Tag Archives: weather resistant barrier

Worldwide Steel Buildings or Post Frame?

Loyal reader STEPHEN in AUSTIN writes:

“Mike –  I am so thankful for all the info you and your company have provided over the years. Your experience and knowledge have helped so many.  I especially love your promotion of bookshelf girts.  Every time I see a building framed within a building, I ask why?  Bookshelf girts make so much sense.  In my research, I also came across Worldwide Buildings, a competitor of yours.  They have a similar system:  https://youtu.be/yilRYwxukRQ

What would you see as some of the cons to their setup?  I am assuming cost is probably the biggest drawback.  Anything else?  I would plan on foam board (Possibly as a WRB as well that is taped) for any structure for a thermal break, whether it is steel or wood.  Any input you could give would be appreciated.”

Mike the Pole Barn Guru comments:

Thank you very much for your kind words. My goal is to see to it people avoid making crucial mistakes so they end up with buildings best meeting their wants and needs, and be as ideal as possible – even if they are not Hansen Pole Buildings.

Until recently my son Adam, his wife and our grandson lived in Austin, TX we are in a small world!

Bookshelf wall girts solve so many potential challenges and seem like a fairly obvious design solution to me. I also scratch my head when I see people framing up a house inside of a PEMB (pre-engineered metal building.).

I do know some of Worldwide’s staff, have met them in person, and they certainly seem like good people. I have no idea what sort of an investment comparison there is. Our buildings do come complete with engineer sealed drawings and sealed verifying calculations including a foundation plan, where these would be extras elsewhere. It does appear you would need some degree of precision in placing steel frame bolts. They also may have some additional expense involved with their slabs (usually PEMB slabs require a significant amount of rebar). 

Steel frameworks are great transfers of thermal energy – you would want to significantly isolate them with insulation having as great an R value as you would be using in your roof and walls. I see a lot of vinyl backed fiberglass insulation being applied on their website. This is not a very effective insulator as it gets crushed down to nothing at any purlin. For walls, you want a WRB (Weather Resistant Barrier) allowing any moisture inside walls to escape outward, so this vinyl backing would not be ideal. 

Foam board insulation should not be placed between framing and siding as it will allow your building’s siding to shift with wind and over time will cause deformation of screw shanks and/or elongate screw holes and eventually cause leaks. Ideally you would glue any foam insulation boards on the interior side of framing (to prevent thermal transfer from screws), taping all joints and sealing to concrete slab.

On their website they show girt clips on their frames for supporting 2×4 bookshelf wall girts – making for a fairly shallow insulation cavity. As near as I can tell, their packages do not include any lumber for girts, purlins, etc., merely steel frames, roofing and siding.

Thank you again for being an avid reader, please continue asking any questions.

Creating Extra Work in Barndominium Framing

Creating Extra Work In Barndominium Framing

A supposed downside of post frame (pole barn) buildings for barndominiums is having to frame a wall inside of an exterior wall in order to create an insulation cavity and a way to support interior finishes.

This myth is created and propagated by post frame kit suppliers and post frame builders who do not understand there is a solution – and a very cost effective one (in both labor and materials).

Rather than framing exterior girts (as shown in photo) and then adding vertical stud walls between columns, bookshelf girts can be utilized.

I’ve done several thousand pole buildings using this “bookshelf” or “commercial” girt method. I have two of them myself – in Northeastern WA, so I have a cold climate to contend with.

Use a commercial girt one size larger than wall columns (2×8 on a 6×6 post, etc.), setting commercial girts so 1-1/2″ hangs past the column’s exterior face. Wrap framing with a well sealed high quality Weather Resistant Barrier (for extended reading on Weather Resistant Barriers https://www.hansenpolebuildings.com/2016/01/determining-the-most-effective-building-weather-resistant-barrier-part-1/). 

As an alternative to using a Weather Resistant Barrier, closed cell spray foam can be applied to the interior face of siding as part of a flash-and-batt system https://www.hansenpolebuildings.com/2020/01/flash-and-batt-insulating-barndominium-walls/.

