Tag Archives: truss span

Insulation, Truss Spans, and Pit Material

Today’s Ask the Pole Barn Guru discusses reader questions about an option to layer insulation between purlins, the actual building width for 36′ trusses, and the recommendation against the use pit material when performing site prep.

DEAR POLE BARN GURU: Hi, I have the traditional roll type insulation with the white backing. My question is if I’m able to add more insulation between the purlins on top of the existing insulation for added r value and what type would you recommend if so? Thanks OWEN in VIVIAN

DEAR OWEN: Metal Building Insulation (MBI) is not my favorite design solution for post frame insulation (read more here: https://www.hansenpolebuildings.com/2011/11/metal-building-insulation/).

You can add more insulation to interior of what you have, without having to perforate white vinyl of you MBI. I would recommend adding unfaced Rockwool, as it is not affected by moisture and has a relatively high R value per inch of thickness compared to fiberglass or cellulose. Do not add another interior vapor barrier, as this would allow for moisture to become trapped between two vapor barriers.

 

DEAR POLE BARN GURU: You really are a wealth of knowledge.  I’ve been watching your Youtube videos as well, very helpful.

I’m intrigued by your pole barn kits, and I had just one more question about raised heel trusses:

It’s my understanding that post spans are actually building widths minus 3 inches.  So for a 36 foot building, the span between posts is 35’ 9”, correct?  If that’s the case, are raised heel truss lengths in this example also 35’ 9 to the edge of the post?  Or the full 36’, with the eave skirt board resting under the additional 1.5 inches of the bottom chord length?

Thanks again for your time!!! MATT in CHENEY

DEAR MATT: Our buildings (as are most Pacific Northwest Buildings) measure 36 feet from outside of column to outside of column. This allows for 12 sheets of steel plus the lap on the 12th piece (covering 36′ 1-1/2″ roughly) to be installed without having to rip the last steel panel lengthwise. Pressure preservative treated splash planks, headers, etc. will be applied to exterior faces of columns, giving a framed finished width of 36’3″.

 

DEAR POLE BARN GURU: Hi. In your building manual it notes not to use pit material on the building pad. If the site is leveled, I’m not sure what the function of any modified is or why no pit material in specific. We’ll be doing a slab at some point and common practice would be to put down some clean 3/4″ so if it’s beneficial to have stone on the building pad would it be more cost efficient to just put the clean stone down to start with? Thanks. KEVIN in WEST CALN

DEAR KEVIN: #1 reason to not use pit run is it is difficult to auger holes through.

#2 because it is round, it does not compact well

#3 It creates voids allowing for free flow of liquid water beneath slab

You do want to allow for two to six inches of clean sand or sandy gravel compacted immediately below your under slab vapor barrier.

 

Roof Insulation, a Riding Arena, and Closure Strips

Today’s Pole Barn Guru answers reader questions about insulating a roof to keep exposed trusses, the size limits for and equestrian riding arena, and whether or not to use closure strips between the gable (rake) trim and siding.

DEAR POLE BARN GURU: I have a 30×40 post frame building with cathedral style trusses. I really like the open look and don’t want to cover them with a ceiling. I want to insulate against the metal roof with vinyl faced blanket insulation to give a nice finished look. The roof currently has bubble wrap which I’m told I should remove so I don’t have two vapor barriers. Question is, if I remove the bubble wrap, is it ok to lay just blanket insulation between trusses or should I try to fill the 1.5″ space between purlins with foam board then blanket insulation over top of foam board. Or would filling the 1.5″ space with spray foam, then blanket over that? Thanks for any advice. BRIAN in LANDISVILLE

DEAR BRIAN: Only way to properly do as you propose is to remove bubble wrap, then have 2″ or more of closed cell spray foam insulation applied directly to underside of your steel roofing. Balance of insulation cavity can be filled with either more closed cell (best R value) or rock wool insulation (as it is impervious to moisture).

 

DEAR POLE BARN GURU: Need an open cover 150 L x 75 W x 13 H to function as a cover for an equestrian arena. Can a pole barn get this big? And if not what is the largest size we can go. JEFF in PINELLAS PARK

DEAR JEFF: While we have provided post frame riding arenas with up to 100 foot clearspans, in most geographical areas, wood truss fabricators are limited to building and shipping lengths up to 80 feet and overall truss heights of 12’.

Interior Clearspan Arena

For extended reading on riding arenas, please visit: https://www.hansenpolebuildings.com/2012/07/the-perfect-indoor-riding-arena/

 

DEAR POLE BARN GURU: Should I use closure strips between the gable trim (rake trim) and siding? The siding is tuff rib. STEVE in WARREN

DEAR STEVE: Standard form fitted closure strips are sized to only fit perfectly when applied at 90 degrees to length of steel panels. When going up rake trim, these closure no longer fit, however we have a perfect solution Emseal! https://www.hansenpolebuildings.com/2016/03/emseal-self-expanding-sealant-tape-closures/
To acquire, please reach out to Materials@HansenPoleBuildings.com along with lineal footage required and ship to zip code.

