Acceptable shims for post to pier connections
I’m in the concept phase of trying to come up with a design for a new 3 season porch to replace my existing open porch. One of the challenges I have is that I only have 17″ of clearance between the ground and the exterior door to work with.
I’m still wrestling with using joists over beam versus inline beam. My current preference is joists over beam. Something like 2×6 joists over 2 2×10 beam or 2×8 joists over 2 2×8 beam. Still playing around with the layout/numbers.
My plan is to use the Simpson post connector and rest the beam in each one. I will have to be precise in getting the piers to be exactly level but I suspect that there will be some minor differences that I will need to shim out.
What are acceptable shims to use and where can I get them? My thought was that I would embed the j-bolt in the concrete and then shim the post base to get to the right height. I understand Simpson has those adjustable post-base that seems to rest on a single bolt but they don’t look that sturdy to me. I would rather shim the standoff so I think I need to get metal of different thickness.
What are your thoughts? Thanks!
Replies
Inside I would use steel plate but you probably need aluminum or stainless outside.It will be bleeding rust after some years. That is one reason why I am not a fan of the galvanized Simpson products outside. They make them in $$ stainless too.
If you go to a scrap yard they may have some aluminum plate scrap. That is usually where I look first because it is only a bit above the scrap price. You might even stumble into some stainless. I usually grab a bunch when I find it.
Otherwise try a fabricator.
Shims
I have an assortment of plastic shims I got from steel workers. From very thin up to 1/2".
That's what I'd use.
Remember, choose beam and joist size for the span and load, not to make up 17 inches.
Thanks for the advice so far. Yes, I'm aware of the various tables for joists/beam span. I was discussing this with my local building department and he stressed the need to make sure that the beam is resting in all of the post brackets without any gaps. It's possible that I really don't need shims as long the brackets are all within 1/8" because wood will naturally deflect slightly so they will touch without gaps.
So it sounds like I need to fabricate my own shims from metal or plastic. I was hoping that you could easily buy them somewhere in various thicknesses such as 1/16", 1/8", and 1/4". I'll ask my building dept for some advice on shims.
Whichever shims I use will have to be stainless or plastic since they'll be exposed to the weather.
I'd be inclined to use the commonly available plastic shims. The main problem with them is that they tend to be a bit on the thick side.
What is the compressive strength of that plastic?
Better than wood.
Wood is pretty soft too across the grain. The post puts the load in line with the grain. I guess I have just never seen a wood shim used in this application.
On the other hand I don't see a lot of wood used in structures down here anyway. Too many things eat it.
I meant that the compressive strength of the plastic would be better than the end grain of the wood, which is to say it's all that one needs.
Would these plastic shims be a common item stock at a lumberyard? I can't recall ever seeing them at my local yard. I'll ask about them the next time I'm there.
gtm
The shims I think dan is talking about are maybe 6-8 inches long, thick at one end, not as thin on the other as a cedar shim.
There's also plumbing shims (toilets) that notch together to hold them in place.
What I was talking about was a flat certain thickness plastic shim. Used in steel setting-ask an ironworker if you can. Otherwise, I'd just start google searching using the previous keywords-that google thing is pretty intuitive.
They come REAL thin up to 1/2-3/4" that I know of. Easy to use and will last most anything nature can throw at it.
Best of luck.
Wood?
Your posts are wood, your beams are wood, and your joists are wood, perhaps your shims could be wood, unless you need your shims to outlast your construction.
Oh, I forget, "what do your drawings say" and "have you had this engineered"? LOL
do right.
you forgot another axiom
You cannot shim a beam with wood shims. (whether or not it's a wood beam, a paralam, a microlam, steel............
Ask your local jurisdiction.
You can shim a door or a plate at the stud or joists or alot of things with wood.
But something that carries a combined concentrated load will crush wood over time. Since these concentrated loads are often sitting on masonry, they can also become saturated or go through that wet/dry cycle that plain ass 'd rots 'em.