Tag Archives: A1V

Condensation Control, Mother/Daughter Addition, and Vapor Barrier for Roof

Today the Pole Barn Guru answers readers questions about condensation control in a small garage with a gravel floor, the possibility of adding a “mother-daughter” unit to her house, and “ribbed vapor barrier” for a shed roof.

DEAR POLE BARN GURU: Recently purchased a metal garage kit, 24X26. No insulation. Two garaged doors. Gravel floor with plastic under grave. I am getting condensation on some days, that makes my cars, etc have like a dew on them.

My rib looks to be 1” and 7” between ribs. How do you install a wall vent with the ribs? JODY in ALTON

Machine ShopDEAR JODY: First step is to take care of your source. Pour a concrete slab on grade with a well sealed 10-15mil vapor barrier underneath. As you have no thermal break between your warm moist air inside building and roof steel, have two inches of closed cell spray foam insulation applied to underside of roofing. You would be better served to vent eaves and ridge, than just gable vents. If gable vents are your choice, look for vinyl vents with a snap ring as they can be installed on ribbed steel siding.

Using inward vent base edges as a guide, mark area to be cut on endwall steel INSIDE, make hole cut square with steel sheet (vertical cut lines parallel to steel ribs). Cut hole with appropriate tools.
Push vent base through hole in steel from inside.
Note word “TOP” on base when positioning. Vents installed with top side in any direction other than up will allow water to leak into building.
While holding vent base in place, snap face into base from steel exterior by pressing firmly (this takes two people).


DEAR POLE BARN GURU: I’m interested in building an attached mother/daughter addition to my home. Do you have plans for that? Approximately 600-700sq ft. NANCY in MONROE TOWNSHIP

Floor PlanDEAR NANCY: Thank you for your interest in a new Hansen Pole Building. Every building we provide is custom designed to best meet the wants, needs and budget of our clients. We offer a floor plan design service for folks just like you: http://www.hansenpolebuildings.com/post-frame-floor-plans/?fbclid=IwAR2ta5IFSxrltv5eAyBVmg-JUsoPfy9hbWtP86svOTPfG1q5pGmfhA7yd5Q 


DEAR POLE BARN GURU: We are having a 50×30 all metal building. We were advised to get ribbed vapor barrier for roof. We have searched everywhere. Is it called something else? SHANNON in OLEAN

DEAR SHANNON: We are also not familiar with any product known as a “ribbed vapor barrier”. We would normally recommend use of roof steel with an ICC factory attached (https://www.hansenpolebuildings.com/2020/09/integral-condensation-control-2/). If this is not an option (or if you are using closed cell spray foam directly to underside of roof steel), next choice would be a radiant reflective barrier – look for six foot wide rolls with an adhesive pull strip attached for ease of installation.


Seal Walls, Fill for Compaction, and Condensation Control

Let’s close out the week with another installment of Ask the Pole Barn Guru! First up is a resolution to seal up a building, followed by assistance with compacted fill, and finally an alternative to spray foam to control condensation.

DEAR POLE BARN GURU: I purchased a pole building from you last year and there was an error that I wanted an insulated building. So I will be insulating this myself. What keeps all the drafts and bugs out at the roof eve and lower edge of side panels? I am doing house wrap on the exterior walls. MARK in MOUNT VERNON

DEAR MARK: Communication – we as humans do so much of it and all too often do not fully convey our intentions. I am just as guilty as any other person, so do not feel like you are alone in this. This is one reason we strive to do everything in writing, so both parties are clear on each other’s expectations.


Also, successful construction is not measured by how perfect things went initially, but rather by how challenges are solved to arrive at a great end result.

Your roof eaves should be sealed with inside closures, provided with your building package, to install between fascia board and roof steel, so should not be an issue there. If you have not yet installed siding, same inside closures can be placed at bottom of walls, on top of your Weather Resistant Barrier to keep any little critters from entering steel high ribs in your 1/4 inch space between base trim flat and bottom edge of wall panels.


DEAR POLE BARN GURU: I’ve worked with a Hansen Building Designer, ordered my building, and materials will start arriving in two weeks. Looking forward to it, but also a little bit ‘trepidated,’ as it’s my first post-frame build (I completely remuddled a 100 year old farm house at our last place, so that’s what I have for previous experience).

