Tag Archives: closed cell foam insulation

When Attic Insulation is Baffling

Proper insulation provisions seem to be one of the least considered items when it comes to post frame (pole building) planning.

Here is a case in point from reader JOHN in BEND:

“We have just built a 32’ x 48’ pole building with commercial GIRT construction, metal siding, 4/12 pitch metal roof, concrete floor, 12 ft ceilings located in the high desert region of central Oregon.  The building will be used as a training center for a sport shooting club, and only occasionally occupied/heated.

We plan to insulate the walls and (flat) ceiling with R19 fiberglass batts and cover both walls & ceiling with 5/8” drywall.  We have some questions/concerns about adequate venting for the attic area above the ceiling.  We had a vent-a-ridge installed along the entire length of the building (48ft which will provide about 5 sq ft of roof ventilation).  We are now installing 4″ round soffit vents to match the 5 sq ft ridge vent to provide airflow.  We had also planned on installing styrofoam soffit/rafter baffles to ensure the fiberglass batts didn’t block the natural airflow from the soffits.  Then we noticed that the purlins run horizontally very near to the soffits.  The styrofoam baffles appear to be designed for vertical facing rafters that will naturally channel air up towards the vents.  Now we are wondering if styrofoam baffles (and our venting scheme in general) will work properly and whether we need to also install gable end vents.

Thanks for the help. We are a volunteer organization and just don’t have the construction expertise.”

From your photo, it appears the ceiling joist closest to the inside of the wall is a 2×6 with airspace above it. If so, your R-19 batt insulation will still have airflow above it. The baffles you invested in should be returned for credit, as they are not applicable for a post frame installation with widely spaced trusses. 

Now your true challenge, R-19 insulation is woefully inadequate for your location. Your attic should have at least R-49 (https://www.energystar.gov/index.cfm?c=home_sealing.hm_improvement_insulation_table) which would be about 16″ of blown in insulation.

Normally I would recommend to clients to have raised heel trusses to allow for full insulation thickness. In your case, I would recommend the area in the three to four feet closest to the sidewalls to be insulated with closed cell spray foam on top of the ceiling, to the thickness of the ceiling joists, then blow in fiberglass for the balance of the attic. Do not use faced batt insulation.

Pole Barn Guru Blog Review

This is the third year the Pole Barn Guru blog has been in competition for the Best Construction Blog. Last year this blog was second in the world, tying for first in quality, however losing the popular vote. Part of this process is a review of each blog by Mark Buckshon of Construction Marketing Ideas (www.ConstructionMarketingIdeas.com).

Below is Mr. Buckshon’s review:

Hansen Buildings’ Pole Barn Guru: Practical information about post frame (pole barn) structures

By Mark Buckshon

 –March 23, 2019

The Pole Barn Guru is currently leading in the 2018 Best Construction Blog’s popular vote and unless there is a surprising surge from supporters of another blog by the popular vote’s conclusion on March 31, this blog will probably earn the popular vote win status.

There are reasons for this support — the blog combines depth and focus as a “go to” resource for post frame (pole barn) buildings; and it doesn’t avoid the challenges with these low-cost structures, often used for outdoor storage and as rural outbuildings.

I’ve been reading some posts, for example, dealing with issues relating to condensation and insulation, some initiated by questions from outsiders — that is folks who have a pole barn structure not provided by Hansen.

Rather than brushing off these external inquiries with a: “Hey, that’s not my problem” attitude, this blog provides some practical answers, even as it indicates the issues probably wouldn’t have been problems if they had been considered in the initial design and purchase.

That educational aspect makes this blog truly worthy.

Consider, for example, this question in a recent blog post:

Hello! 

I have a pre-existing pole building that I am having a ton of trouble with. It is partitioned into two rooms, the back room is heated to around 50F. The attic space/loft space has a lot of condensation and I cannot seem to get this fixed. I have tried a lot of solutions, none of which have worked. I know that you build these types of buildings so I am hoping that you can recommend someone who might be able to come in and look at this issue and help me with a solution that works. I have no idea what to do next and I am a local business owner – my business is at a standstill right now until I can get this issue fixed. If you can recommend any general contractor, or anyone who might have expertise in pole buildings who I can contact I would greatly appreciate it. 

Thank you so much!”

The question is posed after a brief introduction:

Long time readers should be thoroughly drenched with solutions to condensation issues by now. As post frame construction has moved off farms and into suburbia, climate control has brought with it a plethora of condensation challenges.

So, what are the answers?

To control your condensation challenge you need to either remove warm moist air from inside your building, prevent this air from becoming in contact with surfaces at or below dew point, heat and/or ventilate. Here’s a brief summary, followed by solutions specific to your case: https://www.hansenpolebuildings.com/2019/02/how-to-reduce-condensation-in-post-frame-buildings/.

If you do not have some sort of thermal break below your pole building’s roof steel – two inches of closed cell spray foam should be applied. This process will be best done by a professional installer. Make certain to not block ventilation intake and exhaust points.

