Tag Archives: ceiling joists

Spray Foam, “Rat Guard” Trim Cutting, and Ceiling Support Spans

This Monday the Pole Barn Guru takes reader questions about spray foam in an attic space, cutting “rat guard” trim, and ceiling joists for a 9′ span between trusses.

DEAR POLE BARN GURU: I am in the process of completing my Hansen building and decided to spray foam the roof and gable ends above the walls. When they came in to do the work I found they had foamed over the ridge vent closing it off. When I questioned this they said that is what you do when foaming the roof and the attic becomes a conditioned space. R14 on the roof does not sound sufficient. My floor is wood 4 feet off the ground. Is this right? Where should I go from here? Thanks ED in MYRTLE BEACH

DEAR ED: Provided you are including your building’s attic area in your conditioned space (not insulating directly above ceiling) then closing off your vented ridge would be correct. I have not been able to find anything printed to verify adequacy of R-14 for roof insulation with closed cell spray foam in Climate Zone 3 (South Carolina), indeed 2009’s IECC (International Energy Conservation Code) used by South Carolina would seem to lead one to believe ceilings require a minimum of R-30 (Please see Table 402.1.1 https://codes.iccsafe.org/content/IECC2009PDF/chapter-4-residential-energy-efficiency).

When you have an opportunity, please send back photos of your building, they would be greatly appreciated.

 

DEAR POLE BARN GURU: Hello there, for the life of me I cannot figure out how to cut the “Rat Guard trim” at the outside corner! At a 45 degree angle!!!! Please help!!!!! DANIEL in VANDERGRIFT


DEAR DANIEL: In my humble opinion, base trim should be mandatory for steel sided building panels. It keeps creepy, crawly critters from entering your building via open steel panel high ribs.


Direct from Hansen Pole Buildings’ Construction Manual, here are your instructions: https://www.hansenpolebuildings.com/2016/12/cut-install-base-trim-corner/

 

DEAR POLE BARN GURU: I have a 9 foot span between my trusses on my pole building and want to install steel on my ceiling. Do I need to install 2×4 braces between the trusses for additional support? I am planning on blowing in some insulation once the ceiling is installed. JASON in ROCKFORD

DEAR JASON: While I have heard of builders installing ceiling steel liner panels on trusses spaced even 12 feet apart without any additional support, my personal comfort zone is five feet – meaning, in your case, I would be adding 2×4 ceiling joists between my trusses. Make sure your trusses are designed for at least a three psf (pounds per square foot) ceiling load (truss drawings will show this as BCDL – bottom chord dead load) otherwise they will not be adequate to support weight of a steel ceiling.

 

 

Stretching Stick Frame Construction

Post frame (pole building) construction is popular due to efficiencies of materials (ability to do more with less) and speed of construction.

Reader RAYMOND in BARLING is trying to find a way to make stick framing cheaper, he writes:

“24×64 pole barn in question. 4 pitch.  I am just comparing the cost of alternate designs.

Using 2×6 rafters with purlins across top for metal. Can I part from the standard 24 OC of rafters and expand to 30 OC (since more support from purlins)?

Furthermore, is it possible to use 30 OC studs all around, instead of poles (since more support from purlins on walls)

I would really appreciate your wisdom.

Thanks!!”

Mike the Pole Barn Guru says:

Let’s begin with, “since more support from purlins on walls”. Studs in stick framed walls will not resist wind loads perpendicular to a wall any better due to lateral support from purlins (actually girts) installed horizontally.

Your rafters are also going to be unable to support greater roof loads due to purlins being attached.

Building Codes have prescriptive requirements limiting what can and cannot be done with conventional (stud wall) framing, without having to have a fully engineered building. This would include studs and rafters being no greater than 24 inches on center. They also preclude wall heights of over 12 feet (you did not mention any heights however it should be kept in mind).

