Tag Archives: UC-4B

Minimizing Excavation in Post Frame Buildings Part II

Minimizing Excavation In Combination With Post-Frame Frost Protected Shallow Foundations Part II

In our last thrilling episode Snidely Whiplash had tied our fair damsel in distress, Nell Fenwick, to railroad tracks.

Oops – railroad engineers are not what most of you were expecting!

Continuing with a simplified solution response to reader DAVID’s ideas regarding site preparation and Shallow Frost Protected Foundations (SFPF) for post frame buildings.

Dear David ~

Thank you for your patience. As you may know from reading this column, I tend to research everything to best of my abilities prior to writing an article or responding to questions. Areas of site preparation and concrete flatwork are ones where I have a more limited amount of personal experience, so I have been doing a plethora of reading and contacting (and discussing) with concrete experts. I also am not married to a position, as better information becomes available, I take advantage of it.

Article you reference in (1) has been updated since you last perused it. Even though many RDP (Registered Design Professionals – architects and engineers) specify sand over under slab vapor barriers, I have now become a “no sand above vapor barrier” school convert.

To follow, a summation of my thoughts in regards to this subject, with top of slab being fixed 3-1/2” above grade.

(a) Excavate entire site to remove organic materials. Area to be excavated should be a minimum of three feet outside of actual building foot print. Depth of excavation below zero point (grade) should allow for any concrete thickness greater than a nominal four inches (3-1/2″ actual), two inches of insulation board (if desired), two to six inches of sand or sandy gravel and six to 12 inches of sub base. Assuming a nominal four inch slab, total depth of excavation should be 16 inches if doing a FPSF.

(b) Auger holes for columns, stand columns in augered holes and backfill with concrete per engineered plans.

(c) Install splash plank/skirt board, with board bottom even with grade (zero). There would be no reason to increase dimension to greater than 2×8, as vertical insulation boards prevent any concrete in a slab thickness greater than a nominal four inches to “leak” to outside world.

Side bar – 2×10 or 2×12 pressure preservative treated material will be available, however many times only via special order. If any portion were to be entirely embedded below grade, then appropriate treatment level would more probably be UC-4B – as UC-4A treatment levels are strictly for ground contact.

(d) Place vertical and horizontal insulation boards for FPSF – backfilling with sand or sandy gravel sufficiently to hold vertical insulation boards in place.

(e) Place sub-base, then base material, compacting in lifts.

(f) Place 15mil vapor barrier (make sure to run it up insides of splash planks); Under slab insulation (as desired); pex (https://www.hansenpolebuildings.com/2016/08/pex-tubing/), rebar and/or mesh, and then pour the slab.

This minimizes excavation by eliminating need for a trench.

 

Properly Treated Posts, Hillside Locations, and a Post Frame Option

This week the Pole Barn Guru answers questions about properly treated posts, building on hillside locations, and an option to build with post frame.

DEAR POLE BARN GURU: According to most of the answers on the Internet, if I bury the posts for my deck they will rot away and the whole thing will come crashing down 10 or so years. What proprietary space-age technology are you using in your pole barns that deck builders don’t know about?
(yes this is a bit tongue-in-cheek) MM in MILTON

DEAR MM: How about we start with over 50% of all builders did not graduate from high school? The great majority of deck builders call in, text or email the lumber list for the next deck to their supplier of choice. I worked in or owned my own lumber yards for years and never, ever can I recall a builder specifying a level of treatment when they ordered pressure preservative treated wood.

Builder says treated, and he gets treated….probably not adequate for most applications. Any lumber placed structurally into the ground should be treated to a minimum UC-4B retention. I wrote this article for Rural Builder magazine, so it is directed specifically towards builders and suppliers, however it should make my point: https://www.hansenpolebuildings.com/2014/05/building-code-3/.

 

DEAR POLE BARN GURU: I have a hillside location and am looking for information on pole housing in California and their seismic ratings? ROBIN in SAN DIMAS

DEAR ROBIN: San Dimas – the town Bill and Ted made famous! Post frame (pole) buildings perform admirably on hillsides, as they can be attached to partial foundations (https://www.hansenpolebuildings.com/2012/02/grade-change/) or built on stilts (https://www.hansenpolebuildings.com/2017/09/stilt-houses/) to compensate for grade changes.

As far as seismic design, structures are affected by earthquake in relationship to the weight of the structure. The lighter the structure, the more resistant it is to tremors! Here is a little earthquake reading: https://www.hansenpolebuildings.com/2015/10/a-whole-lotta-shakin-going-on/ and https://www.hansenpolebuildings.com/2016/05/earthquake-resistant-post-frame-construction/.

 

DEAR POLE BARN GURU: I am in the engineering phase of our forever home in Minnetonka. I have an architect drafting my designs, and am now working with structural engineers to figure out the best way to construct it. My original plans show double stud 2×4 walls (for super insulation), and our ceiling heights are on the tall side.