Unless you know for certain a vapor barrier was placed under your building’s concrete slab, seal the floor.  https://www.hansenpolebuildings.com/2019/02/how-to-properly-apply-post-frame-concrete-sealant/ 

and https://www.hansenpolebuildings.com/2018/11/siloxa-tek-8505-concrete-sealant/.

Vent any dead attic spaces. https://www.hansenpolebuildings.com/2018/03/adequate-eave-ridge-ventilation/.

Heating your building to a temperature above dew point will also solve this issue. Avoid heating with propane, as it adds moisture to the air.

Now in my opinion, that sort of detailed, practical advice shows how an effective, consistent and useful blog can provide real value to clients and potential customers alike (and serve a general community purpose, even for people who will never purchase a thing from Hansen.)

This value translates to search engine effectiveness and of course a reputation for knowledge and service. If you are thinking about purchasing a post frame structure, for example, I’m confident after reading through the relevant blog postings you’ll have the confidence to ask the right questions and share the site/usage observations to ensure that the structure serves its purpose and problems such as condensation or poor insulation don’t occur in the first place.

Development of My Post Frame Cabin Plans

Thank you to Hansen Pole Buildings’ Designer Rick Carr for today’s guest blog.

Development of my Cabin Plans

I have been looking at both open land and existing “cabins” in the Southwestern part of the State of Wisconsin where I do a lot of fly fishing for trout in anticipation of eventually retiring.  I want to be able to go out and stay for four or five days to a week on short notice without having to worry about where to stay while having my own personal items and gear there waiting for me along with the ability to just fire up the grill for dinner rather than going out every night.  Space for friends bearing Bourbon to visit was also a consideration.

Existing Cabins were disappointing to say the least, either upper level sleeping (which doesn’t work for over 65 year old guys) or tiny showers, filthy kitchens. There was always something very wrong; and all this with a limited budget.  It became clear that building would have to be an option unless I was going to settle in some area or another. With my five year plus experience as a Senior Building Designer with Hansen along with two years on a post frame building construction crew in my youth, I knew that if I had to build, it would be a post frame building.

Last spring I found and bought a nine acre parcel with 1,600 feet of the headwaters of a crystal clear spring creek full of brook trout flowing through.  I have three of the four permits that I need to allow me to put in a driveway and culvert across the creek and the wetlands to the high ground building site on the far side.  The front porch/deck will have great views of both sunrises and sunsets looking over the valley.

Some of the deciding factors for post frame were, knowing that a post frame building can be built to be extremely well insulated for climate control, knowing the cost advantages, knowing the longevity, knowing the framing system, and the fact that I can do a lot of the building myself for additional saving. I have also been developing relationships with the local Amish community who I know that I can hire for reliable economic labor.

About Hansen BuildingsI plan to construct the building so that it can be used as a full time residence for resale value, although that is not my intended use.  Relative to a well-sealed and insulated building, I intend to use BIBS insulation in the walls using 2×8’s in a 7 ½ inch cavity and closed cell foam insulation on the underside of the roof purlins designed for drywall to create a vaulted ceiling in part of the cabin.  This combination will make an extremely tight building making it more comfortable and less costly to heat.

The cost advantages of post frame start with not needing a full foundation and the costs of a full foundation.  Then post frame is very efficient in terms of lumber usage. Over the years I have had client after client send finished building pictures with the tiniest of scrap piles in the background.  My experience and familiarity with our construction manual gives me the confidence that I can act as the general contractor and jobsite supervisor while hiring local Amish builders for more cost savings.  I have a lot of DIY experience so a post frame building from Hansen will allow me to finish most of the interior myself for additional savings.

I am not concerned with how long the building will last, rotting of posts, as some people are because I know that the testing of current pressure treating is good for 70 plus years.  At the age of 66, I will be able to use this Cabin for as long as I can manage, ten to fifteen years, and still have many years remaining of useful life for resale value.

My next consideration was a heating and insulating plan.  My experience as a Building Designer tells me that it is very important to have a heating and insulating plan before ordering a building to make sure that the correct options are designed into the building and are on the Engineer Sealed Plans, especially on a post frame building to be used as a residence.  I have a friend that has a similar building/cabin in the fishing area. A year or so ago on an early spring fishing trip, he asked me to stop in and check on his cabin that was last used back in the prior fall. I walked in and there was no dust, after no one being there for months. I was convinced at that point that I wanted radiant floor heating, but being close to a flood plain, (last year there was a 100 year flood in the valley).

I knew that I wanted a crawl space, which would give a few extra feet of protection in the event of a 150 year flood.  The other advantage is that the crawl space would provide access to plumbing in the event of a problem or change versus having the radiant floor heating and the plumbing encased in the concrete floor. The drawback is that a radiant floor in a building with a crawl space adds other design issues.

Come back tomorrow as Rick investigates his pole barn cabin’s crawl space issues, and asks for Mike the Pole Barn Guru’s wise advice.

Metal Building Insulation

Building Has Metal Building Insulation

Hansen Pole Buildings’ Designer Rachel received an inquiry from a client whose existing post frame (pole) building has metal building insulation.