International Residential Code (IRC) Table R8702.4.1(1) provides rafter spans for common lumber species with a roof live load of 20 psf (this happens to be Code minimum whether snow is present or not). Being as you are in Arkansas, we will assume the minimum load as well as no ceiling being attached to rafters. With rafters 24 inches on center your rafters would need to be 2×8 #2 Southern Pine at a minimum. You would also need to provide ceiling joists or rafter ties to resist outward push of rafters on bearing walls. In order to get full value from rafters, ratio of rafter ties measured vertically above the top of stud walls to the height of roof ridge would need to be 1/7.5 or less. At a 4/12 slope ridge height would be 55.64″ meaning rafter ties could be located no more than 7-3/8″ above top of stud wall, so plan on then being at least 20 feet in length. A ridge board must also be provided as well as a collar tie, gusset plate or ridge strap (please refer to IRC R802.4.2).

Stud walls also mean you would need to make provisions for structural headers above any opening in any load bearing exterior wall. With post frame construction openings can be placed between columns in exterior walls, eliminating structural headers (this assumes trusses are placed aligned with wall columns with roof purlins on edge).

For stud wall construction, your concrete slab on grade will need to have an appropriately thickened edge in order to support weight of walls, or a continuous footing and foundation will need to be poured.

Ultimately post frame construction, not stick wall construction, is most probably going to be Raymond’s best route to go when considering investment and ease of construction.

Barndominium: One Story or Two?

Barndominium: One Floor or Two?

Welcome to an ongoing debate about whether it is more cost effective to build a one story or two story barndominium. Commonly I read people advising two stories is less expensive than a single story. Reader TODD in HENNING put me to work when he wrote:

“I’m curious why “Going to multiple stories will be more expensive than building the same amount of finished square footage on a single level”? Everywhere I read it says it’s cheaper to go up than out. For example wouldn’t there be more cost with bigger footprint of concrete, in-floor heating, roof trusses, and more steel on roof? Thanks.”


Mike the Pole Barn Guru writes:

It turns out Todd has requested a building quote from Hansen Pole Buildings, so I was able to work scenarios from his requested 40 foot wide by 48 foot long scenario. I arbitrarily merely doubled his building length when looking at a single story. It may have been more cost effective to have done this exercise by going greater in width and less in length (as one gets closer to square, there is less exterior wall surface to side, insulate and drywall).

Included were colored steel roofing and siding, commercial bookshelf wall girts to create a wall insulation cavity (https://www.hansenpolebuildings.com/2011/09/commercial-girts-what-are-they/), dripstop/condenstop under roof steel to minimize or eliminate condensation (https://www.hansenpolebuildings.com/2017/03/integral-condensation-control/), ceiling loaded energy heel trusses (https://www.hansenpolebuildings.com/2012/07/raised-heel-trusses/) with ceiling joists for sheetrock, 24 inch enclosed vented overhangs, vented ridge and one entry door. In the two story version I added floor trusses and a four foot wide set of stairs.

In order to maintain eight foot finished ceiling heights, two stories requires a 21 foot eave and single story 10 foot. Engineered plans and delivery were included.

I did not include materials for a bearing wall at the floor truss center. Features listed above ran roughly $6000 more to go two floors. Also, with the two floor version, you will lose 50 square feet of usable floor on each level due to stairs.

In this particular instance best overall buy could come down to what you pay for your slab and in-floor heating. Labor to erect a single story will be less expensive (I would predict at least a $3000 difference). Some other thoughts – two story has 1/2 as much attic insulation and 45% more wall insulation. Two story (excluding interior walls) has 30% more wall to drywall. This added exterior wall surface will likely result in more windows.

Personally, I own three multiple floor post frame buildings, these are my considerations:

Accessibility roughly 10% of all Americans will spend time in wheelchairs in their lifetimes. My wife is a paraplegic and we cannot get into one of her son’s homes because it is a split entry. Two of her other sons have built ramps for her, but they also have multi-story homes and it greatly limits areas she can have access to. In our own shouse (shop/house), we added an elevator after her injury (elevators are NOT cheap).

