Tag Archives: slab

Suitable Base, Insulation, and Building in Flood Zone

This week the Pole Barn Guru addresses questions about whether or not a base will be suitable for a slab, if a person HAS to insulate if they intend to heat the structure, and building 13′ above grade foundation in a flood zone.

DEAR POLE BARN GURU: Good morning, I’m getting ready to have a slab poured in my 30’x30′ pole barn, the slab will be 7 inches thick (was meant to be 6 but I failed to bring the base material up high enough) of 4000psi, with fiber mesh along with wire mesh. The pad site is level and compacted asphalt millings (compacted by a 14 ton vibrating roller). The base material I was advised to use is a “clean fill”, that is mined from below ground from a local quarry, its best described as similar to a baseball infield dirt. The base is approximately five inches thick. I personally put the base down, spraying it with water and compacting with a vibrating plate compacter as I went. My main question is based upon your knowledge, is it your opinion that this will provide a suitable base for the slab? I appreciate any input you may have. Thank you and thanks for a great site! ADAM in CLARKSBURG

DEAR ADAM: Thank you for your kind words. Concrete makes for very expensive fill and unless you are planning on some very heavy equipment being placed on your slab, more than four inches is probably unnecessary. As to your base, without having had a Geotechnical Engineer do a site analysis, it is impossible for me to confirm adequacy of your fill as described. Your “clean fill”, as described, has me somewhat concerned as baseball infield dirt is fairly fine and could prove a challenge in obtaining adequate compaction. Normally I would expect to see 3/4″ minus or similar crushed stone.

 

DEAR POLE BARN GURU: If an individual builds a pole barn that he intends to fully heat does he HAVE to insulate it? Can’t find a definitive answer in the IBC or IECC. BOB in CROWN POINT

DEAR BOB: If your heating source requires a permit, your Building Department is going to expect appropriate insulation. From a practicality standpoint, it would be prudent to insulate.

 

DEAR POLE BARN GURU: Hello, Our property is in a flood zone. We would need to build on a 13 foot above grade elevated foundation. Any ideas if this is feasible with a pole barn kit? Thank you ED in BOLIVIA

DEAR ED: Fully engineered post frame buildings are very adaptable to flood zones, they make excellent for excellent stilt houses. Our engineers will need some specifics on your property’s flood specifics. https://www.hansenpolebuildings.com/2017/09/stilt-houses/

Site Prep, Brackets on Slab, and Treated Lumber

This Wednesday the Pole Barn Guru answers reader questions about site preparation and underground obstructions, a recommendation for building with wet set brackets on slab, and whether or not Hansen Buildings uses lumber treated for in-ground use– UC-4B.

DEAR POLE BARN GURU: We recently started the ground work for our future 48×72 pole building. Half way through excavation the crew hit a solid slab of rock at the corner of our building site. It appears to be Pennsylvania blue stone and the space that it takes up includes a majority of the back and left side where the building walls would sit. We were able to achieve a level pad but we are extremely concerned that now we won’t be able to build on this site. This is the only place on our property that has room for this build and we are very worried that we won’t be able to set poles in the ground do to the size of this solid slab. What are our options, if any? KIMBERLY in PENNSYLVANIA

DEAR KIMBERLY: This brought back childhood memories of my Dad taking me out on a Saturday to a site above Hayden Lake, Idaho where he and my uncles were going to be framing a custom home. Site had been cleared, and there were all sorts of roughly inch and one-half diameter holes drilled into solid rock – they had to blast in order to get a foundation in!

You do have many options, however blasting can be (I have found) quite affordable. Many years ago we built a horse stall barn near Benton City, Washington. This building had a total of 84 columns and was on a rock shelf. Powder monkey came out and blasted all of them for a couple of hundred dollar bills!

There are other choices – you can rent a “ram hoe” attachment for a skid steer or backhoe (this would probably be my pick). Read more here: https://www.hansenpolebuildings.com/2016/12/attacking-pole-barn-rocks-holes/

Or, a jackhammer – I would not suggest this option for more than just a hole or two.

 

DEAR POLE BARN GURU: I am in the planning stages for a pole barn build. The building will be 50 ft wide by 40 ft deep by 16 ft high at the eaves, posts spaced at 10 ft centers. This will go on a concrete pad and I am looking into using Sturdi-Wall Plus wet set brackets. My question is in regard to the height of the posts (roughly 16 ft) and the bending moment loads (wind loads) on the side of the building. Have you designed/installed posts with this height or higher before? If so, is there a place where I can point the planning officials to that shows the calcs and what not so they can make a decision as to whether or not this type of application with my situation will work or not?

