Hi All,

First time poster, so be gentle

Ive been scouring over this site and its search function, read a heap of books and visited all the websites i can find, and i still can't find any recommendations for a solid post to slab connection method.

I read with interest the issue of concrete and timber being a bad mix due to the rot that follows, and that clay/lime and timber is ok due to the wicking of moisture.

Is it as simple as cutting a notch up the base of the post and securing to the slab with an upside down T, or is a more complete steel foot used?

Any books/websites/pics you could point me to would be greatly appreciated

thanks in advance,

bumping for the new guy.

If there are perimeter walls, then place a Simpson Strong Tie Hold Down (STHD14) on the outside of each perimeter post, which will be hidden by the enclosure. CB.

what is your application?
do you need a specific calculated value for hold down?
in many cases you won't need a hold down depending on how your walls are anchored.

to keep the post off masonry use a stainless steel plate cut 1" smaller then the post, or even in some cases 1/4" ABS plastic. you are looking for something that acts as a barrier to keep things from wicking.


the image daiku points to is fine if you are out near the end of the wall. these need to go in with care as the amount of concrete above and behind can be critical.


depending on use i've used plenty of the PAHD/HPAHD hold downs. length up the post can be as critical as the detail down into the concrete depending on uplift and wind loading.

Mike:

There are so many varieties of these straps! The one that I indicated was one that an engineer once specified for me. What's the difference between the one I listed, and the one you listed? CB.

our PEng, speced a couple of simple L shaped steel pcs lag bolted to post/concrete for all four of our cruck posts. Our basement posts simply rest on concrete footings separtated by pcs of roofing shingles, just as Mike described with steel/plastic.

When we need to resist uplift and there is no wall to hide straps, we usually epoxy allthread into the slab, drill the bottom of the post, bore an access hole in the side of the post for the washer, nut, and wrench, and plug the access hole after installation. Don't forget to use a standoff like Mike mentioned. Of course, details vary and should be approved by a PE.

Clark -

There are many varieties! Seems the PE we work with usually uses one of the HPA or PA models. Not sure why - but I'll ask next time I talk to him. I think the HPA models are thicker guage than the ST models... and it looks like the design values differ depending on application.

We only use these when we are in a wind load situation and need to tie directly to the foundation (or are doing commercial work). Most residential work (with walls / shear capacity in the walls) can work by smartly tying down the walls and tying the walls to the frame.

-Mike

Daiku, i'll be sure to have a look around Adelaide for the connector you mentioned, looks like a good type of solution

BPmike, thankfully i don't need to engineer it to be held down, it was more of a "how to tackle" question than one of engineering.

the good thing about Adelaide is practically no live loading (rarely see rain or hail let alone snow!), we are only very moderately seismic here, and no heavy winds to worry about, but i'll have the connection to slab over-engineered anyway for peace of mind.

thanks again all hope to pick your brains again soon!

Timberlinx

I've used these a few times now, I like them alot, they will level your post bottoms....