the chagrin of the poor pole building owner who now has no roof insulation, no condensation control vapor barrier under the roof steel of his building, and nothing but a mess.

In my over 30 years of experience, I can truthfully say I’ve never seen Metal Building insulation look to be a perfect “clean and neat” install product under roof steel.  Moreover, far too often I’ve visited older buildings where the inside view of this product “over time was enough to convince me it was not the optimal choice for pole buildings underneath steel.  Back up a few days to read other blogs where I discuss vapor barrier and reflective radiant barriers.  And stay tuned – for more on other insulation products!

Metal Building Insulation in Pole Buildings Part I

It was a cold morning….and I was working on one of the first pole barns I had ever built. With the roof all framed up, it was time to install the roof steel, or so I thought.

In a pile, on the ground, were bags of something white, about as large as an oversized water heater. Metal Building Insulation (in the industry also known as “MBI”). This not being my first rodeo (and me being young and cocky), I went over to pick up a bag and found it not only was heavier than Hades, but it was also soft and squishy, not the easiest thing to maneuver and I was going to somehow get it up onto the roof?

MBI is a thin fiberglass blanket (as thin as an inch), glued to a white vinyl vapor barrier. The fiberglass is usually six feet in width, and the vinyl is slightly wider, so as to create a tab on each side. Under ideal circumstances, with no punctures in the vinyl facing and the seams tightly sealed, it can be a very effective vapor barrier. What it is NOT, is a very cost effective method of insulating a pole building.

Back at the building site, I’m doing my best to alligator wrestle a bag of this stuff up a ladder and onto the top of the roof purlins. Winning the battle, I slice open the bag and find out this stuff smells bad, really bad….rather reminded me of when our male cat staked out his territory when we were kids. Ugh!

Once out of the bag, it took several of us to stretch it across the roof and get it into place to be able to install the roof steel over it. Into place involved unrolling these gargantuan rolls with the itchy fiberglass side up. To properly install, the lead edge needs to have several inches of fiberglass removed, the vinyl facing is then folded over and staples are put through into the top of the eave purlin. The roll is run up over the ridge, down to the eave on the opposite side, and the “remove-fold-staple” process is then repeated.

Failure to start a roll properly leaves bare fiberglass at the edge of the building. Strangely enough, when the roof is wet, water droplets can get to the edge of the roof steel and actually cling to the underside at the edge, rather than dripping off the roof. Exposed fiberglass can cause these droplets to be wicked up into the insulation – causing moisture problems inside the building.

The first roof steel panel was then placed on top of the fiberglass and screwed on. First thing I noticed is the thickness of the fiberglass caused the steel to bow up in between each of the roof purlins, rather than laying smooth. My thought was it looked rather like Bibendum (aka the “Michelin Man”) from the tire commercials.

When it was time to lay the next roll of insulation in place, I asked what I was to do with the tabs on the edges and was quickly admonished, “don’t worry about them”….so I didn’t. Only years later did I find out the true purpose of the tabs was to keep any warm moist air, from inside the building, getting through the seam and contacting the underside of the roof steel and condensing. Without an absolutely tight seal, moisture will form and now be trapped in the insulation between the roof steel and the vinyl vapor barrier – potentially causing deterioration of the roof steel from the inside.

In order to properly seal the tabs, they are to be held together, folded over once, and then stapled with stainless steel staples along the full length of the seam. I truthfully know of a total of zero instances where this has actually been done.

I believe I had mentioned before, it was cold at that jobsite. It had also been cold when the insulation rolls were delivered and thrown off the back of the delivery truck. Below 40 degrees, the vinyl facing becomes brittle and will crack – which is exactly what had happened in this case. After we had the roof done from the outside, we had to use insulation tape to patch literally a hundred or more cracks and tears in the vinyl facing on the inside!

From an installation standpoint, nothing involving MBI could be thought of as being fun. Or, worse yet, profitable.  Come back tomorrow to hear the “rest of my story” on metal building insulation….