 

Convert to Residence, Insulation, and Truss Spans

Today’s Pole Barn Guru addresses reader questions about building upgrades to convert to a residential use, how to best insulate a monitor style building, and the possibility of trusses spanning 40′ to eliminate interior posts in a shop/storage building.

DEAR POLE BARN GURU: We bought a pole barn with no insulation, just studs and metal siding. We added faced batting insulation. But now we are thinking of making it a residential building. Do we need to remove the siding and put OSB and a vapor barrier house wrap on it? How do we refit this for a residence? KIMBERLY in COLUMBUS

DEAR KIMBERLY: No you do not have to add OSB and a Weather Resistant Barrier to your exterior walls.
Most pole barns are not designed to support wind and snow loads to extents required for residential applications – you should invest in services of a Registered Professional Engineer who can do a physical examination of your pole barn to determine structural adequacy and provide solutions for upgrades to make it safe for you to live in.

 

DEAR POLE BARN GURU: This has been covered 1 million times but I wanted to reach out directly! I’m in North Carolina. I have a 30×50 pole barn with a 20×50 lean to off both sides. The lean tos are accessible from inside the main shop. So imagine one large open space. Lean to walls are 10’ rising to 14’. Main shop is 16’ rising to about 22’ at the peak. I have bubble wrap foil under the metal on the roof. Open 2×6 ceiling. 2×6 walls with nothing on them but metal. I will add interior wall coverings probably in the form of 7/16 osb. Concrete has vapor barrier.

Buildings with loftsNow, I’ve been told to do closed cell insulation on my walls 1” thick. I wanted an opinion on whether to go every inch of the walls top to bottom all the way to the roof? Would I benefit from the insulation at all by just going to the 10’ mark (my lowest wall height) because that’s as high as my interior osb is going anyway. I guess what I am asking is it any benefit to insulate closed cell up to 10’ mark from the floor and then just bubble foil the main shop above 10’ to give a finished look? THOMAS in PLEASANT HILL

DEAR THOMAS: Unless you are planning on some degree of climate control in your building, there would be no real reason to make an investment into closed cell spray foam. If controlling interior temperature is a goal, then spend your money on insulation in your roof/ceiling where over ¾ of your heat loss/gain is coming from, before spending money on wall insulation.

 

DEAR POLE BARN GURU: We are looking to build a 40×90 pole barn, with 1/3rd being used for storage and 2/3rds for a vehicle maintenance. Both will be heated and storage cooled. Concrete floor, shingled roof, insulated, vertical metal siding, no windows, 5 overhead doors on the same side. Can you span the trusses from wall to wall and provide the above with no center columns? Thank you, ROD in CLEVELAND

DEAR ROD: Prefabricated metal connector plated wood trusses allow for some tremendous clearspan opportunities. We provide fully engineered post frame buildings with clearspans up to (and in some instances beyond) 80 feet. Your 40 foot width can quite easily be accommodated without any interior columns. One of our Building Designers will be reaching out to you Monday to further discuss your building needs.

 

Span, Vapor Barriers, and Planning a Pole Barn

This week the Pole Barn Guru answers reader questions about the widest span a post frame building can be built, vapor barrier on a roof only structure, and the proper steps for planning a pole barn.

DEAR POLE BARN GURU: How wide can you span? And approx cost per sq ft for an erected shell, (no floor Hvac or electric. 100’x110′ bldg.. JOHN in LEWES

Arena Interior

DEAR JOHN: While we have quoted fully engineered post frame buildings up to 140′ clearspan with prefabricated wood trusses, 100′ is widest we have provided. Due to possible shipping and fabrication challenges, these spans are not available in all markets and further research would need to be done based upon your location and load conditions. A Hansen Pole Buildings’ Designer will be reaching out to you for further discussion.

 

DEAR POLE BARN GURU: Is a vapor barrier needed for metal roof if it is open, no walls? CRAIG.

DEAR CRAIG: While Building Codes do not require one – if it is absent you are likely to have periods (especially in Spring and Fall) where it will rain inside of your building. Most people erect new buildings with an idea of protecting contents from climactic conditions such as rain, so this result may be less than desirable.

I would recommend you order roof steel with a factory applied Integral Condensation Control (ICC). ICC is available with trade names such as Dripstop and Condenstop.

 

DEAR POLE BARN GURU: My wife and I may be obtaining property in western Oregon and have been kicking the idea around building such a structure. We really don’t know where to start and what this all entails. We really like the idea of having a simple open concept with a decent size shop attached so all our vehicles and RV can be stored inside. I was just really hoping to get a starting point and go from there. Thank you for your time! COLE in OREGON

DEAR COLE: Thank you for reaching out to us. Links in this article should assist you in getting off to a start in the right direction: https://www.hansenpolebuildings.com/2019/10/show-me-your-barndominium-plans-please/