Tag Archives: hairpin rebar

How to Prevent Existing 6×6 Columns From Future Settling and Rotting

How to Prevent Existing 6×6 to Prevent Future Settling and Rotting


“I recently acquired some property with an existing pole barn “house” on it. It is an unfinished 20’x30′ room with corrugated steel siding, a trussed, steel covered roof and several doors and windows. It was built with a raised floor attached to the 6×6 treated beams set deep into the rocky soil. Before I make any improvements to the inside of the structure to make it livable I am wondering if there is any process I can do now to set the existing 14 6×6 supports on concrete piers or a footing to prevent future settling and rotting. I cannot see any existing concrete surrounding or supporting the vertical 6×6’s. I would hate to invest anything on the inside of a structure that was not set on a good foundation.”

Mike the Pole Barn Guru writes:
If your existing columns are showing no decay signs then they are probably adequately pressure preservative treated. You could excavate around each column, to below frost line. Hole diameter (to provide sufficient bearing surface) should be determined by an engineer, however for sturdy soils and small spans, usually 24 inch diameters will be sufficient.

Drill each column, in both directions using a 5/8” bit, six to 12 inches above column base. Insert a #4 re-bar dowel (#4 is 1/2″ diameter) through each hole.

Galvanized re-bar is recommended. Otherwise, coat rebar penetrating column with an asphalt emulsion, or similar, to isolate re-bar from pressure treated wood.

Seal rebar, into bored holes, at each column edge with silicone caulking.

Before backfilling holes with premix concrete, make sure floor is level. If not, slowly jack floor up to be level with highest point and temporarily brace.

A recent study has shown concrete in contact with pressure preservative treated pine may encourage premature decay by brown-rot fungi. As such, we strongly recommend isolating such columns from concrete starting at splash plank top (roughly 7-1/4″ above grade), to 14 to 18 inches below grade by use of a moisture impervious barrier. Then backfill holes with pre-mix.

If premature post decay is apparent, here are some other options: https://permacolumn.com/pdfs/perma-column-rotted-posts-repair-guide.pdf

When Pole Barns do not Have Footings

Reader KEN in FORT COLLINS writes:


We just bought an acreage with an existing 36 x 48 post frame farm storage building. In talking to the prior owner, we have learned that the builder did not use cookies, footing pads or a cement bottom collar. So nothing to prevent settling (He did nail uplift cleats on each column. ) We are concerned about the building settling. The building is two years old and is straight and level now.

Question: Our question is if we pour a five inch thick concrete floor and install hairpin rebars in each column will this provide significant protection against settling? If not what remedy would you suggest? Your sage advice would be appreciated!”


I say this because Larimer County requires building permits on all post frame buildings and they are good about doing inspections. How this one escaped their watchful eye is beyond me – and sad, because now you (new to you building owner who cares) are stuck trying to solve a challenge which never should have existed.

Which leads me to – you might want to contact the county to confirm a Building Permit was issued for your post frame building and it was signed off on by the field inspectors. If it wasn’t and your building fails a smart insurance company will get out of paying a claim to replace it. You may also have some recourse against the prior owner for not disclosing the building did not have a permit.

Back to the problem at hand.

Builders like this give our industry a bad name and me headaches.

Tying the columns into a concrete slab on grade with rebar hairpins might prevent both settling and uplift forces. It might also just crack your concrete.

The best solution, in my humble opinion, is not the easiest one, which would be to excavate each column individually to eight inches below the column while supporting the building nearby. Slide an 18 inch or taller piece of sonotube up from the bottom of the column (unless you have some overly heavy roof load, loft or bonus room in the trusses 24 inch diameter should work on sidewalls, 18 on ends), place it on undisturbed soil, with the column in the center and pour the tube full of premix concrete. The soil should then be compacted around the tube and the upper portion of the excavation.

Mike the Pole Barn Guru