You will find this installation method compensates for any irregularities in column dimensions and creates a deeper insulation cavity. Side benefits – electrical can be run around column exteriors, without a need to drill through them to run wires. On walls a multiple of three feet in length, it also saves having to rip an edge of a panel off either the first or last sheet of steel on a wall.

In either case, block ends of bookshelf commercial girts solid against columns with what is called a “bearing block”.  Take 2×4’s or larger (depends upon engineering) cut 22-1/2” long to fit between commercial girts and install them flat against the post on faces where girts will attach.  Wide face of the block should be flat against the column and aligned with the post edge (not sticking out past column edge unlike girts).   Nail these girt support blocks to columns with a minimum of  two (2)10d galvanized common nails at each end (higher wind loads may require more nails).  This type of nailing is quick and easy and provides a solid support for commercial girt above blocks.  This is a far more solid and stable connection than toe-nailing. Toe-nailing is done by angling a nail upwards from bottom (or downwards from top) of commercial girt, at a 45 degree angle trying to catch enough post edge as the nail goes through to column to hold it there.  Toe-nailing is a very poor connection (and is subject to lots of installation errors).

For maximum cost effective R value, use BIBS insulation. I found it to be cost competitive with installed batt insulation, has a higher R value and completely fills all voids. https://www.hansenpolebuildings.com/2011/11/bibs/

I fondly remember a gal who called me one day asking for “canning jar shelves”…you know like you did before for us.”  Checking our records, I quickly discovered we designed commercial girts on their first building.  They liked them so much – they wanted them again!

No Leak Barndominium Windows

No Leak Barndominium Windows

Steel covered barndominiums, regardless of whether they are PEMBs, weld ups or post frame, if they leak it is in one of two places. First of these is when an errant roof screw misses a purlin or is improperly seated. Second of these is around windows.

As a builder I found a solution to most potential window leaks: https://www.hansenpolebuildings.com/2012/09/leaking-windows/

And taking it one step further, using pan (aka sill) flashings: https://www.hansenpolebuildings.com/2017/02/use-window-pan-flashing/

Sill flashing is a piece of preformed plastic flashing sloping away from window opening, so any water getting behind siding won’t collect under the window and cause problems. Rough openings (ROs) provided by manufacturers don’t generally allow for sill flashing thickness. Add an extra ¼ inch of height to ROs. 

Don’t start hacking away at WRB (Weather Resistant Barrier), especially if you’re new to window flashing. Do not make an X or I cut. Instead feed the window opening through WRB, cut along all four edges and remove the cutout. Do NOT wrap WRB into the opening. At the upper corners of the opening, make a slit six inches long upward at a 45 degree angle away from opening. Temporarily fold this newly created flap upwards.

Keep in mind WRB is your last line of defense against any water finding its way past siding. So if you do blow any cuts, make sure you patch them with WRB wrap tape.

Follow instructions below for installing an aftermarket pan flashing, such as SureSill™ Sloped Sill Pans™ (available at The Home Depot™). 

Install self-adhesive flashing tape (3M All Weather Flashing Tape 8067 or similar) around the window, overlapping tape onto flange and WRB. Do sides first, overlapping drainage skirt. Then across top overlapping side tapes. Cut tape to length with a utility knife and peel a little bit of backing free and stick it to the window top. Then lay it alongside the window and peel away the rest of the backing as you smooth it into place. Embed it with a laminate roller for a good seal. For best adhesion in cold weather, hit tape with a heat gun while you roll. 

Fold down previously created top WRB tab and tape 45 degree cuts.

Barndominium Brick Wainscot

Actual Brick Considerations for Barndominium Wainscot

With post frame buildings becoming a ‘rage’ for use as homes, barndominiums and shouse (shop/houses) alternatives to dress them up are quickly arising. Amongst these options are clients looking to have actual brick wainscot, as opposed to using a different color of steel siding, thin brick, or other cultured stone.

I have opined upon this subject previously (https://www.hansenpolebuildings.com/2018/08/brick-ledge-on-a-pole-building/), however it is now time to dive deeper into it.

Preparing an exterior surface of a post frame building wall for a brick veneer is a simple and straightforward procedure. This article will supply you with some helpful information if you are planning to install a brick veneer on your barndominium’s exterior.

