24x32 in Southern Illinois - New member.

[Don_P]

The lateral loads, usually the wind pushing on the building, on a typical foundation are carried from the house down to the ground through and around the perimeter foundation walls. Pier, girder, joist and post above would be the typical way of supporting the internal posts in platform frame construction. However that system also requires a perimeter foundation to take the racking loads down through a wall to the ground. What you are proposing and what I've drawn is quite doable but well outside of the cookbook tables and methods in the codebook. When that sketch is close enough to doodle dimensions on it's time to go talk to an engineer to work out the particulars.

[interex]

So, this is my progress so far...  tomorrow all the beams and end braces will be done, then time for the joists.

May not be a preferred method, the way I bolted everything like this... but it seems to be much stronger and has so far been less expensive doing it this way.

The braces are all bolted on both sides of the posts/beams.  The beam was very sturdy and appeared to be very strong and with having 40 posts for a 24x32... I don't see myself having much of an issue with doing it on these huge piers.

[Don_P]

This is well connected but is unbraced. Welding the flat plate into T or L sections or attaching Y braces is what provides lateral rack bracing. Steel and fasteners in contact with treated should be galvanized or at least very well primed, the copper in the treated wood in contact with mild steel is a low voltage battery arcing into the steel whenever moisture is present.

[interex]

Do you mean Y bracing under the beam on the sides of the post?  If so, I've not got that far yet.

As for the metal, it will all be coated with what is similar to that used on bed liners/undercoating, to prevent rusting, so that should cover the current/voltage concerns.

[MountainDon]

Coating on the face that is in contact with the PT wood is the important face.

[John Raabe]

I would suggest getting a load trace as has been mentioned earlier.

Doing solid blocking at every post, and tying beams and posts together with heavy bolted plates as you are doing is a good start. Stick framing the walls and floors and then sheathing everything with well nailed structural sheathing will also add a lot to the rigidity. Still, you don't want to get up to the loft floor and realize there is a new load coming down you hadn't anticipated.

Some questions pop up with the work so far:
• Is there enough room under the girders to get around the crawlspace and work on plumbing and wiring? Minimum is often 16" under joists and 12" under beams/girders - and more is better - especially for guys of any girth.
• Is there a moisture stop between the posts and the concrete pier?
• Do you have to consider insects such as termites?

[interex]

Coating will be on both sides of all metal, even the angles on the strike anchors at the piers.

As for is there enough room?  Yea, at the north end we're at 16" high on the posts, at the south end we're at 8-9"... and probably enough to do what needs to be done.

As for a moisture stop, I have black plastic that I probably should put down... completely overlooked that part.

We haven't ever had an infestation where I live, not to say it can't happen... but any preventative measures to ensure there isn't a future problem are useful.

[John Raabe]

A piece of asphalt shingle makes a good moisture stop under a post. There are metal termite shields that force the critters into some discouraging acrobatics to get to the eatable wood but that's probably not needed by the sound of things.

[Squirl]

If they are a little larger they also double as good rodent shields. Rodents love elevated floors over posts.  The wider the better.  




I'm not sure how effective they would be at 8".

[interex]

Okay...

All beams and posts came down, all metal was treated with an undercoating/bedliner type spray which was recommended to protect the metal from the elements, as well as to the PT Wood itself.

Everything turned out rather well, and is all assembled.  Once all the bolts were back in place, I coated everything on the outside a second time to fill in any gaps, etc...  And just so it is out there, each post is plated on both sides with 1/8" steel, using 3/8 (2") screw/lag bolts.  We used 10 plates and 60 bolts per beam/row.

So far my cost on the metal/coating and bolts is easily under $150.

Tomorrow, depending on the rain, I should have the beams ends cut evenly and the ties installed.

It's really strange, but using my 5' level/ruler everything is perfectly level from end to end on all beams... but using my 2' level/ruler, a lot of it is off level here and there on each beam.

[Don_P]

The longer the level the more accurate... if the level is accurate to begin with. Turn them around and double check when in doubt. A short level is finicky. Our mason brought out his machinists level to show this past week. It's good to 5 ten thousandths per foot and cautions about walking near or even breathing on it... too much accuracy for my work! A transit, water level or laser would be best for your girders if you can get hold of one. Do brace the piers both within the row and 90 degrees to that, from row to floor before getting much weight on them.

