Tag Archives: condensation control

Ceiling Insulation, Drafting Capabilities, and 24″ On Center Framing

This week the Pole Barn Guru answers reader questions about “ceiling insulation” for a roof rebuild, the capabilities of our drafting and proprietary pricing program, and “what percentage of pole buildings are 24″ on center?”

DEAR POLE BARN GURU: The birds have destroyed the front half of the ceiling insulation in our 40 x 60 pole building. We need a new roof and we plan to take out all the insulation when the roof is done. We don’t know what else to do because if we leave the insulation in the back half of the ceiling, the birds may destroy that also. What do you think? SHARON in STERLING

DEAR SHARON: Typically when I hear people talk about birds having destroyed pole building insulation I think of what is commonly known as Metal Building Insulation. Usually this is a thin layer of fiberglass with a white vinyl face – and once birds get started into it, there is no turning back https://www.hansenpolebuildings.com/2018/09/spot-problems-with-this-pole-barn-photo/

If you are doing a reroof, to control condensation your should look at ordering roof steel with a factory applied I.C.C. https://www.hansenpolebuildings.com/2020/09/integral-condensation-control-2/

 

DEAR POLE BARN GURU: I was curious on what program you use to make your plans? Does it do take off and quotes with the drawings? Can you design the interior also the exterior to make a shouse? TIM in NORFOLK

instant pricingDEAR TIM: Always a pleasure to hear from a “lumber guy”. Our blueprints are actually drafted individually on AutoCAD, however we are gradually transitioning to where most fairly straightforward work will be automated from our trademarked and proprietary “Instant Pricing” system. We searched everywhere trying to find a computer program able to actually accurately do a structural analysis of post frame buildings and found none existed. We created our own and added to it abilities to do real time quotes for any climactic condition and anywhere in America. Our program does quotes, invoices, material takeoffs, creates purchase orders and interfaces with our client data base.

While it can do interior walls, we opted to create a full service program for shouse and barndominium plans with a real person interacting via screen sharing so clients can watch their homes appear before their very eyes from the comfort of their homes.

 

DEAR POLE BARN GURU: What percent of pole barns are on 24″ centers? BRUCE in SXARTZ CREEK

DEAR BRUCE: There are numerous components of post frame (pole barn) buildings often placed 24 inches on center. Among these could be wall girts, roof purlins, sometimes roof trusses (most often seen with shingled roofs), floor joists or floor trusses over crawl spaces, basements and for second or third floors. One of fully engineered post frame building design’s beauties is there is no obligation to be at a specific spacing and materials can be utilized for their full structural capacities – making them extremely cost efficient.

 

 

Decisions, Decisions – Vapor Barrier for a Post Frame Steel Reroof

Decisions, Decisions – Vapor Barrier for a Post Frame Steel Reroof

There are few reasons to replace an existing post frame building’s steel roof, as properly installed it should last a lifetime. Among these reasons could be:

Tired of Existing Color
Old roofing was nailed on
Tree fell through roof

This last one actually occurred to our shouse (shop/house) when I lived in Northeast Washington!

Loyal reader and Hansen Pole Buildings’ client MIKE in COUPEVILLE writes:

Reflective Insulation“I am currently re-siding/re-roofing an existing pole building in order to match the exterior of the building I recently purchased from you.  This building is roughly 32 x34 and the roof purlins are 2×6 on end roughly every 2 feet.  I’m using Fabral’s grand rib 3 29ga for the roof and it will have fully vented soffit overhangs and a vented ridge cap.  I am trying to figure out what I’m going to do for at least a vapor barrier under the roof steel, I see you seem to recommend foil faced bubble insulation but that is not very common in my area.  I am seeing a lot of people using lamtec wmp-vrr (fiberglass insulation with a poly backing)  3″ thick and I believe they lay these wide rolls on top of the purlins and then place the metal roofing on top of that then screw down the roofing compressing the fiberglass insulation between the metal roofing and the purlins.  Have you seen this style of insulating before?  Do you think it is an acceptable way of doing it?  I see as killing two birds with one stone.  I may be insulating this shop in the future so if I do then the roof is already insulated plus I believe it acts as a vapor barrier which is the main reason to do it as I don’t want any condensation dripping down on the inside of the shop.  I live in the Seattle area if that helps to know what my climate is like.  Thanks in advance for your input.” 