My question has to do with the compacted fill that goes onto my cleared site after the poles are concreted in. Is crusher run gravel appropriate, or is a different type of gravel recommended for better drainage (I’m not familiar with the options, so please be specific if so)?

Also, please see the attached photo of the cleared site along with a drawing I created based on what I *think* are the correct dimensions based on reading the Construction Manual and a number of your blog posts. Note that I’m planning on a 5″ thick concrete floor, and have indicated same in the drawing at exactly 5″. ED in SUMMERTOWN

DEAR ED: Awesome drawing! You should have no difficulties in assembling your own beautiful building, as I can tell you are already reading directions!

Crusher run should be adequate for your sub-base. Most important is to get any clay removed from within upper levels of your grade and to have good compaction. Top two to six inches of your fill should be clean and drained sand or sandy gravel, again well compacted.

Photos: https://hansenpolebuildings.com/uploads/polebarnquestions/7bea6f6c3d75e192515b8bd12303c72c.jpg


DEAR POLE BARN GURU: If not spray foam on the underside of metal roof then I saw you recommend reflective siding insulation. Would that suffice in lieu of spray foam?


DEAR DYLAN: My first alternate choice would be to use an I.C.C. (Integral Condensation Control) https://www.hansenpolebuildings.com/2020/09/integral-condensation-control-2/ easy to install and no seams to worry about. Next choice would be a Reflective Radiant Barrier – we have it in six foot wide rolls with an adhesive pull strip to seal joints. Contact Materials@HansenPoleBuildings.com for delivered pricing (rolls are 128′ long).




Installing Insulation, Properly Treated Posts, and a Slab Solution

The Pole Barn Guru helps with installing insulation in wet seasons, properly treated posts, as well as a solution to embedded posts when bedrock is present.

DEAR POLE BARN GURU: Hello. I am ready to install the insulation and metal on our pole building’s roof. I remember reading how it is important to install the insulation and roof when things are dry as to keep the insulation dry. We have recently moved into a rather wet early fall, and dry weekend days have seemed very illusive.

Do you have any expert ideas or advice that you may be able to offer us? I appreciate all of the very useful help and insight you’ve provided us numerous times already! BRAD in MOUNT VERNON

DEAR BRAD: You want to avoid trapping water between Radiant Reflective Barrier and roof steel, as it can lead to premature deterioration of roof steel.

A helpful hint – in rainy weather only place one run of barrier and if upward surface gets wet, towel dry it and immediately install steel roofing to cover.

Just one reason I now recommend using roof steel with an Integral Condensation Control: http://www.hansenpolebuildings.com/2017/03/integral-condensation-control/.

DEAR POLE BARN GURU: Opinion in using 9” x 25’ class #3 pressure treated utility poles as columns or posts? I have come across a grip of poles in coastal pacific Mexico. Pondering the use of them as my columns/posts in cabin and deck style construction. Their structural and dimensional properties suited for use as such? Thank you. CARL in ZIHUATANEJO

CARL: I personally would not want to use them as level of pressure preservative treating (as well as chemicals used) could very well be iffy at best, toxic at worst. Read more about utility poles in post frame construction here: http://www.hansenpolebuildings.com/2012/11/used-utility-poles/.


DEAR POLE BARN GURU: 26’ x 42’ pole barn planned. We hit rock 6” down. Builder now wants to consider option of to pour the 4” slab first and use post saddles to anchor the posts on top of the slab. He says “This is a good option and results in longer life of the treated posts. Included in this option is additional bracing on each post” Is this really a viable option???

Help! Thank you. VICTORIA in FAIRVIEW

DEAR VICTORIA: Unless your builder can provide engineer sealed plans for your building including his “solution” fire him now because he has no clue.

Why do I say this? A four inch thick concrete slab only will provide inadequate to mount a building to.

In photo of correct bracket below, concrete would need to be deep enough to have rebar entirely embedded in concrete:


While a properly pressure preservative treated column will last longer than any of us will be alive to witness, of course if it does not touch ground it eliminates potential of any decay due to ground issues.

Read more here: http://www.hansenpolebuildings.com/2016/12/attacking-pole-barn-rocks-holes/.