First, term “veneer” can have a dual meaning. In construction terminology,“veneer” is applicable to any exterior finish material and this includes standard brick masonry installed onto an exterior wall. “Veneer” can also be taken literally to mean a thin superficial layer of material installed directly onto an exterior wall surface. There are many thin-brick wall systems available utilizing brick only ½ to 1 inch in thickness as opposed to a standard 4-inch nominal (3 ¾-inch actual) thickness. It typically consists of a thin layer of stone or brick mounted with adhesives directly onto a substrate material and is installed in panels. 

Step 1: Structural Support for the Brick Veneer

A fully assembled brick veneer is quite heavy and requires adequate structural support. Support is provided by a brick ledge as part of a foundation wall above wall column’s bottom collars. A decision to install a brick exterior is therefore made during conceptual design phases of your new barndominium’s construction. A brick ledge is constructed simply by adding a 6-9/16 inch thick concrete foundation wall outside your post frame building’s wall column. Ledge height will be six inches lower than top of finished concrete floor. Without an adequate structural support by a brick ledge, brick masonry is not an option for your barndominium’s exterior.

Step 2: Be Sure to Provide a one inch Air Space between Sheathing and Brick

Brickwork bears directly upon the concrete ledge, wide enough for both nominal width of brick and a building code required one inch air space. This one inch air space between sheathing and brick allows wall to “breathe” by providing an outlet for air and moisture. It also accommodates any irregularities in the wall surface.

Step 3: Install Weather Resistant Barrier

A weather resistant barrier (https://www.hansenpolebuildings.com/2016/01/determining-the-most-effective-building-weather-resistant-barrier-part-1/) must be installed onto sheathing to prevent water from entering the inner wall assembly since brick veneer itself is not water-resistant.

Step 4: Install Wall Ties to Anchor the Brick to Sheathing

Lateral support for brickwork is provided by wall ties or brick anchors. They generally consist of L-shaped strips of corrugated metal 1 by 6 inches long nailed through sheathing into wall girts (https://www.strongtie.com/clipsandties_miscellaneousconnectors/bt_tie/p/bt). Horizontal component of brick tie penetrates into brick veneer at a mortar joint. Ties are installed at every fourth brick course and at two-foot horizontal spacings.

Pre-Drilling, Housewrap, and Concrete Footings

Today the Pole Barn Guru answers reader questions about pre-drilling steel panels, the proper use of house-wrap and weather resistant barriers, as well as concern for the effectiveness or fresh concretes ability to withstand compression.

DEAR POLE BARN GURU: What size hole should I predrill in panels for the #12 diaphragm screws? Thanks! JOSEPH in KIOWA

DEAR JOSEPH: From Hansen Pole Buildings’ Construction Manual, Chapter 2:

 

“For pre-boring nail holes, 7/64” and 1/8” bits are required. Same size bit can be used for pre-drilling steel roofing and siding.”

 

DEAR POLE BARN GURU: Having read all of the info relating to insulating and am still confused. Main question is my entire 40×48 was wrapped in Tyvek including the roof. Now am trying to figure out if and how I can install a vapor barrier for the roof? Am planning to put in a ceiling with blown insulation above it and would like some options for the vapor barrier. Not sure if the roof Tyvek is a help or a hindrance. KEVIN in MALAD CITY

DEAR KEVIN: I’d like to find builders who are using Weather Resistant Barriers (WRB) under roof steel on post frame buildings, thinking they are installing a vapor barrier, and slap them silly. They have totally wasted their client’s hard earned money and, as in your case, have created a hindrance. Your only real solution is to remove Tyvek from under roof steel and replace it with an actual vapor barrier (one with a thermal break). You might see if a local spray foam installer would be willing to flash spray two inches of closed cell foam on underside of your building’s WRB.

DEAR POLE BARN GURU: My contractor poured concrete in each hole for a 30’ x 32’ pole shed and about 4 hours later started setting poles and put the entire frame up yet that same day. Can the concrete actually cure that fast or should I be concerned? PAUL in MITCHELL

DEAR PAUL: I am guessing you are talking about concrete poured for a footing pad under the columns.

Concrete gains its strength with time after casting. The rate of gain of concrete compression strength in higher during the first 28 days of casting and then it slows down. The compression strength gained by concrete after 24 hours is only 16%!