An option we are considering is getting the house pole framed for the interior stud wall, and then site framing the exterior stud wall, in order to create the cavity for super insulating. I also plan to use an interior ledger system for the floor joists.

Let me know if you think this is a possibility. I can send you our current drawings for you to look at. There are obviously a lot more details to sift through than what I’ve covered in this email.

Let me know! Thanks! SONJA in MINNETONKA

DEAR SONJA: One of the great features about investing in a post frame building kit package (at least from Hansen Pole Buildings) is it includes the engineered structural plans for your new home – no need to pay an expensive structural engineer!

Installing Drywall on CeilingThere is probably a much easier way to achieve your super insulated walls – using post frame construction and ‘commercial’ bookshelf style girts, you can create a deep wall insulation cavity for one or a combination of the following: unfaced fiberglass or rock wool (best since it is not effected by moisture) batts; BIBs (https://www.hansenpolebuildings.com/2011/11/bibs/); and/or closed cell spray foam. Between the inside of the framing and the wallboard, use high R insulation board, which creates a thermal break between and wall framing and the interior conditioned space.

We’d be pleased to assist you in your project.

 

 

 

 

Splashwood

Splashwood™

Reader MIKE in ORLANDO writes:

“Dear Pole Barn Guru,

I bought a 38×42 Pole Barn kit from a reputable supplier. The posts are 8″ x 8″ – but do not have the AWPA markings that you describe in your Blog. These posts have a tag stapled to the end that says “SPLASHWOOD, Saltwater Splash Use Only, .80 PCF, Chromated Copper Arsenate (CCA-C), Southern Wood Preserving, Inc,.” and a paragraph of cautions and Consumer Information. I tried to look up this info to see if these posts are AWPA UC4B equivalent but could not find any info on-line.
Are these post acceptable for my Pole Barn construction?
Thanks.”

Mike the Pole Barn Guru writes:

Splashwood™ happens to be a registered trademark and brand of Great Southern Wood Preserving, Inc., and was filed December 30, 2004. Great Southern Wood Preserving, Inc., is based in Abbeville, Alabama and was founded in 1970. It has 15 plants located in Alabama, Arkansas, Florida, Georgia, Mississippi, Missouri, Louisiana, Maryland, Virginia, Pennsylvania and Texas with annual revenue of a billion U.S. Dollars.

Pressure-treated wood is treated to various retention levels which are intended to protect the wood for particular applications. Retention levels indicate the amount of preservative retained in the wood in a specific assay zone. In North America, retention is expressed in pounds per cubic foot (pcf).

Retention levels or treating quality procedures are marked on pressure treated wood. The AWPA (American Wood-Preservers’ Association) outlines retention levels required for various applications.

Retention varies with depth in the wood, so preservative penetration also affects wood longevity. In species with large amounts of sapwood, such as southern and red pine, the preservative must penetrate 2.5 inches or 85% of the sapwood to meet standards.  In western species which are predominately heartwood, the wood is incised to ensure a treated shell, and any cut surfaces should be field-treated with a preservative containing at least 2% copper (read more about cut ends of treated lumber here: https://www.hansenpolebuildings.com/2014/09/pressure-treated-lumber-2/).

To meet the Code required standard of UC-4B for structural timbers, takes a retention of 0.60 pcf with CCA. The pressure treatment of your columns exceeds the minimum requirements.

 

Concerns of a Post Frame Building Kit Shopper

Hopefully most, if not all, of my loyal readers are those who have concerns when it comes to investing in a new post frame building (I do know some of you just enjoy my slightly skewed sense of humor, or find my writings otherwise entertaining). For those of you who are avid kit shoppers, I try to give honest advice to any question posed to me.

Reader TRAVIS writes:

“Hello, I’m shopping around potential kit purchases and have a few questions. 

First off I’m planning to finish the interior, are the long spans between trusses you design able to handle the dead weight of drywall ceilings? 

One of my main concerns is column rot as my area is fairly wet. What type of treatment is used on the columns, where do you source them from, and do you ever recommend concrete permacolumns? 

Is it possible to use half scissor trusses and half regular to gain extra height in only certain areas? 

Thank you any help is appreciated.”

Mike the Pole Barn Guru gives advice:

Yes, we are able to design roof systems to support virtually any dead weight – including gypsum wallboard (drywall). Whether a Hansen Pole Building, or not, it is just a matter of the proper loads being applied in the engineering design phase of the truss process, then (if the trusses are spaced over two feet on center) using appropriate framing between the bottom chords of the trusses to support the loads without undue deflection.

If you intend to insulate above the ceiling, make sure to ask for the trusses to be designed with a raised heel at least two inches higher than the depth of the ceiling insulation, to allow for full thickness of the insulation above the sidewalls. Normally this has little effect upon the price of the trusses, however the building must be made taller to provide the same interior clear height.