Pole Barn Bid, A1V Barrier, and Definitions

DEAR POLE BARN GURU: I am bidding on a simple 80×140 pole barn with 12′ sides. I can’t come up with something reasonable. What would you bid. I need help. Last time I did it wrong and it hurt financially. Thanks. JASON in MINBURN

DEAR JASON: As you probably found out on your last post frame building project, they are far more than just simple barns, especially when they get to this sort of footprint. Our buildings will not be the least expensive, as there is always going to be someone out there who is willing to sacrifice quality for price. What you will get is the best possible building value for your investment. You will be hearing from one of the Hansen Pole Buildings’ Designers shortly.

DEAR POLE BARN GURU: So I decided to put up a pole building for a garage. I bought a standing roof kit, 30×50 with 12″ eaves and steel trusses that are arched in the middle of the building, for future dreams of having a car lift. My trusses have brackets welded on them for my 10′ 2×6 purlins to run in. My question is, do I need some sort of vapor barrier in between my metal roof and my purlins? My purlins run horizontal, I plan to use vented soffit the whole way around the building, 2 gable vents, and it also has a ridge vent. I will frame inside underneath the lowest point of my truss and insulate above that. It will leave about a 16″ gap between my interior ceiling and the steel roof. Thanks for the help. BRYENT in OHIOVILLE

Reflective InsulationDEAR BRYENT: Yes – it is essential you have a vapor barrier between the roof purlins and the steel roofing. I would recommend using A1V (aluminum one side white vinyl inwards toward conditioned space. Hansen Pole Buildings has six foot net coverage rolls in stock for immediate shipment. These rolls have a tab on one edge which has an adhesive pull strip – so no rolls of tape to deal with.

Code does not allow for gable vents to be used in conjunction with eave and ridge vents. It is one or the other and I would pick eave and ridge for the most uniform ventilation.

DEAR POLE BARN GURU: What defines a pole barn? The last building I put up on my property is an all steel truss roof structure and the foundation has 3’x3’x3′ footings at each of the six columns. What is the foundation used? STEVE in PALMDALE

DEAR STEVE: Technically a “pole barn” is a post frame building. Below is the definition for a post-frame building system from ANSI/ASABE S618 Post-Frame Building System Nomenclature. This standard was written to establish uniformity of terminology used in building design, construction, marketing and regulation.

Lean BuildingA building characterized by primary structural frames of wood posts as columns and trusses or rafters as roof framing, Roof framing is attached to the posts either directly or indirectly through girders. Posts are embedded in the soil and supported on isolated footings, or are attached to the tops of piers, concrete or masonry walls, or slabs-on-grade. Secondary framing members, purlins in the roof and girts in the walls, are attached to the primary framing members to provide lateral support and to transfer sheathing loads, both in-plane and out-of-plane, to the posts and roof framing.”


Roof Trusses? Contractor Reviews, and Insulation Installation!

DEAR POLE BARN GURU: I would like to rip off my current roof of trusses that are made of 2x4s 2 feet on center with new one of mono-pitched trusses that are every 4-ft or less on center. The roofing material on top of the new trusses would be a SIP panel of some sort. The unfinished ceiling would be the bottom of the SIP panel. The house would have exposed trusses to create a loftier feel as the ceilings are currently too low. (house is 28 ft wide by 30 feet long)

Is this something that you can help with — the design & manufacture of the trusses/roof?


DEAR NATHAN: Your Building Department is going to require engineer sealed plans in order to issue a building permit for your project. As such, your best bet is to hire a local engineer who is experienced in wood frame construction to provide your plans. They should come out to your house and do a thorough investigation into the adequacy of the structure to support the loads.

Some thoughts to consider – SIPs are going to prove to be very expensive. You could create a more spacious feel by constructing a knee wall on top of one of the existing walls, then use I joists or parallel chord trusses – either of which can be insulated between to give an adequate R value.

DEAR POLE BARN GURU: How can I find independent customer reviews in Washington state for Pride in Construction. GINGER in TACOMA

DEAR GINGER: Getting independent customer reviews on any building contractor anywhere is a challenge, as most builders do not construct enough buildings to develop much of a track record either good or bad.