Stairs in general – you are probably much younger than my 62 years, going up and down stairs gets to be a chore as we age.

Heating and cooling – unless each floor is on their own system, one floor is always either too cool or too warm. I put one of my own buildings on two separate heat pumps for this very reason.

In conclusion, whether one story or two, go with what best fits your wants and needs and your property. Love what you build and it will result in a happy ending.

More Post Frame Ultimateness!

I am not even certain “ultimateness” is a word, if not, it should be!

In yesterday’s article I left you with a cliff hanger. Today I will talk you down. We disclosed one solve yesterday, today’s is even bigger.

“Can my building’s trusses support a ceiling?”

This lament gets answered over-and-over in my every Monday, “Ask the Pole Barn Guru” column. Traditionally pole barns were farm buildings. Rarely did anyone ever finish an interior, or live in one. Due to this, pole barn trusses are most often designed to support minimal weight from bottom chords. Sometimes this design loading is as little as ½ psf (pounds per square foot), but more often one psf.

Now one psf happens to be wonderful for things like minimal wiring and lighting. What happens when one wants to install a ceiling? Whoops.

Part of “The Ultimate Post Frame Building Experience™” includes us doing our best to assist clients in avoiding scenarios they will regret forever. An inability to support an initially unplanned-for ceiling would be way high on this list.

Most commonly ceilings are 5/8-inch thick gypsum wallboard (sheetrock). This is my ceiling material of choice, both for low investment outlay, as well as Type X providing some degree of fire resistance. Drywall is not light, roughly 2.3 psf. It also has to be supported by something other than widely spaced trusses. Ceiling joists (most often 2×6 every two feet) will add nearly a pound per square foot. Blown in insulation is relatively lightweight, even R-60 will add only 1.13 psf.

Hansen Pole Buildings has taken it upon ourselves to use a minimum of FIVE (5) psf for roof truss bottom chord design load on all spans up to and including 40 feet. This decision results in a capacity of 500 to 1000% more than most other post frame building kit providers, as well as post frame contractors!

Want to enjoy “The Ultimate Post Frame Building Experience™” yourself? Dial 1(866)200-9657 and speak with a Hansen Pole Buildings’ Designer today!

P.S. This has nothing to do with post frame buildings. For those who are counting (I know of at least one), this is blog article #1666 (oh, no three sixes)! Our youngest daughter happened to have attended a Jesuit high school, and she was so pleased when she got her first cell phone while there and her number’s last four digits were……6666! So Allison, this blog is dedicated to you!

How to Install Fiberglass Batt Insulation

How to Install Fiberglass Batt Insulation in a Post Frame Building Attic
There are times when I overlook things which seem obvious to me, but do not appear to be so to the innocent beginner doing their own construction work. This past week we were contacted by one of our new post frame building kit owners, who had hired a contractor to assemble his building. The contractor was apparently facing some challenges when it came to installing the unfaced fiberglass insulation batts in the attic space.

First step – unless your post frame building has trusses spaced every two feet, chances are good the ceiling joists must be installed between the truss bottom chords.

Exception (and not covered in this article) would be if your building is going to use steel liner panels for a ceiling and the trusses are spaced appropriately to be able to support the liner.

Step two is to install the ceiling material, which in most cases is going to be 5/8” sheetrock (although other materials such as OSB or plywood could be used). Do not install a vapor barrier between the ceiling materials and the ceiling framing.

Step three – lay down boards or plywood sheeting to help you be able to walk safely in the attic space.
When installing fiberglass insulation, observe all safety precautions. Fiberglass can release tiny fibers, which can be harmful if breathed into the lungs and which may irritate the skin. Wear protective gear.

The necessary R-value for the attic will depend upon the manufacturer and style of insulation chosen. Check with the manufacturer’s instructions on the packaging to determine how much insulation thickness is needed to achieve the desired R-value.

Once you’ve determined the amount and type of insulation needed, and the insulation has been purchased, begin staging the rolls in the attic. Place rolls around the perimeter of the attic for easier access during the installation.

