Trimming Posts, A Taller Building, and Post Treatment:
DEAR POLE BARN GURU: Trimming posts or adding Shims? My pole barn kit uses steel trusses that sit on top of the posts and bolt to their sides. If I set two or three posts lower than the rest, can I just add a shim the top (using PT plywood or similar) to match the heights of the other posts, rather than cutting the tops of the other seven or eight posts?
How much mismatch is acceptable? Would a 1/4″ difference in the tops of the posts be acceptable or noticeable? MIKE in ORLANDO
DEAR MIKE: I will give you my answers however prior to implementation of anything I advise, you need to be contacting the RDP (Registered Design Professional – architect or engineer) who designed your building and sealed the plans to get his or her approval.
In my humble opinion, using a non-compressible shim in order to make up the difference should be a non-issue.
As to the acceptable mismatch, structurally the ¼” difference will not make a difference, however there is a good chance it will be noticeable to the naked eye, especially along either the eave girt or fascia board. The closer you can get to perfect, the better the result will be and the happier you will be with it.
DEAR POLE BARN GURU: Hello guru! We have a project on the way, and were thinking that our building the way it is engineered is going to be too short for our needs. What kind of risks, be it enforcement or safety would we run into if we increased the building height 2′? BRAD
DEAR BRAD: From a practicality standpoint all of your columns will be two feet too short, as will the wall steel. From an engineering standpoint going two feet taller changes the required sizes (dimensions not just lengths) of some of the columns. If you want taller overhead doors, then you have yet another issue.
The risks – safety – you would now be putting up an un-engineered building, which would be under designed for the loads being imposed on it and could collapse, causing injury or even death. Enforcement – if they catch you, you would have to do field modifications to bring the building up to Code.
If you are serious about making it taller, we can work with you to come up with the least expensive fixes and material swaps. The sooner you decide, chances are the less expensive it is going to be, however there would be a non-refundable deposit involved as we are going to put in some serious hours on this whether you decide to go forward or not.
DEAR POLE BARN GURU: If PCP is not good for health and longevity on a pole house replacement pole. 2 each at 30’….what treatment do you recommend on a DF pole? JOE in KAILUA
DEAR JOE: If you are using Douglas Fir, then the pressure preservative of choice is ACZA. You could also use ACQ, however it is very corrosive to steel fasteners, so you would want to have products with a very high level of zinc in the galvanization process, or use stainless steel parts.