Rachel sent this to me:

“STEVE would like some advice on insulating.  He has a Cleary Building which has blanket insulation in the walls and roof and he would like to insulate over the top of this insulation and wondered if there would be issues.   

Steve mentioned that as your standing in the building you see the white vinyl on the inside.  Is there vinyl on both sides?  If not, shouldn’t the vinyl by facing the steel?

Any information or assistance you can give him would be appreciated.”

Mike the Pole Barn Guru writes:

I am not much of a vinyl faced metal building insulation fan to begin with (read more here: https://www.hansenpolebuildings.com/2011/11/metal-building-insulation-in-pole-buildings-part-i/]. Even though I have it in roofs of my two older personal post frame buildings, it isn’t a product I would use if I were to construct a new building for myself.

Problems would come from having insulation sandwiched between two vapor barriers.

I would do this personally –completing each wall individually, I would remove wall steel, remove  wall metal building insulation. Cover each wall with a Weather Resistant Barrier (like Tyvek) and reapply wall steel. Spray two inches of closed cell foam insulation upon the inside of the wall steel. If full wall thickness bookshelf girts were not used in the walls (flush or extending inside of columns), another set of girts should be added to the inside surface of columns. Your engineer of Record (engineer who sealed your building plans) should be consulted to determine proper size and spacing of girts. Once installed, fill insulation cavity completely using BIBs. Glue two inches of rigid closed cell foam insulation board, taping all seams, to the inside face of girts. Glue interior finish (typically gypsum drywall) to the inside of foam boards.

PBG NOTE ADDED: Hansen Pole Buildings’ Designer Rick Carr aptly pointed out to me WRB (Weather Resistant Barrier) purpose would be defeated by spray foam application. Correct application should be one only, however only after metal building insulation removal.

For your roof, provided trusses are adequate to support applicable dead loads, I would install a truss bottom chord level ceiling. This would allow insulation to be blown into dead attic space. In order to achieve adequate insulation above the sidewalls, it may prove necessary to use closed cell spray foam insulation above the ceiling in areas closest to the sidewalls. If eaves have ventilated soffits, ensure an inch or more of free air space exists between insulation and roof deck (or metal building insulation). Appropriate ventilation must be provided in dead air area above insulation.

 

How Insulation Works

I so enjoy clients who truly care about the outcomes of their post frame buildings. In this case, I’ve been back and forth with reader Eric and today we are discussing how insulation in walls works.

Eric writes:

“Mike,

Thanks again for the input. I read those articles you mentioned on the BIBs and the white liner panels. The liner panels are very common and popular around here but the article had very good points and gave me more to think about. As for the insulation, I was not familiar with the BIBs system and was impressed. I have done some more reading and reached out to a few contractors for quotes on the BIBs system. I do prefer to do things myself whenever possible however, so the option of installing fiberglass myself is still on the table. This is where I still have a question. You mentioned to fill the entire wall cavity with unfaced fiberglass and then cover with Visqueen. Is there an issue if the cavity is not completely filled and an air space is created between the fiberglass and the Tyvek® behind the metal sheeting? I ask because my walls are roughly 5 1/2” deep and obviously R13 is only 3 1/2” thick and R19 is 6 1/2” thick. If I go with R13 (cheaper) I end up with an air space. If I go with R19, I end up compressing it and losing r value anyway. Also, I have diagonal bracing in the corners which will also make it near impossible to tightly fill with fiberglass batts. I would love to go with the BIBs system but am waiting to see if it is within budget. If I can save considerable money insulating myself with batts I would most likely do so but need to be sure I am not causing problems down the road. Sorry for being so long winded and thank you very much for all your help and information.”

Mike the Pole Barn Guru responds: How Insulation Works

Fiberglass itself has little resistance to heat flow. The actual insulator is the air trapped in the tiny spaces between glass fibers. The tiny air voids slow conductive heat movement, while the glass fibers reduce radiant losses and impede air movement to block convective heat flow.

Don’t be fooled by so-called dead air spaces. Small air voids slow heat flow, but large voids don’t. A dead air space is one in which air does not move — once a gap gets larger than 3/4 inch, convection kicks in and overrides the insulating effect. Even though they contain air, uninsulated framing cavities have little or no R-value.

Making contact.

This understanding should govern the way batts are installed in the field. They should make good contact with wall and ceiling and nestle snugly against the sub-floor at the base within wall cavities. If the batts don’t touch the inside face of the drywall and the housewrap, convection coupled with air leakage will seriously undermine their thermal performance. Use only unfaced batts in exterior walls, because we’ve found inset stapled kraft-faced batts tend to create gaps between the insulation and the drywall. (Using unfaced batts also prevents the drywallers from complaining about the presence of stapling flanges on the surface of the framing.)

In other words, even though shoving batts into a wall girt cavity may seem like a no-brainer, doing it right takes some care. If a batt is simply jammed into place, its edges tend to drag along the sides of the girts on either side, which often prevents the rear corners of the batt from coming into contact with the exterior sheathing.

Moral of the Story

If your budget does not include closed cell spray foam insulation, then BIBs is a great solution and is effective.