Tag Archives: skirt board

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.

 

Correct Pole Size, The Better Building Size, and Drip Edge Placement

The Pole Barn Guru assists with questions about pole size, the “right” sized building, and a picture is worth a thousand words.

DEAR POLE BARN GURU: I have a question on a pole barn.  I’m thinking of 50 by 60 and about 14ft high or so.  On the 4/4 poles, how far apart should they be.  Also on the headers, that are at the top and go all the way around, are they usually 2 by 8?  Thanks, JOE in BOWLING GREEN

DEAR JOE: Hopefully you trust me enough to believe I will steer you in a correct direction, because you are heading in a wrong one. Only one right way exists to get answers you seek, to order yourself a post frame building kit package with plans sealed by a registered design professional (RDP – engineer or architect) specifically for your building (not a generic photo copy). Done right – there will be no need to have headers all around your building, as double trusses should be placed directly to bear upon columns, insuring best possible structural connections. As to columns, they will need to be much larger than 4×4, regardless of how far apart they are spaced.

DEAR POLE BARN GURU: I am trying to design a small hard apple cider production building. It does not need to have a retail portion; that is elsewhere at our farm; just a convenient 20×30 work room that can accommodate lots of washing/spraying down of equipment, temperature control, allow vehicle entry for loading/unloading, and some viewing windows for customers to see the process. Do you have some plans/designs/kit for such a building?

Thanks and kind regards, TOM in ROSE HILL

Hansen VisionDEAR TOM: You’ll want to make certain your proposed 20′ x 30′ area will be adequate for all of your needs. You may find increasing building footprint to say 24′ x 36′ to not be significantly more expensive of an investment, whilst providing 44% more space. With every building we provide being a custom design to best fit client needs, we can certainly provide exactly what you are looking for. A Hansen Pole Buildings’ Designer will be in contact with you shortly.

 

DEAR POLE BARN GURU: 14 foot side wall panels with 2×8 skirt, what is my measurement on the skirt either from top of skirt or bottom to install my rat guard, I will have a 12 inch overhang (eaveside) using fj channel. CARL in NEWAYGOl

DEAR CARL:

 

 

 

 

Brick Ledge on a Pole Building

Brick Ledge on a Post Frame (Pole) Building

Whilst it would not be my personal preference for finish on a post frame building, there are instances when either aesthetics (trying to match other existing structures), local Planning Departments or HOAs (Home Owner Associations) mandate use of brick or stone exteriors. Whether for a wainscot or covering an entire wall (or walls) if full thickness stone or brick becomes a solution, it must be adequately structurally supported by a footing.

I truly had not given this subject much thought, until reader JASON in COLLEGE STATION wrote:

“Hello, thanks in advance for sharing some of your knowledge and experience with pole barns.

I have been looking at the construction details on your website and have a question about the bottom “skirt board”. Could this detail be designed so that the board does not show below the metal but the metal terminates on a concrete slab that extends a little? I am guessing this is how someone would do it if they needed a brick ledge. If so what is the best way to achieve this?

Thanks again for your advice.”

Jason’s question actually read like a multiple dilemma.

First, a question is hiding a building exterior pressure preservative treated skirt board (aka splash plank). Simple answer is yes, building is already designed so this can be done. Skirt board should be placed per engineer sealed building plans, showing drip edged base trim bottom four inches above grade. This allows for a nominal four inch thick (finished thickness 3-1/2”) sidewalk, driveway, landing or other concreted areas to be poured against exterior of splash plank, coming in ½ inch below bottom of drip edge. Any such pours should be along a grade sloping sufficiently away from building a minimum slope of 2%, to keep water from pooling against building.

For a nominal fee a RDP (Registered Design Professional – engineer or architect) can design an appropriate and structurally adequate support, varying in design due to individual building sites’ frost depths. Using a frost-protected shallow foundation in frost prone regions (read more here: https://www.hansenpolebuildings.com/2017/09/post-frame-frost-walls/), could possibly be part of a design solution, with some sort grade beam, whether it be poured reinforced concrete or properly pressure treated wood. Either will need to be engineered appropriately based upon material weight and strength of  soil to give continuous support.

I’d personally consider either thin brick, or a cultured stone veneer. Ultimately it will probably be least expensive design solution providing and meeting needed objectives. Framing, including columns and their embedment, will need to be engineered to support added dead loads from thin brick (depending upon pattern and thickness thin brick can weigh nearly seven pounds per square foot). Structural members need to be engineered to have limited deflection. Bookshelf girts might well be part of an engineered design solution: https://www.hansenpolebuildings.com/2011/09/commercial-girts-what-are-they/.