Fourth – When laying insulation, it’s a common mistake to cover up the soffit vents. Soffits are part of the overall ventilation scheme, and covering them blocks essential air flow in the attic. With the widely spaced trusses typical of post frame construction, insulation baffles can be created by using rigid insulation boards to maintain a minimum two inch airflow above any insulation.

Fifth – Begin laying in the insulation, starting at an area furthest from the attic access.
When rolling the insulation, cut it to length using a utility knife.

When you reach the end of a line, pull the insulation back slightly, then place it on a joist so there is a solid surface to cut on. Using a straightedge as a guide, make your cut.
After making the first cut, use the remaining portion of the roll and work back in the other direction. When you reach the end of the roll, butt a new roll up to the cut piece and finish the run.

Once the perimeter is reached, cut the end of the roll to fit. Using this technique results in the best use of the insulation and reduces wasted material.
Lay the rows snugly together to prevent undesirable gaps or spacing.
When you run into an obstacle like a cross-brace or pipe, cut a notch in the insulation roll to fit around the obstacle, then continue with the run.

Areas around the perimeter of some attics can be rather tight and confining. Just keep rolling out the insulation, but don’t compress or squeeze it into tight spots, as this can decrease the insulation value.

Condensation Solutions, A Ceiling the Right Way, and Timing

Advice about condensation, ceilings done right, and the timing of questions

DEAR POLE BARN GURU: My deck roof is metal panels on 2×4 purlins, rafters are 2×6, like a pole barn. I am enclosing it, and need to stop the condensation. I spray foamed it with closed cell, but there is some condensation on the foam in a few places. It will be covered with drywall. Would a 6 mil plastic vapor barrier on the conditioned side work? MICHAEL in FRAZIER’S BOTTOM

DEAR MICHAEL: Provided you are able to reduce the moisture content within the building so as no vapor is being trapped between the vapor barrier and the foam, it should take care of the problem. In all reality, as long as you have no holes in the gypsum drywall, once it is painted you should have eliminated the problem of condensation against the insulation.

Now getting to the real problem – you have too much moisture in your building. If you did not place a well sealed vapor barrier under your concrete slab floor, you need to seal it. Walls also need a vapor barrier (without holes) on the conditioned side to prevent moisture from passing through.

 

DEAR POLE BARN GURU: I have a 40 x 80 pole barn with 8 foot truss spacing. I will be installing faced rolled insulation between each truss. What is the recommended ceiling product to install on the inside? Wood, metal, that will be lightweight and easy to install?? Thanks JEFF in SYCAMORE

DEAR JEFF: I see problems in your future….

Faced insulation is the absolute wrong product to use for insulating your ceiling. Any insulation placed at the truss bottom chord level should be unfaced. The best bet would be to blow insulation in above the finished ceiling.

In any case, you must adequately vent the attic space.

Now, on to the ceiling.

 

I am hopeful you have trusses designed with a minimum of a five psf (pounds per square foot) ceiling load, with 10 psf being even better. Confirm with your RDP (Registered Design Professional – architect or engineer) who designed your building, however 2×4 #2 ceiling joists at 24 inches on center between the bottom chords with joist hangers should adequately support a ceiling.

My choice of ceiling product?

5/8” Type X gypsum wallboard. It is affordable, weighs under three psf and provides fire resistance.

 

DEAR POLE BARN GURU: I’m putting up a building with a 3/12 pitch single sloped roof. radiant reflective polyethylene, vapor barrier insulation between the purlins and the metal roof sheathing. Probably rock wool batts under the 1-3″ draped barrier. Do you think the roof has to be vented, and how would this work? CHRIS in BROOKLINE

DEAR CHRIS: Yes, it would need to be vented and it is my feeling you are going about this entirely in the wrong direction. Your question is well timed, as I have just written an article on how to properly insulate between purlins, which will be posted soon. The basic gist is your best solution is to use closed cell spray foam applied directly to the underside of the roof steel.