For practical purposes, a four hour old concrete footing is virtually worthless. Yes, you should be concerned.

 

IBC Requirements for Building Wrap

IBC Requirements for Building Wrap

When using a building wrap as a weather-resistant barrier (WRB), it must meet 2018 International Building Codes (IBC 1402.2) requirements of a WRB for water-resistance and vapor permeability.

A superior building wrap is air- and moisture-resistant, permeable, and has a high UV-resistance and tear strength. It should also be simple and quick to install, to limit damage during application. Using a high-quality building wrap compliant with IBC 1402.2  code creates a structure with a weather-resistant exterior wall envelope. A weather-resistant exterior wall envelope ensures a building is energy-efficient and healthy.

2018 International Building Codes (IBC) mandate buildings meet minimum requirements for exterior walls. IBC Chapter 14  IBC provides these minimum requirements, including wall coverings, exterior doors and windows, exterior wall openings, and architectural trim. Specifically, section 1402.2 states exterior walls must provide a building with a weather-resistant exterior wall envelope. Exterior wall design and construction must include a water-resistant barrier behind exterior veneer preventing accumulation of moisture within wall assemblies. Exterior walls must also include a way for water/condensation entering a wall assembly to drain/evaporate.

IBC specifies a few cases where a weather-resistant exterior wall envelope is not required.

  1. Code does not require a weather resistant wall envelope over concrete or masonry walls designed in accordance with IBC chapters 19 and 21.
  2. Code does not require a weather resistant wall envelope for exterior insulation and finish systems (EIFS) in compliance with IBC 1407.4.1.
    • IBC 1407.4.1 states for EIFS with drainage, water-resistive barrier must comply with IBC Section 1403.2 or ASTM E2570. IBC 1403.2 states attachment of no fewer than one layer of No. 15 asphalt to studs or sheathing, with flashing, must provide a continuous water-resistive barrier behind exterior wall.
  1. Exterior wall envelopes resisting wind-driven rain, including openings, joints, and intersections with a dissimilar material in accordance with ASTM E331 are not required to have a weather-resistant exterior wall envelope.

BENEFITS OF BUILDING WRAP

Applying a high-quality building wrap, like Barricade® Building Wrap, over sheathing, and behind siding, meets or exceeds IBC 1402.2 requirements for weather-resistant barriers. A properly installed building wrap creates a protective envelope against air infiltration and moisture into wall systems. A buildup of moisture within a building’s walls is problematic because moisture can lead to wood rot (caused by fungi) and expensive repairs. High moisture can also cause mold, unhealthy for structure occupants. Uncontrolled air infiltration lowers effective wall system R-value and lessens energy-efficiency and air quality of a building. To reduce air infiltration and stop accumulation of moisture within wall systems, along with meeting requirements of IBC 1402.2, design of a high-performing exterior wall must include a weather-resistive barrier, like building wrap.

Do Vapor Barriers Trap Moisture?

Vapor Barriers Trap Moisture?

Do vapor barriers trap moisture in walls of post frame buildings? They can, but only if they are installed on both sides of a wall insulation cavity.

Regular readers of this column will recognize a prevailing trend towards climate controlling both new and existing post frame buildings. An ability to control interior climate extends far beyond merely what one happens to be doing for insulation. It also includes what one does for weather resistant barriers and vapor barriers.

Insulating WallsThe purpose of a vapor barrier is to stop warm, moist, indoor air from infiltrating fiber-type insulation (think fiberglass or cellulose) during cold weather and condensing. Visible moisture or frost on the inside of a vapor barrier is either caused by a leaky vapor barrier or moisture migrating into the wall cavity from the outside. Leaky siding can cause this, and it often happens in basements that are apparently leak free. Vapor barriers are essential for any kind of insulation that air can pass through. Never do the really foolish act of slashing a vapor barrier that you find has moisture behind it or forgetting to install a vapor barrier in the first place. Today’s best vapor barriers prevent moisture from moving into wall cavities while also letting trapped moisture escape.

Recommendations below are for cold-climate construction. As a rule of thumb, if you have to heat your building more than cool it, this probably applies to your circumstance.