Here are the seven steps to not getting yourself burned by any contractor, follow these: https://www.hansenpolebuildings.com/2013/07/contractor-6/ and require a performance bond and you will greatly limit your risk of not getting the finished product you expected. Here is Performance Bond information: https://www.hansenpolebuildings.com/2012/07/contractor-bonding/.


DEAR POLE BARN GURU: I will be installing insulation under the steel roof.  Are staple guns the best choice for temporary stabilization until the roof is added?  What length staples?  Which gauge staples?  Narrow?  Electric, air or grip staple gun?  Recommendations?  I will be using metal tape to join each roll of insulation side-by-side.

Trying not to re-invent the wheel, that’s why I went Hansen of course. RALPH in KENNEWICK

DEAR RALPH: From Chapter 14 of the Hansen Pole Buildings’ Installation Guide: Using a minimum 5/16” galvanized staple, staple through insulation to eave purlin top. As an alternative to staples, 1” galvanized roofing nails (with the big plastic washers) also work well.

These fasteners are only going to be needed long enough to get a sheet of steel on top of them, so there is no occasion to get fancy at this juncture. I’ve found a tack hammer to be more than adequate.

Keep in mind, the one edge of each roll of A1V insulation has a pull strip on it, with adhesive under the pull strip. This eliminates the need to use rolls of tape to adjoin each piece of insulation.


Reflective radiant barrier in Pole Buildings

As I mentioned yesterday, once you decide what your “needs” are when it comes to insulation, you can begin to narrow down your choices.  Just knowing the “R” value is not enough.  Sometimes insulation is used in other ways – like a reflective radiant barrier.

We use a product which “just is what it is”.  Meaning, it’s not high on the R value, but the “use” is of far greater importance than true insulating value.

Our standard insulation is what is known as “A1V”.  This is a layer of closed air cells sandwiched between a reflective aluminum (A= Aluminum) facing on the exterior and a white vinyl (V= vinyl) facing on the interior. This product is “directional” when installed on a roof – it is better at preventing heat gain, than heat loss. Laboratory test results have given it values as great as R-14 against heat gain. Under no circumstances should you necessarily expect numbers close to this, or rely upon a reflective radiant barrier as the sole method of preventing heat loss or heat gain. The way I think of reflective radiant barrier is this: If you have a steel roof – it is a condensation barrier so it doesn’t rain on whatever I have in my building.

I have folks who tell me, “but I live in Arizona so I don’t need vapor barrier”.  Or they think because their “roof only” building where they are stacking hay underneath is totally open to the air underneath – it’s going to stay dry.  Think again.  No matter where you are, at some point in time the warm air rises from the ground after being bathed in sun all day. And when it hits the cooler temperature of the steel roof, the moisture condenses and yes, it will rain on you!

Another thing – because my newest building has a black roof which loves those sun rays, the aluminum facing reflects the heat and keeps my cooling costs down in the summertime.

There is also A2V – which is just what it sounds like: A=Aluminum, then 2 layers of air cells – and then V=Vinyl backing.  This is the insulation I have underneath my concrete floor to aid in keeping the heat – in the concrete and not end up trying to heat “halfway to China” as my Mother used to say.  The 2 layers of air cells are necessary from the standpoint of the bearing the weight of the concrete floor.  This time the aluminum side is “face down”, as the aluminum will react with the chemicals in the concrete. A2V is also pretty handy (easy to apply) around foundations, around water heaters and insulating garage doors.

One more product I want to mention is A2A – which as the name implies, has two layers of air cells between a layer of aluminum on both outer surfaces.  Once again, the layers of air cells are giving you two layers of tiny pockets of air to resist the transfer of heat through materials.  More layers of air cells means more layers of insulating value.  Back to the purpose of why you are using it – if indeed you are looking for some heavy duty insulation – A1V or even A2V alone is not the answer.  In combination with other products – you get the best of both worlds.

And this is why I wrapped my entire building in A1V, but then filled the attic and exterior wall cavities with BIBS® insulation.  My heating and cooling bills for this 7200 square accessory building are less than the costs for heating/cooling my double wide 2100 square foot 1994 home across the street.  Now that’s scary!  Back tomorrow with more on insulation – the itchy kind!