Mike the Pole Barn Guru responds:

Our recommendation would be to order your roof steel with factory applied I.C.C. (https://www.hansenpolebuildings.com/2020/09/integral-condensation-control-2/).

Metal Building Insulation (fiberglass with a vinyl facing) is a decent condensation control, provided all of the seams are tightly sealed. It is a pain to work with, provides very little effective insulation value and makes your roofing pucker outwards between purlins https://www.hansenpolebuildings.com/2011/11/metal-building-insulation-in-pole-buildings-part-i/.

If it is too late for an I.C.C. then the radiant reflective barrier (https://www.hansenpolebuildings.com/2017/05/effective-reflective-insulation/)

 is probably your best option.  Order in six foot width rolls to minimize seams and make sure to get a product including a tab along one edge with an adhesive pull strip attached.

How Best to Use Metal Building Insulation

How To Best Use Metal Building Insulation

Loyal reader ANDY in SOUTH CAROLINA writes:

“ I read with interest the article “What house wrap is good for” on your website and would like to include house wrap on a pole building I’m currently planning to build in the upstate of South Carolina.  Typically builders in that area simply use 3” polypropylene faced fiberglass insulation between the wall girts and steel siding. My situation is a bit different than most I have seen in that my single story building will be 1500 sq ft total, with 900ft dedicated to garage and shop space, and 600 ft dedicated to a guest apartment. If I were to place house wrap between the girts and steel as I believe you recommend, could the 3 inch faced insulation simply be placed on the inside of the girts for the garage space, and significantly more fiberglass insulation used around the apartment – inside deeper cavities of flush walls?  

Thank you.”

For those of you who need to know, here is article referenced by Andy: https://www.hansenpolebuildings.com/2012/11/house-wrap/


Surprisingly there are a lot of builders who “sell” people on how valuable a benefit Metal Building Insulation is. Long time readers may recall my personal adventures with it: https://www.hansenpolebuildings.com/2011/11/metal-building-insulation-in-pole-buildings-part-i/

Three inch thick Metal Building Insulation makes for a very poor return on investment as every time it crosses a wall girt it gets compressed pretty well to R-0. If lucky, one might net an R-3 or so out of it. It also tends to cause steel siding to pucker outward between girts. Properly sealed, it does make for a decent condensation control.

My recommendation would be to place a well-sealed WRB (Weather Resistant Barrier) between all wall framing and siding. Use commercial style bookshelf girts to create an insulation cavity https://www.hansenpolebuildings.com/2020/05/how-to-install-bookshelf-girts-for-insulation/. Use unfaced batt insulation with a minimum 6 mil clear visqueen vapor barrier on the inside. For what you would pay for three inch Metal Building Insulation, you can completely fill your insulation cavities.

Quonset Hut Homes

With the proliferation of barndominiums, shouses and post frame homes there is always someone looking for a cheaper answer. I have found cheaper generally gets me exactly what I paid for – cheap. Well for some, cheap may be living in a Quonset hut.

Considering a Quonset building for your new home? Consider resale value – there are very few people who want to live in a Quonset!

You may have heard Quonsets advertised on television, radio, online (even on Ebay) and in  back of Popular Mechanics.

I came across this query from a gentleman from Wake Forest, NC, “I have found some really good deals on the local craigslist from private individuals who have bought them and never put them up for one reason or another.” He wanted, “…to hear anyone’s input, good or bad. Yes, there are a lot of horror stories out there about poor schmucks that got hosed trying to buy from some less-than-scrupulous purveyors of these structures, but like I said, I plan on purchasing from a private individual who already has it in his possession.”

