This week the Pole Barn Guru answers reader questions about the use of steel posts for a lean-to, converting an existing pole barn with an open wall into a one-bedroom tiny home, and columns for a post frame remodel and addition.
DEAR POLE BARN GURU: I’m building a lean to up against my 40′ high cube container using 11′ galvanized steel posts that are 2 3/8″ diameter at 13ga. Poles are set in concrete at 3′ and plan to set 7 poles every 6′ on center for a total span of 36′ from center of each end post. Will be using 2×10 treated wood for rafters and 2×4 treated wood for purlins.
My question is are 7 poles every 6′ center overkill or can I get away with 5 poles. Roof will be 26ga. Galvalume.
Thanks,
DAVID
DEAR DAVID: I personally would not attempt to build any structure based upon steel posts. You really should invest in services of a Registered Professional Engineer, who could give you answers you can hang your hat on. Much better than waking up one morning and finding your lean to either flat on ground, or blown away into your neighbor’s yard.
DEAR POLE BARN GURU: We have a 22′ by 32′ pole barn with 3 metal sides, front open no flooring. We would like to turn into a 1 bedroom tiny home for our daughter. Can it be done without breaking the bank? STEVE in EFGEFIELD
DEAR STEVE: Before you get too deeply into this, you really should engage a Registered Professional Engineer to visit your building to determine if it is structurally capable of being converted for residential use. Most pole barns are not designed to residential standards, so your engineer can advise as to what repairs/upgrades will need to be made.
Typically fully engineered post frame, modest tastes, totally DIY, move in ready, budget roughly $70-80 per square foot of floor space for living areas. Does not include bringing in utilities or any permits.
DEAR POLE BARN GURU: We have a future project coming up and the customer wants us to take half a existing building and take it from a 9′ side wall to a 16′ sidewall. My question would be should we use the existing laminated column and just off set the joints or remove the posts and start fresh for that half? CHANCE in CASPER
DEAR CHANCE: You will want to place a new set of columns for this taller eave portion, both from a practicality standpoint, as well as liability. Any time you structurally tie into an existing building, you now become liable for any failures associated with it, whether you actually has anything to do with it or not.
Also – maybe consider rotating roofline of taller portion by 90 degrees to keep weather (e.g. snow) from dumping off in front of new overhead door.
DEAR KAITLIN: Most pole barns are built either without being engineered or to Risk Category I. For residential purposes, it would need to meet more stringent structural requirements of Risk Category II. You will probably have to add some perimeter slab insulation in order to meet Energy Code requirements. My best recommendation is to engage a Utah Registered Professional Engineer to do a physical evaluation of your existing building and to design needed structural upgrades.
DEAR WESLEY: I have seen many far less well thought out wall systems without exterior sheathing not experience issues with condensation. As far as air sealing, you could get a blower door test done to find out exactly what your situation is. For extended reading, please see 
DEAR TRIPPE: We always suspend our columns eight (8) inches above bottom of holes and mono-pour footing and concrete encasement in a single pour (saves on paying for short haul charges). While concrete typically reaches 75% of compressive strength in seven days, when I was building we would pour one day and start building next day. For slabs on grade, it is recommended to not walk on them for 24-48 hours after a pour. Keep in mind, concrete compressive strength is in psi (pounds per square inch) and soil bearing capacity under footing is in psf (pounds per square foot). Most soil will support a maximum of 2000 psf or 13.88 psi, so your concrete (at 2500-3000 psi) is going to be much stronger, even after a very short time span, than soils beneath. You can increase concrete strength by ordering a higher cement mix and speed curing time by use of hot water (avoid use of chemical additives to speed curing).