I appreciate your help! MICHAEL in UPTON

DEAR MICHAEL: Thank you for reaching out to us. We have provided fully engineered post frame buildings using these very same brackets and eave heights of 24′. Your real solution is to have your building plans done by a Registered Professional Engineer who can provide verifying calculations for all components and connections.

 

DEAR POLE BARN GURU: I have a question about the structure of your pole barns. Do you use treated lumber or non treatmented lumber? I am asking about the post that go in the ground AND the boards that touch the metal roof. I worry about the wood rotting or bugs getting in it. KRISTEN in BAY MINETTE

DEAR KRISTEN: Any roof supporting structural columns are pressure preservative treated to UC-4B per International Building Code requirements. This is a greater level of pressure treatment than you can usually find at big box stores or local lumberyards. Any other lumber used in ground contact will be treated to UC-4A and tags will reflect ‘ground contact’. Lumber in contact with steel roofing (roof purlins) are not exposed to the weather, would not typically be pressure preservative treated. We do always recommend a condensation control be used between roof steel and roof framing. The easiest, from an application standpoint, would be a factory applied to roof steel Integral Condensation Control (DripStop or CondenStop). Other alternatives would be a Radiant Reflective Barrier (we can provide this in six foot width rolls with an adhesive pull strip attached for ease of joining rolls together) or to use two inches of closed cell spray foam.

 

Wall Framing, a Sloped Build Site, and Engineering for Slab

Continuing the week with more Pole Barn Guru, Mike discusses spacing of framing for wall steel, how to prepare a sloped build site, and if Hansen can provide engineering for slab on grade in Colorado.

DEAR POLE BARN GURU: If you have 2×6’s for walls in pole building that are spaced 16 inches apart, and want to put metal siding up, would I use like a wood girts every 2 feet apart in order to hang the metal siding up and down? JOSEPH

DEAR JOSEPH: I will read between lines and guess you have built stud walls between building columns. If this is your situation then you will need to have horizontal girts added in order to attach wall steel vertically. You should refer to your engineered building plans for size, spacing and attachment of these girts, as your engineer is most likely counting on your steel skin to provide needed wall diaphragm strength.

 

DEAR POLE BARN GURU: The area I want to put a pole barn has a severe slope of 6′ from one end to the other. Should I excavate this ground to make it level or build a masonry wall on low end to bring level? If I excavate I’m concerned about moisture getting into building from the high end. If I build a wall, I’m concerned about the pressure on the wall that could eventually fail or the back fill settling under the concrete floor causing cracks. Thanks so much for your help. DAN in EDDYVILLE

DEAR DAN: Well you have lots of possibilities. Given what you have provided, I would be inclined to cut roughly four feet from your high side (making your cut back another eight to 10 feet from your building) and then fill on low side, with a retaining wall eight to 10 feet beyond your building. This way you can slope grade away from building in both directions. Walls will be far enough away from building to not affect it. If you have clay in your soil, make sure to remove at least top 18-24 inches where building will be located and replace it with good, properly compacted fill.

 

DEAR POLE BARN GURU: Does your company handle all the engineering required for an interior monolithic slab? We are very interested in a pole barn home (about 1300 SQ ft) but are running into a lot of issues with the interior slab. We will be building in Fremont County, CO at 9400’ elevation. Frost heave is a huge concern. JEFF in FREMONT County

DEAR JEFF: We would need to have an engineered soil’s report as well as to know your intentions for heating (always heated or not always heated). With this information we would provide engineering for your slab on grade.

 

 

A Residential Pole Barn, Missing Lumber, and Building on Existing Slab

Today the Pole Barn Guru answers questions about plans for a residential pole barn, lumber going missing, and to building an existing slab.

DEAR POLE BARN GURU: Hello, I’m looking to build a residential pole barn. I would need enough space for 3 bedroom 2 bath. How big of a pole barn would I need? CULLEN in ROCHESTER

DEAR CULLEN: It depends upon what sort of spaces you want to live in. I grew up in a home which was just as you describe and only 960 square feet. Conversely, right now I live in a home which has one bedroom, 1-1/2 baths and has 2400 square feet of living space.

I encourage you to go to lots of open houses, take your tape measure and a notebook. When you find rooms feeling comfortable to you, measure them. Consider spaces you need to create for your lifestyle. Don’t short yourself when it comes to closets, storage spaces, etc. Do you need a family room and a living room? Maybe just a great room?

Once you get rough sizes and needed spaces figured out, fit them together like a jigsaw puzzle to make most efficient use of space. Try to minimize hallways as well as travel distances – think about how many trips get made to a laundry room. How many footsteps are taken during those trips between opposite house ends? Place those utility areas where they are most convenient.