Now all of this got me thinking, so I started my research. It turns out Quonset huts were named for where they were first manufactured – Quonset Point, Rhode Island. First built for our Navy in 1941, as many as 170,000 Quonset huts were produced during World War II.

According to Wikipedia, “The erection of Quonset huts has been banned in the US state of Alaska for many years due to so many already being in the state and the majority of those falling into disrepair and becoming environmental hazards.”

I’ve never been involved in construction of a Quonset hut myself, as my background is in conventional stick frame and pole buildings. Due to this, I relied upon the experiences of four people.

When I was a post frame building contractor, Jay and his crew subcontracted labor on several pole barns we sold. Jay also did concrete work. On his own, he contracted to do concrete and assembly of a Quonset for a golf course driving range not far from me. This building was 40’ x 60’ and they worked on it every day for a month. Jay’s comments were anything but positive about concrete requirements and he said, “I’ve never seen and installed so many bolts in my life”. Of course when up and done, it had no endwalls, so those had to be constructed, and round walls precluded anything from being attached to them (not to mention it was near impossible to insulate.)

This insulation issue brought me to a comment from a Bob in Paisley, PA, talking about a local feed store, “The feed store has had issues with theirs and the original owner said it was a bad choice. They had a company come in and spray adhesive type insulation to the entire inside. As the metal expands and contracts portions of the insulation failed to follow the same rates which in turn resulted in chunks of reflective insulation falling from the ceiling area. Condensation and drips formed after the insulation fell.”

A second experience was told to me by one of my oldest daughter Bailey’s friends. Her friend’s father bought a Quonset for a garage. The pieces for it lay in a pile next to their house for several years, untouched. He finally sold it.  I can only surmise from comments it was quickly discovered to be far too much work to erect it, once purchased.

Online, I found this post from a gentleman who was actually espousing how wonderful Quonset buildings are:

“One of the few frustrating things about our Quonset is water leaks. The shell itself is engineered to be completely watertight. But, as with most well-planned projects, reality has a way of challenging the ideal. After checking all the bolts and tightening a few, we were able to seal all but a couple of leaks. The remaining few were due mainly to small tears in the metal at the bolt holes caused by over-stressing the skin in an effort to line up holes. After we made these mistakes a couple of times we realized our errors and corrected them. But the damage was done. 

Our biggest problem was sealing leaks at the base, where the shell meets the concrete and where it ties into the base plate. We were advised to fill the void created by the shell meeting the channel with concrete, which we did. We also used a heavy application of caulking between the base plate and the concrete. In spite of this, when it rained, we had an indoor pool. We then caulked all around the concrete where it met the metal. It still leaked. We then coated the whole area with water-stop concrete, a kind of latex/cement material that is supposed to seal concrete and bond to metal…it still leaked. We caulked again…to no avail.”

Lastly, one of our former Building Designers, Paul, related from his personal history as a Quonset salesman. His words were, “Less than 50% of the ones sold, are ever constructed.”

My summation is – even if they were easy to construct, Quonsets generally come in a single color – galvanized. They are difficult to insulate, with condensation control certainly being an issue. The purchase price often does not include endwalls, and certainly not doors (and sometimes not even delivery). And, speaking of doors, how do door and window openings work with curved (or even extremely high ribbed) sides? In Bob’s words, “Unless you get one of the tall ones you end up with an area along each of the sidewalls that becomes unusable except for collecting junk on the floor. Then it can be a head banger along the wall whenever you walk directly toward it while looking down for the junk.”

If anyone has a great, glowing story about Quonset huts, I’d love to hear it, I really would.  Because so far, I’m not impressed.  But I am always willing to listen to….”the other side of the story.”  Obviously I’m looking for objective evidence from those using quonsets…not just those selling.

Condensation Control, Home Plans, and Grade Changes!

