Tag Archives: loft

Condensation Issues, Adding a Loft, and Metal Truss Load

This week the Pole Barn Guru discusses issues with condensation in a new building, advice for adding a loft, and achieving a roof load for prefabricated metal trusses.

DEAR POLE BARN GURU: Hello, I have a new construction pole barn that I recently had put up. The building is used to primarily house animals. When I had it put up I was told I would have to condensation issues with eave vents and a ridge vent that would extend the whole length of the building. The dripping really bothers me and I was wondering if there is a good option of putting a barrier of some sort on the bottom side of the purlins? My rafter spacing is 8ft. THOMAS in NEW SALEM

DEAR THOMAS: In most instances eave and ridge vents are inadequate alone to prevent condensation. Contractors who fail to include some sort of thermal break between roof framing and roof steel are doing a severe disservice, in my opinion. It is so easy to accomplish at time of construction with products such as a Reflective Radiant Barrier or Integral Condensation Control. There is not a good option for an underside of purlins vapor barrier, as it is nearly impossible to adequately seal it. Your only real solution, at this point, would be to use two inches of closed cell spray foam on underside of your roof steel.

 

DEAR POLE BARN GURU: My wife and I are building our post frame building ourselves. We’re building a loft living area on 1 end which I’m using 11.875 x 2.5 x 20′ long I-joist 16″ center.

My question is, My 6×8 posts are 8′ centers, can I attach a single 2x12x8′ between these posts and attach the I joist hangers to this to support the floor or will I need to double them like a header?

Thank you ALLAN in FORT ATKINSON

DEAR ALLAN: Any lofts, second or third floors being added to post frame buildings should only be done so under design of a Registered Professional Engineer – ideally whomever was Engineer of Record for your original sealed building plans. Rarely do concrete footings below building columns have adequate thickness or diameter to support additional loads being implied to columns. In most instances, beams for support of floor joists, I joists or prefabricated floor trusses will be limited in capacity by deflection, rather than ability to carry a given load. I can guarantee a single 2×12 is inadequate to support your I joists.

Your engineer will also determine proper number and size of fasteners to support beam to column attachments. At a minimum, with a 50 pound per square foot total floor load, columns every eight feet and a 20 foot span, each connection must support 4000 pounds of load.

Please, I implore you, do not attempt this floor design without proper engineering guidance – it could be lifesaving.

 

DEAR POLE BARN GURU: We are building a pole barn that is 20 by 32 with 8ft spacing. We are using steel trusses for this project, but our roof load for this county is 120lb per square ft., so how do I achieve this or how many trusses I would need to put in? Any help would help thank you. CHRIS in EMMETT

DEAR CHRIS: You should reach out to whomever provided your trusses to get an engineered repair. You should be able to have additional members welded onto what you have in order to meet required loads. On larger spans, this type of repair might not be possible.

 

 

Hardi-Plank Siding, Adding a Loft, and Blower Testing

Closing out the week with one more group of questions for the Pole Barn Guru. Today Mike answers questions about using Hardiplank on a pole building, the addition of a loft to an existing building, and performing a blower test for air leaks.

DEAR POLE BARN GURU: We are going to purchase an older house with wood siding, but might end up replacing the siding with Hardiplank in the near future. I want to build a pole building for a workshop soon. Is it possible to use Hardiplank instead of steel siding on the pole building so that the pole building and the house look similar? MICHAEL in BLACKLICK

DEAR MICHAEL: A post frame building’s beauty is it can have any type of roofing and/or siding desired. We have provided numerous buildings with James Hardie brand or other equivalent cement based sidings, so this would not be an issue. Unless there is some sort of prohibitive covenant, you might consider using steel siding on your home. It will be your most durable and cost effective design solution.

 

DEAR POLE BARN GURU: I have a 24×36 pole shop building and am considering building a 13×13 loft for storage on one corner of my shop. The girts are 2s6. My question is can I attach joist hangers directly to the girts for the flooring of the loft above or do I have to reinforce with 2×4 vertically spaced every 16 inches and hang the joist hangers from them? I plan on using 3/4 tongue and groove OSB flooring. CARLOS in CASTLE ROCK

DEAR CARLOS: No, you cannot hang your floor joists off from a wall girt.

You are doing a structural change to your shop – this requires a building permit. You should be consulting with an engineer who can examine your as built structure and determine what needs to be done to safely install a loft. For a space such as this your minimum design loading would be for light storage. Light storage requires a design live load of 125 psf (pounds per square foot). There is a good possibility your building’s wall columns do not have adequate area to support this type of load. Building stud walls is also probably not an answer – as your concrete slab is probably not thick enough to carry a wall with these loads.

Please do not just wing this – hiring an engineer is an inexpensive investment.

 

DEAR POLE BARN GURU: Hi Mike. I’m getting close to start interior finishing and have a question for you. I am trying to get the house as tight as I can so I’ve built a blower door so that I can evacuate the house and look for air leaks. Obviously with the ridge and soffit vents, there’s no chance to de-pressurize the house at all. I have been thinking about drywalling the ceiling so I can separate the main living space and the vented attic. I think I can get the drywall pretty well air sealed then I can check for major air leaks while the walls are still open.

Is what I’m thinking a bad idea? I can’t really think of any good reason why not to do it and there would be a couple of benefits.