 

Double Skirt Boards, Siding Options, and Foundation Plans

Today’s blog discusses double skirt boards, siding options and foundation plans.

DEAR POLE BARN GURU: The pole building garage at the house I bought has two skirt boards. Can I remove the interior board to remove the dirt easier and put quikrete in its place. There is a 5” gap between the wall and the floor. The previous owner started putting quikrete in some places. Looks like the floor was put in before the building was built. KENNY in PARKERSBURG

 

 

 

DEAR KENNY: The Hansen Pole Buildings’ warehouse has the exact same situation. The interior splash plank is doing nothing for you or your building, feel free to remove it.

 

 

 

 

 

DEAR POLE BARN GURU: Can the steel exterior panels be omitted? I plan to install log siding and false log corners to match the appearance of my new log home.
Thanks BILL in WILTON

Roof Only PorchDEAR BILL: In short, yes – we can provide a building ready for you to side. What we most typically provide is 7/16” thick OSB over bookshelf girts 24 inches on center, with housewrap over the sheathing. If your false log siding can structurally provide resistance to shear, the OSB could be omitted, however this would not be my recommendation.

 

 

DEAR POLE BARN GURU: Do you include foundation plans with your kits? JOE

DEAR JOE: All Hansen Pole Buildings come with complete engineered foundation plans based upon your specific building, upon your site and reflecting the soil bearing capacity confirmed by you.

 

 

The Dual Splash Plank Dilemma

The Dual Splash Plank Dilemma

I’ve never been a fan of stacking splash planks. Even when they are center matched (think tongue and grooved) the two boards never seem to want to bend, twist, warp and/or cup the same direction leading to gaps. Gaps which lead to water getting through and spoiling an otherwise fun place to hang out doing man stuff (okay, girl stuff too) when the weather outside is frightening.

Mike the Pole Barn Guru responds:

Reader CRAIG in MONTGOMERY was less than enjoying this experience. Craig writes:

“What is the best method to waterproof the skirt boards (I have 2) so that snow melt does not leak into my building and on to the concrete slab. The lower green treat board was used as the concrete form then another was stacked on as the lowest exterior purlin. The seam is above ground and visible below the steel.”

Concrete slab in a pole barnI hate it when this happens – basically the builder used the lower splash plank (aka skirt board) to screed the concrete off from then had to add the upper one in order to have something to attach the siding to. Now you are stuck with the challenge.

I’d look upon this as a multi part solution.

First – seal the leak, a bead of good caulking (check in at the ProDesk of your local The Home Depot for recommendations) placed along the seam will be a beginning. However, this can be seen, so…..

Second – order up some Plasti-skirts (https://www.hansenpolebuildings.com/2017/08/plasti-skirt/) and cut off the inside leg so you have an “L”. Remove the lowest row of screws from the siding and dig away the soil from the base of the lower splash plank so the short leg of the Plasti-skirts can be slid under the bottom and the remaining long leg slipped behind the bottom edge of the siding. Put the screws back in place.

Third – If your building does not have continuous seamless gutters (read more here:  https://www.hansenpolebuildings.com/2012/09/rain-gutters/), invest in them. Make sure the downspouts either go into a drain which takes the runoff away from the building, or have significant extensions at the bottom.

Fourth – If you did number three, add a snow retention system to your roof to keep sliding snow from taking off those brand new gutters. Most gutter companies will not warranty their installs without them.

Fifth – Make sure the grade at the edge of your building is no higher than the bottom of the lower splash plank and slopes away from there at a minimum of a 5% slope.

Do all of these things and the concrete slab inside of your building should be a dry and happy place.

 

Purlin Questions for the Engineering Department: Building Disaster Part IV

Purlin Questions for the Engineering Department

For those readers just joining us, go back to Tuesday through Friday’s blogs to catch up to the following story…

Our client (after discussing possible corrections with one or more builders) poses this:

“I have two questions I’d like to ask of the engineering dept.

1.) Is there an acceptable way to inset the grade boards to be flush with the posts? Perhaps with hangers? If so, it would mean the wall girts would not have to be furred out.

2.) Would building frames for the end wall overhangs, and attaching them to the end trussses a viable option? Or do they feel like the end trusses would need to be lowered so the purlins can be extended?

I don’t know all of the terminology. Hopefully the above makes sense.

Thank you.”

Any proposed “solution” at this point is only a suggestion for discussion. A revised set of drawings should be produced and sealed by the engineer of record to incorporate the ultimately agreed upon repair fix.

