Post Footing and Site Leveling
Reader KEVIN in PAOLA writes:
“I’ve been working with Cory on my building design and had a question regarding leveling my site and setting my posts. The plan is a 40′ x 60′ building with a 17′ eave height. On the south side, there will be a 12′ attached shed that is open. Based on the elevations I’ve shot, I’ll have to add approximately 4′ of fill on the east end of the building and it gradually tapers all the way to the west end. Now, rock on the property is rather shallow. I dug a test hole on the east end which will require the most fill and the rock is about 2′ below native ground level. I’ve encountered solid limestone that is approximately 2′ thick when digging corner posts and I’ve found locations where the rock is fractured and can be dug out with an excavator. The county requires poles be installed at a minimum depth of 4′, but will allow 30″-40″ if due to rock and if the holes are backfilled with concrete.
· How would you design the foundation for the poles?
· Does the 4′ of backfill count when measuring post embedment?
· Would you set the posts first and then add the fill?
· Do you change post foundation design as you move from the deeper fill for elevation on the east end to fill on the west end that is replacing the top soil?
· Does the post foundation design change for the open shed on the south side?
I’m attaching the design doc from the county. Foundation information is listed on pages 8 and 9.
I hope all of this makes sense and thank you for the help.”
Thank you for reaching out to me. With your permission, I would like to treat your building as if it was my own (in other words, What Would the Pole Barn Guru Do?).
Starting with your door end (which I will assume is uphill), I would add enough fill so this end could have holes dug to 40″, filling balance of site accordingly. All fill should be compacted in no less than six-inch lifts to a minimum of 90% of Modified Proctor Density (you may need to invest in a Geotechnical Engineer to verify compaction).
Foundation would be embedded columns to 40″ depth and would be same for all areas (our engineers will seal holes at 40″ depth) Properly compacted fill can be relied upon to be equal to undisturbed soil Fill first – it is so much easier than trying to work around columns.
On door end, you will want to grade away from doors, so water coming down hill does not end up running into your building.
o model Building Codes – IRC (International Residential Code) for one and two family dwellings and their accessory structures, and IBC (International Building Code) for all other buildings. Neither code has a requirement for full foundation to support pole (post frame) buildings. I would encourage you to reach out to your local Building Official to ask for further information – it is possible your village or township may have enacted a specific ordinance, to this case, if so – request a written copy of the approved document and please forward it to me for review. In most instances, no such ordinance exists and, if so, this ‘requirement’ cannot be legally enforced.
DEAR POLE BARN GURU: Are they hurricane proof? LINDAONGLEY in DAVENPORT 
DEAR POLE BARN GURU: I have a new monoslab with 20″ footer all around. Slab is also reinforced with 1/2″ rebar. I want to build a 40’x46′ pole barn. Walls are 14′, roof trusses are 5/12 pitch. Can I use Simpson brackets and place 6″x6″ posts on top of the concrete every 8′ with 2″x6″ girts? Or should I have builder put posts in the ground around the slab? Thanks-ERIC in REXFORD 
DEAR LUCAS: Fully engineered post frame buildings adapt themselves very handily to being erected over a full, partial or walkout basement. We can engineer to have wet set brackets placed in concrete, concrete block or ICF foundation walls, or can provide post framed Permanent Wood Foundation walls. We encourage our clients with basements to utilize clearspan wood floor trusses, to create wide open spaces in basement levels, as well as to allow for utilities to be run through floor trusses, resulting in flat finished ceilings.
You should replace all nails with screws of a larger diameter than nails and 1/2″ greater in length. Look for screws with EPDM washers (not neoprene rubber). If you find a location where water leaks have caused wood deterioration and screws are not “biting” place a wood ‘filler’ in hole – we’ve heard of people using wooden match sticks for this purpose, however would recommend ripping some small squares (roughly 1/8″ square) out of Douglas Fir using a Table Saw.
DEAR CRAIG: While it might be possible to raise a portion of the roof, it should only be done with involvement of a Registered Professional Engineer who can make a determination of adequacy of what you have, and what would need to be done to insure structural adequacy. Chances are good columns in area to be taller will need to be larger in dimension to properly withstand wind loads.
DEAR POLE BARN GURU: 
DEAR TONY: 
DEAR LLOYD: There is no structural reason to pour a “rat wall” between columns (