Thanks for all the help you and the rest of the Hansen team have been in this whole process. LONNIE in COLORADO SPRINGS

DEAR LONNIE: You have been a pleasure to work with and our team has been waiting anxiously for progress photos from you (hopefully you have lots of them to share).

Your idea is actually not only excellent but is recommended by Green Building Advisor’s editor. Please share your test results as it will be interesting to see what you find and points where increased sealing was needed.

 

 

 

 

Lofty Barndominium Ambitions

Lofts and mezzanines (https://www.hansenpolebuildings.com/2020/03/a-mezzanine-for-your-barndominium/) are popular inclusions in barndominiums. Even though my lovely bride and I have a mezzanine in our South Dakota shouse, they are not often truly practical from an accessibility or economics stance.

Reader Devin in Porun writes:

“I’m designing and building a 42’x50′ pole barn home with 10′ exterior walls. Viewing the plans from the front entry on the long wall, the left half of the interior will be framed rooms and the right half will be a large open kitchen/dining/living room space. I want to have an open loft over the half of the building that has interior framing. I want to be able to stand in the loft for at least 3-5′ each side of center, roughly 6′ of head space when finished. What style/type of trusses do you recommend and at what pitch? Would you use the same trusses all the way across the house, or use different ones for each half with the same exterior pitch? I like the high ceilings over the open portion, but would like to minimize the ceiling height to avoid heating and cooling unnecessary space.  Thank you for your time!”


In order to have your greatest possible resale value, you should have any lofted space designed so as to be considered as habitable space. International Residential Code (IRC) Section R304.1 Minimum area. “Habitable rooms shall have a floor area of not less than 70 square feet. R304.2 Minimum dimensions. “Habitable rooms shall be not less than 7 feet in any horizontal dimensions. R304.3 Height effect on room area. “Portions of a room with a sloping ceiling measuring less than 5 feet or a furred ceiling measuring less than 7 feet from the finished floor to the finished ceiling shall not be considered as contributing to the minimum required habitable area for that room.” R305.1 Minimum height. “Habitable space, hallways and portions of basements containing these spaces shall have a ceiling height of not less than 7 feet.”

This space will also need to be serviced by stairs, causing you to lose roughly 50 square feet of floor space.

Now, on to trusses – most prefabricated wood truss manufacturers are limited to building and shipping trusses up to 12′ in height. Allowing for truss top chord thickness, on a 42 foot span your maximum roof slope will most often be roughly 6.25/12. You can order “bonus room” trusses for this lofted area, and should be able to get 7’2″ from top of truss bottom chord to bottom of ‘cross tie’ (allowing for thickness of 3/4″ OSB or plywood subflooring and drywall for ceiling to attain a seven foot finished ceiling) in center 10-11 feet, with a maximum room width of roughly 14 feet. These trusses will come along with a healthy cost premium due to larger members required to make this happen and extra shipping costs. In your open portion, you could utilize scissors trusses to reduce heating and cooling as much space, while still giving a spacious cathedral look.

When all is said and done, you might want to consider a more ‘standard’ and economical roof slope of say 4/12 – and add to your ground level footprint rather than trying to gain expensive space in a loft. Keep in mind, this loft space is going to be difficult to move large pieces of furniture (couches, beds, dressers, etc.) in and out of without damage to walls or items being moved and it will prove mobility challenging (or impossible) for a certain population percentage.

Adding a Second Floor to an Existing Pole Building

Adding a Second Floor in an Existing Pole Building

second floorMore than one pole (post frame) building owner has an idea of adding a second floor inside their existing building. Or, they plan a new post frame building with an idea of a future second floor being incorporated.

This apparently simple proposition has no simplicity involved.

Reader RYAN in HAMPSTEAD writes:

“Good morning,I have a 30×40 pole building, and I’m looking to add a partial second floor.  The posts are 8x8s, set at 8′ OC.  I’ve attached a layout for trusses that I received from another vendor, based on specs I provided.  The exact indoor measurement is about 29’11” outside to outside of the 8x8s (to the exterior sheeting).  The distance between the posts is about 28’6″.  So the joists should be field trimmable or around 29’8″ to carry from ledger to ledger.  I do not currently have the ledger/ribbon boards purchased or installed.

The trusses will be clear span, and the total floor space will be 30’x24′ with a cutout for a staircase.  Can you send a quote for this?  The shipping zip is 21074.

Thanks.”

Mike the Pole Barn Guru Writes:

Hansen Pole Buildings does not manufacture trusses, so we weren’t able to solve this portion of Ryan’s challenge. However, there are some considerations anyone should consider when looking towards a second floor being inserted in an existing post frame building.

Before moving forward, an EOR (Engineer of Record) should have originally designed your building. This person should be consulted with, as a second floor places a tremendous load upon wall columns and may overload footings (not to mention columns themselves), possibly causing columns to sink. Headers (also known as ledgers/ribbon boards) as well as attachment of floor trusses to them also need to be engineer designed. If somehow an engineer did not design your building, a competent one should be engaged to verify adequacy or design a repair.

Don’t be pennywise and pound foolish when it comes to structural changes involving a second floor, mezzanine or loft – lives you save may be your own, or those of a loved one!