Answers…

(1) Place a UC4B Pressure Treated 4×4 block at least 7-1/4″ long on each side of the column at the level where the 2×8 skirt board would attach. Use 3- 5″ Ledgerlocks to attach block to column. Pre-drill for them and stagger to avoid splitting. Drive 6-10d common nails through skirt board into 4×4 block. Cut ends of 4×4 block and 2×8 skirt board to be painted liberally with Copper Napthenate. Place (2) Simpson Strong-Tie LSTA12 straps across each column to tie from one skirt board to the next. Any 10d nails driven through the LSTA12 into the 2×8 PT and block would count towards the total of six.

(2) Building a “ladder” floating in space is far from an ideal solution. If they opt for this, I would want to see an LSTA24 on top of each purlin split 50/50 between blocking in the ladder and the purlin behind the truss, with 10d nails in each hole. Ladder would need to be built of 2×6 and also nailed through the 2×6 on the building side of the ladder, into the top chord of the end truss with 2-10d @ 12″ o.c.

Ultimately repairs can be simple, difficult, low cost or spendy. In the end the least expensive solution for question number one will be to furr out the girts by nailing a 2×4 flat across the columns at each wall girt. Fairly easy to accomplish and not overly expensive in time or materials.

The right way to do number two is to remove all of the purlins from the end bay, take down the end truss, cut the notches into the columns to support it (as detailed in the plans) at the correct height, and properly place the truss. This will entail the purchase of longer purlins, however it will give a much better end result.

And this my friends, is the end to my story about a building “gone wrong”.

Composite Grade Board

Typically post frame (pole) buildings have a pressure treated board at the base of all enclosed walls.

Composite GradeboardKnown also as a Bottom Girt, Grade Girt, Skirt Board or Splash Plank, it is a decay and corrosion resistant girt which is in soil contact or located near the soil surface. It remains visible from the building exterior upon building completion, and is normally two inches in nominal thickness.

A decade ago, after CCA (Chromated Copper Arsenate) pressure treating went by the wayside, many splash planks were treated with ACQ (Alkaline Copper Quaternary). When water was introduced into connections between ACQ pressure treated lumber and steel, a chemical reaction occurred, which could quickly corrode steel siding and fasteners. For the most part, ACQ treated lumber is now rarely used, having been replaced by chemicals which do not interact corrosively with steel.

In efficient post frame construction, building components are positioned and connected in such a way to form a diaphragm. The gradeboard is an integral component of a properly designed shear wall (diaphragm) assembly. Structural wall sheathing (most commonly plywood, oriented strand board or corrugated steel) is attached to the gradeboard by sheathing-to-framing connectors which are located at the bottom edge of the structural sheathing panels.

The sheathing-to-framing connectors must be adequate in size, strength and resistance to pull out to be able to transfer shear loads, which are induced into the building by wind or seismic events, from the sheathing into the gradeboard. Similarly, the gradeboard must be attached to the columns at each end sufficiently to transfer the load.

At one time I had read a posting online, which downplayed the structural significance of gradeboards. In my mind, they are a key and important structural member.

Touted as an alternative to the traditional pressure treated lumber skirt board, is the composite grade board. Manufactured in a fashion similar to composite decking, they eliminate any risk of corrosion, rotting or decay.

The composite grade board features a built-in bottom ledge, which eliminates the need for a steel bottom trim (also known as base trim or “rat guard”).

Composite grade boards expand and contract dramatically with temperature fluctuations. As such, potentially unsightly gaps must be left at each end. For a 60 degree temperature fluctuation, a 3/16” gap is required (based upon a 16’ piece).

One of the “benefits” of the composite grade board is supposed to be price. I recently did a price comparison and found 2×8 #2 and better pressure treated at 97 cents per foot, while the composite grade board from the very same retailer was $2.99 per foot (over three times the cost)!

Having used composite materials for decks and stairs, I’ve found composites to not nearly have the strength of the lumber they are replacing. Furthermore, composites seem to allow a great deal of “give” around fasteners. When loaded in a shearwall assembly, I would have great concerns about fasteners pulling through composite grade boards.

The IBC (International Building Code) gives specifics in tables for shearwall construction, none of which include an approval for use of composite materials rather than dimensional lumber framing. Alternative materials are allowed to be utilized outside of the prescriptive portions of the Code, however testing documentation to prove structural adequacy should be provided.

Me…without some actual proven test results, there is no way on earth I would structurally use, or recommend the use of, a composite grade board.