DEAR POLE BARN GURU: If I put double bubble under metal on roof for condensation control, then insulate bottom chord of trusses with white vinyl faced insulation , will this create a problem if I ventilate attic space ? Thanks. SCOTT in DUNLAP

DEAR SCOTT: You actually have several things going on here. First, single bubble reflective radiant barrier will do everything double bubble will, at a far lesser investment. The difference in the minimal R value is a fraction of one! Your building ceiling should not have an additional vapor barrier, you want the moisture from inside the building to be able to migrate through into the ventilated attic space. Blowing in an appropriate thickness of fiberglass or cellulose insulation will be far more effective, probably less expensive and will allow the moisture through. Make sure to have adequate intake at the eaves and exhaust at the ridge to be able to properly vent the dead attic space.

DEAR POLE BARN GURU: Hello!

Do you all also finish the interior of pole barns if we want it to be a home or would I contract that separately?

Thanks! TIFFANY

DEAR TIFFANY: Thank you for your interest in a new Hansen Pole Building. We provide the custom designed plans, materials delivered to your site and assembly instructions for the shell and load supporting portions of your new building only. Any interior walls and/or interior wall finishes would be up to you to contract for.

 

 

DEAR POLE BARN GURU: Can I build a pole building home in the side of a hill, where the back will be below grade and the front above. RICK in CLEAR LAKE

Post Frame HomeDEAR RICK: Most certainly you can. I have a post frame building on the back of our property outside of Spokane, Washington. The site has 12 feet of grade change across the 40 foot width. After excavating the area where the building would be placed to level, ICF blocks were placed 12 feet high along the southern wall, stepping down with the slope on the east wall, with the other two walls being “daylight” and utilizing traditional columns embedded in the ground. You can read more about my building here: https://www.hansenpolebuildings.com/2013/06/garage/

 

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.

Should a Treated Post Look Treated all the Way Through?

Welcome to Ask the Pole Barn Guru – where you can ask questions about building topics, with answers posted on Mondays.  With many questions to answer, please be patient to watch for yours to come up on a future Monday segment.  If you want a quick answer, please be sure to answer with a “reply-able” email address.

Email all questions to: PoleBarnGuru@HansenPoleBuildings.com

 

DEAR POLE BARN GURU: I am currently constructing a pole building. I’ve drilled holes through the columns for rebar hairpins to be inserted to tie the columns into the concrete floor. It appears the post isn’t treated all of the way through. What can I do? DRILLING DOUG

DEAR DRILLING: Pressure Preservative Treated lumber does not have to be treated all the way through to be properly treated. As long as the column is tagged as being UC-4B, the column is adequately treated for structural in ground use.

For rebar hairpin holes, after properly marking on every treated post, drill each one using a 5/8” bit. Galvanized re-bar is recommended. If not available, coat rebar penetrating column with an asphalt emulsion, or similar, to isolate re-bar from the pressure treated post. NOTE: #4 re-bar is ½” diameter. Cut re-bars into 5’ long segments and insert one through each column, centering the five foot length in hole. Bend rebar legs, by hand, to a 45 degree angle with skirt boards. Seal rebar, into bored holes, at each column edge with silicone caulking.

DEAR POLE BARN GURU: I read your articles on both reflective heat barriers and vapor barriers.  It seems they conflict somewhat in that for the vapor barrier article you suggest putting the vapor barrier between the purlin and the metal roof, but for a heat barrier you recommend a gap between the roof and heat barrier.  So how do I combine the two?  Would putting a double aluminum sided closed cell barrier like Prodex on the inside of the purlins (creating a substantial gap from the roof) work best?  Thanks in advance for your expertise. TRYING IN TENNESSEE

DEAR TRYING: Thank you very much for reading my articles. As long as the reflective radiant barrier is totally sealed, it should work quite well for both insulation and condensation control.