A weather resistant barrier (https://www.hansenpolebuildings.com/2016/01/determining-the-most-effective-building-weather-resistant-barrier-part-1/) will prevent moisture from entering a wall from outside of building. It also allows any moisture within a wall to exit. Pretty slick stuff, as it is smart enough to be directional.

Inside of this wall, once unfaced (recommended) insulation batts are installed, should be a vapor barrier (https://www.hansenpolebuildings.com/2017/11/vapor-barriers-post-frame-construction/). It is imperative this vapor barrier not have unsealed tears or holes. It should be sealed to floor and ceiling and any joints, rips or tears should be adequately taped. Where problems most often occur, with vapor barriers, is when penetrations are made for things such as electrical boxes. Properly sealing of these penetrations with closed cell spray foam from a can does more to prevent warm moist air to pass through into your post frame wall insulation cavity, than anything else.

 

 

 

Pole Barn Insulation, Part II

Continued from yesterday’s blog:

(1) Storage – if you ever believe anyone might ever in the future desire to climate control then provision should be made for making it easiest to make future upgrades.

At the very least a reflective radiant barrier (single cell rather than wasting the money for the extra approximately 0.5 R from double bubble), an Integral Condensation Control (https://www.hansenpolebuildings.com/2017/03/integral-condensation-control/) or sheathing with 30# felt should be placed between the roof framing and roof steel to minimize condensation.

If a concrete floor is poured (in ANY use building), it should be over a well sealed vapor barrier.

For now we will assume this building is totally cold storage. If it might ever (even in your wildest dreams) be heated and/or cooled include the following in your initial design: Walls should have a Weather Resistant Barrier (https://www.hansenpolebuildings.com/2016/01/determining-the-most-effective-building-weather-resistant-barrier-part-1/) between the framing and the siding. Taking walls one step further would be ‘commercial’ bookshelf wall girts (https://www.hansenpolebuildings.com/2011/09/commercial-girts-what-are-they/).

In the roof – have the trusses designed to support a ceiling load ideally of 10 pounds per square foot (read about ceiling loaded trusses here: (https://www.hansenpolebuildings.com/2016/03/ceiling-loaded-trusses/). Trusses should also be designed with raised heels to provide full depth of future attic insulation above the walls (https://www.hansenpolebuildings.com/2012/07/raised-heel-trusses/).

Make provision for attic ventilation, by having an air intake along the sidewall using enclosed ventilated soffits and exhaust with a vented ridge.

Any overhead doors should be ordered insulated – just a good choice in general as, besides offering a minimal thermal resistance, they are stiffer against the wind.

(2) Equine only use: Same as #1 with an emphasis upon the ventilation aspect.

(3) Workshop/garage and (4) Garage/mancave/house are going to be the same – other than whatever the client is willing to invest in R value, being the major difference.

Adding onto #1 for the walls the low end would be unfaced batt insulation with a 6ml visqueen vapor barrier on the interior. Other options (in more or less ascending price and R values) would be Mineral wool insulation as it is not affected by moisture (https://www.hansenpolebuildings.com/2013/03/roxul-insulation/),  BIBs (https://www.hansenpolebuildings.com/2011/11/bibs/), closed cell spray foam in combination with batts and just the closed cell spray foam (https://www.hansenpolebuildings.com/2016/07/advantages-spray-foam-over-batt-insulation/).

For added R value and a complete thermal break, add rigid closed cell foam boards to the inside of the wall.

Once a ceiling has been installed, blow in attic insulation.

For (4) a Frost-Protected Shallow Foundation (https://www.hansenpolebuildings.com/2016/11/frost-protected-shallow-foundations/) with sand on the inside rather than a thickened slab is an excellent and affordable design solution.

For insulation solutions which follow the roof line, the best bet is going to be the use of closed cell spray foam, as it solves the potential condensation on the underside of the roofing and does not require ventilation above.

In most cases, the steel trusses fabricated for post frame buildings are either not designed by a registered engineer, are not fabricated by certified welders or both – so it makes it difficult for me to recommend them as part of a design solution.

With scissor trusses, they can be treated the same as a flat ceiling would be, provided the bottom chord slope is not so great as to cause blown in insulation to drift downhill.