When finished, draw a box around your creation and this will give you space you need.

DEAR POLE BARN GURU: What grade lumber should we use for the roof purlins on a pole barn building? It appears we have run very short on our project (I think somebody made off with a bunch during the night)! Prime, #1, #2, etc.???? Building in Northeast Pennsylvania, 4ft OC trusses, purlins spaced 2ft OC. JOEL in DUPONT

DEAR JOEL: Sadly jobsites suffer from a high incidence of pilferage. When I was a post frame building contractor, we did a big project in Northern Idaho. We’d lose nearly a unit of 7/16” OSB every night until we had a fence put up around our materials! Apparently it was an overly friendly neighborhood where everyone shared without asking.

To find out appropriate grade for roof purlins you are short, refer to your engineer sealed plans provided with your building kit package. They will specify size, grade and spacing.

DEAR POLE BARN GURU: I have an existing block and slab detached garage. It is old and well built but smaller than I want and the overhead doors are on the wrong face for my purpose. I would like to replace this 24×24 structure with a 36×60 pole barn. Removing that much concrete and then replacing it will add a good bit of cost and time to the project. Would it be possible to use the existing slab and foundation for the posts that would be on it using brackets and the rest of the posts set more traditionally in concrete or using piers and wet set brackets? ROB in ANNAPOLIS

DEAR ROB: Provided your existing concrete has adequacy to support your new building, it would be possible to use dry set anchors to mount columns in those areas. If any doubts about adequacy, you should consult with a RDP (Registered Design Professional – architect or engineer) who can evaluate your situation in person. For cost and ease of construction, I would typically recommend balance of columns being placed in augered holes.

 

Installing Insulation, Properly Treated Posts, and a Slab Solution

The Pole Barn Guru helps with installing insulation in wet seasons, properly treated posts, as well as a solution to embedded posts when bedrock is present.

DEAR POLE BARN GURU: Hello. I am ready to install the insulation and metal on our pole building’s roof. I remember reading how it is important to install the insulation and roof when things are dry as to keep the insulation dry. We have recently moved into a rather wet early fall, and dry weekend days have seemed very illusive.

Do you have any expert ideas or advice that you may be able to offer us? I appreciate all of the very useful help and insight you’ve provided us numerous times already! BRAD in MOUNT VERNON

DEAR BRAD: You want to avoid trapping water between Radiant Reflective Barrier and roof steel, as it can lead to premature deterioration of roof steel.

A helpful hint – in rainy weather only place one run of barrier and if upward surface gets wet, towel dry it and immediately install steel roofing to cover.


Just one reason I now recommend using roof steel with an Integral Condensation Control: http://www.hansenpolebuildings.com/2017/03/integral-condensation-control/.

DEAR POLE BARN GURU: Opinion in using 9” x 25’ class #3 pressure treated utility poles as columns or posts? I have come across a grip of poles in coastal pacific Mexico. Pondering the use of them as my columns/posts in cabin and deck style construction. Their structural and dimensional properties suited for use as such? Thank you. CARL in ZIHUATANEJO

CARL: I personally would not want to use them as level of pressure preservative treating (as well as chemicals used) could very well be iffy at best, toxic at worst. Read more about utility poles in post frame construction here: http://www.hansenpolebuildings.com/2012/11/used-utility-poles/.

 

DEAR POLE BARN GURU: 26’ x 42’ pole barn planned. We hit rock 6” down. Builder now wants to consider option of to pour the 4” slab first and use post saddles to anchor the posts on top of the slab. He says “This is a good option and results in longer life of the treated posts. Included in this option is additional bracing on each post” Is this really a viable option???

Help! Thank you. VICTORIA in FAIRVIEW

DEAR VICTORIA: Unless your builder can provide engineer sealed plans for your building including his “solution” fire him now because he has no clue.

Why do I say this? A four inch thick concrete slab only will provide inadequate to mount a building to.

In photo of correct bracket below, concrete would need to be deep enough to have rebar entirely embedded in concrete:

 

While a properly pressure preservative treated column will last longer than any of us will be alive to witness, of course if it does not touch ground it eliminates potential of any decay due to ground issues.

Read more here: http://www.hansenpolebuildings.com/2016/12/attacking-pole-barn-rocks-holes/.

 

Proper Foundation and Slab, Two-Story Buildings, and Door Parts

Proper Foundation and Slab, Two-Story Buildings, and Door Parts

DEAR POLE BARN GURU: Dear Sir, I read the details of pouring a concrete slab after building the barn. I live in Montana with some pretty cold winters. If I were laying a slab for a conventional stick built structure i would be required to dig footings 48” deep all around the perimeter. What should I do if I am building a pole barn? While I may supply low level background heat I would like a construction that does not require it to resist Montana winters.
Regards, DEREK in KALISPELL

DEAR DEREK: Regardless of the type of construction used, the success or lack thereof for your slab is going to come from what you do underneath it, as well as grading the site properly to keep water from pooling below it.