All Hansen Pole Buildings’ structural columns (supporting roof loads) are pressure preservative treated to a minimum UC-4B specification, which is the requirement per the IBC (International Building Code). Even under extreme conditions, these columns should more than adequately support your building not only for your lifespan, but also your grandchildren’s. The longevity of properly pressure preservative treated lumber has been well documented in scientific testing.

We’ve had clients use concrete permacolumns – if your concern is properly pressure preservative treated wood not being adequate for your situation, a less expensive (and easier to build) alternative would be to pour the column holes full of concrete and utilize wet set brackets.

It is possible to mix any combination of scissored and flat bottom chord trusses throughout your new post frame building to gain extra height or for aesthetic purposes.

 

 

Properly Pressure Treated Posts

Trying to Buy Properly Pressure Preservative Treated Lumber

Reader ZACH in BLACK CREEK has been challenged trying to buy properly pressure preservative treated lumber. He writes:

“Hello, I would like to get your opinion on 2×6 grade board. I read the article you wrote about lumber pressure treatment. I have been looking around for .20pcf or higher treated grade board. Called my local lumberyards but can’t get a solid answer besides it meets ground contact spec. Im about ready to give up and buy Menards since they have in stock AC2 .15pcf. I will be pouring an apron in front of building so I wanted a higher treated board. I live near Green Bay, WI but have a trucker in family. What recommendation can you give me? I attached the Menards info also.”

Mike the Pole Barn Guru 

I know Hansen Pole Buildings’ lumber wizardress Justine hears this story from unknowing and/or uneducated lumberyards all over America. At least I hope it is they do not know, rather than they do not care – which would be even worse.

Only pressure preservative treated lumber which is treated to a minimum UC-4B rating is suitable to be buried in the ground. AC2 is Micronized Copper Azole (MCA) and in order to be rated for burial in the ground, it would require a treatment level of 0.31 pcf (pounds per cubic foot) minimum. I really don’t just make this stuff up, here is the proof from the AWPA (American Wood Protection Association): https://www.awpa.com/references/homeowner.asp.

MCA treated to .15 pcf is rated only for contact with the ground, it is not designed for burial in the ground. There is a distinct possibility this product will not give you the lifespan you desire.

My recommendation – stop in at the ProDesk at your local The Home Depot® there in Green Bay (I have been to both of them – good folks at each location) and they can special order what you are looking for. Make sure to specify you want MCA to a minimum of 0.31 and get it in writing on the paperwork when you order. You will have to wait awhile to get it, so be patient.

Also – if this is to be a grade board/splash plank on a post frame building, you truly should be using at least a 2×8, as a 2×6 only gives you 7/8″ of lumber to attach the bottom of your wall steel to given the drip edge of your base trim at four inches above grade.

 

 

 

 

The Mark on Pressure Preservative Treated Lumber

Interpreting the Mark on Pressure Preservative Treated Lumber

Pressure preservative treated lumber is a mystery to most consumers, builders and even building officials. Certainly all of the above parties understand the need for pressure preservative treated lumber when it is embedded in or in contact with the ground or concrete, or in locations where there is a high probability of untreated lumber decaying.

Where the mystery comes into play is not knowing if the pressure preservative treated we are buying is actually adequate for the intended use.

Every piece of pressure preservative treated lumber is required to be either stamped or tagged with the information shown in the box above, although the format may vary slightly. Here is the secret to understanding this quality mark:

  • Is the identifying symbol, logo or name of the agency which accredits the producer – (the producer being the pressure preservative treating plant).
  • Is the applicable American Wood Protection Association (AWPA) standard and Use Category. THIS IS THE IMPORTANT ONE. For lumber to be embedded in the ground and used structurally it must be treated to a UC-4B standard. For more on this subject, what I believe may be one of my best articles ever is here: https://www.hansenpolebuildings.com/2014/05/building-code-3/.
  • The year of treatment if required by AWPA Standard/Use Category.
  • The preservation used, which may be abbreviated.
  • The preservative retention. In the “olden days”, the standard for treating was “.60” which everyone knew was CCA treated for structural in ground use. More reading on the post-CCA world here: https://www.hansenpolebuildings.com/2016/01/pressure-treatment-beyond-cca/
  • The exposure category (e.g. Above Ground, Ground Contact, etc.). This really confuses too many people as both UC-4A and UC-4B say Ground Contact.
  • The company name and location of home office; or company name and number; or company number.
  • If applicable, moisture content after treatment. This is crucial to the glue laminated column manufacturers as the glue laminating process relies upon very low moisture content lumber.
  • If applicable, length, and/or class.

Just because lumber is pressure preservative treated, does not make it all the same. Learn to watch for the level of treatment on every piece of lumber. You will be glad you did.