What House Wrap is Good For

Over the past three decades, house wrap has become a staple feature on millions of buildings. Wrapping a wood framed building in a protective envelope is a good building practice which helps combat a building’s worst enemies: water, moisture and air infiltration. House wrap behind a building’s siding is an excellent secondary defense against the weather.

House wrap is a weatherization membrane which provides a protective layer under a building’s siding and over the wall girts or sheathing. It is literally wrapped around a building, cut out around windows and doors and taped at the seams.

The unique, nonwoven-fiber structure of house wrap resists air infiltration and water intrusion, yet is engineered to readily allow moisture vapor to diffuse through the sheet, helping prevent mold and mildew buildup and wood rot. The fibrous structure is engineered with microscopic pores which readily allow moisture vapor to evaporate but are so small bulk water and air cannot penetrate. Siding, whether vinyl, wood, stucco, brick, or composite, does not completely prevent air and water penetration. House wrap is designed as a secondary defense to help manage a building’s wall systems.

R-Value ratings for insulation are only maintained as long as the air within the insulation stays still and dry. The Department of Energy estimates nearly 40% of a building’s energy loss is the result of air infiltration caused by wind driven pressures from the outside. The opposing forces of pressure between inside and outside walls cause heat and air conditioning to be virtually sucked from a building– through walls, ceilings, sill plates, sheathing joints, top plates, electrical outlets and every inch of the estimated half-mile of cracks in newly constructed buildings. As air infiltrates, it causes changes in temperature which require heaters or air conditioners to work harder. Constant temperature fluctuations also reduce comfort levels. Occupants feel too cold or too warm. Reducing air infiltration increases a building’s comfort factor.

Insulation can help increase the R-value, but it is only marginally effective in reducing air infiltration. When air infiltrates, the R-value itself can be reduced up to 60%. Adding thicker insulation won’t solve the problem. Stopping air from getting in, will.

Properly applied, house wrap helps reduce air infiltration, preserving R-values, conserving energy, reducing heating costs and creating a more comfortable interior.

The tighter the building, the more comfortable and efficient. Unfortunately, the tighter a home, the more susceptible to moisture problems which can cause mold, mildew and rot. So all systems need to be in balance–designed to manage water and moisture effectively.

There are two main ways water and moisture get into wall systems:

Bulk water intrusion from the exterior (rain and snow) can enter the wall and, if not allowed to dry in a reasonable amount of time, can raise the moisture content of the wood above 30% and cause rotting or mold and mildew.

Air transported moisture occurs when air leaks from the warm side of the wall to the cool side. Warm air will hold higher amounts of moisture than cold air. As warm air travels through a wall heading to the cold side, it will begin to cool and be forced to release moisture. This is called the dew point where condensation will occur. When there is a significant temperature drop across the wall, the dew point will occur somewhere within the wall. In the winter months the point of condensation is usually on the inside surface of the exterior sheathing. Moisture carried by air flow through the wall is deposited at the back side of the sheathing and accumulates. In hot and humid climates where air flow is traveling from the outside to the inside, warm moist air from the outside will be cooled on the way to the air conditioned inside, releasing moisture within the wall cavity. House wrap is a breathable membrane with microscopic pores which allow the moisture vapor to dissipate, helping to dry out a wall system to avoid damage.

Moisture Vapor Transmission Rate or perm rate of a material determines the ability for water vapor to diffuse or evaporate through the wall. The higher the perm rate, the more “breathable” the material is and the easier it is for water vapor to pass through. Materials with Perms below 1 are considered vapor retarders since the rate of moisture vapor flow through a 1 Perm material is so low there is essentially no flow. House wraps have Perm rates in the area of at least 58 Perms which is very open to allow moisture vapor to flow through.

What house wrap is not, is a vapor barrier or an insulation. I’ve seen instances where people have applied house wrap directly between roof purlins and roof steel, in an effort to control condensation. House wrap is quite permeable; any warm moist air which would rise to it will pass through to the underside of the roof steel and condense.

House wrap is great…if used for what it was intended for…a secondary defense against the weather.