Follow along first by reading my series of articles devoted to site preparation which begins with: https://www.hansenpolebuildings.com/2011/11/site-preparation/.

You will want to have your building site graded so as there is a 5% slope away from the building, when completed.

Now the fun part – protecting your building itself. I’ve become an advocate for Frost-Protected Shallow Foundations. Here are a couple of articles which should get you heading in the right direction: https://www.hansenpolebuildings.com/2016/11/frost-protected-shallow-foundations/

and https://www.hansenpolebuildings.com/2017/09/post-frame-frost-walls/.

DEAR POLE BARN GURU: Do you offer 30 x 40 2 story apartment/garages?? ROB in ALPINE

About Hansen BuildingsDEAR ROB: We offer any dimension of footprint you desire, not just 30 foot width by 40 feet long and would encourage you to look at what works best for you in an internal layout, then create the exterior dimensions which best fit your interior needs. Two and even three full or partial stories can easily be done with post frame construction and if your zoning allows the overall height and you are willing to add sprinklers, you could go four stories.

Your mixed use will probably result in having to at least one-hour fire separate the apartment from the garage. This could include having to protect the stairs, if they are interior, as well as to provide clear protection all the way to the outside world. A discussion with your local planning and zoning friends could provide you with added insights.

DEAR POLE BARN GURU: Do you have available, either metal or wood, a barn door and hardware for an opening 8′ high and 5′ wide, to be placed within a screen porch (the entrance to the garage)? TRISH in WIMBERLEY

DEAR TRISH: Thank you for your interest. Due to shipping challenges, we now only provide barn doors along with the investment into a complete post frame building kit. You might try contacting the ProDesk at your local The Home Depot®.

 

 

 


A Door Guide with a Roller, When to Pour Concrete, and Bedrock Anchors!

DEAR POLE BARN GURU: I am looking for a bottom guide for a sliding barn door. I was hoping to get a guide with a roller vs. just a roller. I noticed some guides trap the roller in a channel on the bottom of the door. I would like to know if you have that and where to purchase in Lower west Michigan.

Thanks, GERARD in PLAINWELL

DEAR GERARD: I have found the very best sliding door guide systems do not use bottom rollers at all. Known as “stay rollers” the bottom rollers tend to be problematic, especially in tough climates or when large animals are present.

Figure 27-6

The most secure and effective method utilizes a bottom girt for the door which is most typically a galvanized steel channel 1-1/2” x 3-1/2” (think of a steel stud) with a slot in the 1-1/2” face towards the ground. A galvanized steel “L” is mounted via brackets to the wall in the direction the door slides open. The upward leg of the L engages with the slot in the bottom of the lowest sliding door girt.

This design solution provides stability for the bottom of the door, preventing it from coming away from the building, or slapping against the ribs of the steel as it opens. Hansen Pole Buildings does not provide sliding door components other than with the investment into a complete post frame building package. You might try the ProDesk at your local The Home Depot®, as they should be able to order the parts in without you having to pay an onerous amount of freight.

 

DEAR POLE BARN GURU: Would I have the concrete slab poured before the building is erected or pour the slab after the poles are installed? Thanks. JOHN in REMER

DEAR JOHN: One of the beauties of post frame construction is the ability to be able to pour your new building’s concrete slab on grade at any time after the columns are placed in the ground. My personal preference is to at least wait until the roof is on – as it provides greater protection from sudden unexpected rainstorms as well as sun. The best time to pour (in most situations) is after the building shell is fully completed. Premix concrete trucks do seem to have an affinity for running into building columns which are not part of a wall.

 

DEAR POLE BARN GURU: Dealing with a site that is less than 20 inches above bedrock and is a wet environment. Frost line construction standards normally require 48 inch depth. What foundation, site prep concerns are relevant. Hoping for a barn about 30 x 40 x 12 RON in ONTARIO

Footing DetailDEAR RON: Code specifies the depth of foundations (in this case your columns) must be either below the frost line, or to solid bedrock. You will want to discuss your particular site challenges with the registered design professional (RDP – architect or engineer) who provides the sealed plans for your building. Our engineers will often solve this anchorage problem by having you drill holes into the bedrock to epoxy in rebar pins which will be embedded into the columns, then backfilling the holes with concrete. To minimize potential frost heave issues, you will want to read my articles on site preparation (use the search bar at the upper right of this page) – as you will want to remove any soils which could contribute to heaving.