[interex]

Do brace the piers both within the row and 90 degrees to that, from row to floor before getting much weight on them.

You lost me here... can you explain a little more?

[Don_P]

The posts can be pushed over either front to back or side to side so they need to be braced within the row and between rows, make sense?

[John Raabe]

You want to triangulate the posts with 45º braces to the beams. This adds rigidity to the floor and foundation framing. Installing braces the other way - from the posts into the floor joists - helps brace the other direction.

[interex]

Right, I just haven't got that far, for the 45 degree braces under the beams.

Today was a good day, we got a lot of things done, and hopefully tomorrow I will be able to get all the bracing done.

[interex]

Curious, can SYP (non-PT) be used for the joists instead of PT ?

I'm putting black plastic down over the beams before I put the joists down, and will be putting insulation between the joists.

Just making sure I don't over do it, nor under do it, ya know?

[Don_P]

Treated is required if the bottom of the joist is closer than 18" to the ground. You don't want plastic on the bottom, cold, side of the floor assembly, it'll condense.

[interex]

Measuring today, it appears that the top of each beam is 18" or above in every location except one, where it is almost 17 1/4 inch.  I'm probably going to just dig that mound of dirt out and make it the same.

Therefor, untreated SYP should be okay.   

Another concern... if I put the joists up today and it rains before I can get the insulation down and covered, will the joists be okay, being untreated?

Lastly, if putting insulation down between the joists, how do I hold it up if I can't use plastic?

[dug]

Another concern... if I put the joists up today and it rains before I can get the insulation down and covered, will the joists be okay, being untreated?

Once it is up and nailed in place standard lumber can take quite a beating from the elements and still be fine, I lost count of how many times my framing got soaked. A bigger concern would be keeping the insulation dry, which is not as easy as it may seem. Tarping will work O.K. until you start getting the walls up, but then becomes difficult to impossible. I think it's worth considering waiting until the roof is up before insulating the floor, even though it may be harder then.

Lastly, if putting insulation down between the joists, how do I hold it up if I can't use plastic?

There is a thread that covers that pretty well here-

http://countryplans.com/smf/index.php?topic=11124.0

[interex]

Thanks for the reply Dug.

Looks like I'm off to buy my floor joist lumber today since it's the last day of a really good sale, I'll be saving about $130 compared to off-sale price.

Would it be safe to put down something like 1/4" mesh on top of the beams, before the joists are installed, to cover the entire span of the foundation?

[John Raabe]

Would it be safe to put down something like 1/4" mesh on top of the beams, before the joists are installed, to cover the entire span of the foundation?

Not sure what this is asking. Is the mesh wire? Are you trying to keep the foundation dry?.. protect the beams?

[interex]

All I'm trying to do is keep the floor warm in the winter time.

I'm asking what measures I should take in order to do that.

[MountainDon]

Right, I just haven't got that far, for the 45 degree braces under the beams.

One thing to remember is that any bracing or connection is usually only as strong as the fasteners.

A few posts back in the thread it was mentioned that the steel plates were fastened to the beam and poier material using 3/8" diameter lag screws that were 2 inches long. The engineering advice I have seen on lag screw diameter and length to develop maximum strength calls for the Length of the threads engaged in the main member to be at minimum 8X the diameter of the lag. That would be three inches of thread should be engaged in the main member for a 3/8" diameter.  

The main member here would be the beam or the post and the steel plate is what is known as the side member, or member to be secured to the main. The main member is the larger member, the side member is the piece that the lad passes completely through.

The maximum strength being talked about is the shear strength of the connection. Withdrawal strength is much less than shear, as a rule; especially so if the thread depth in the main member is less than ideal. Maximum strengths are developed with proper sized pilot holes in the main member; 9/32 in softwoods for 3/8 lag.

http://countryplans.com/smf/index.php?topic=6925.0

Just threw all that in for future readers/viewers.



Half inch is the minimum recommended diameter in code, if I recall correctly.

[interex]

I used 1/8" steel with 2" lag bolts, so that means I have 1 and 7/8" bolt into my post and beam, is that not acceptable?

Also, while 1/2" diameter might be recommended, will not 3/8" diameter be acceptable?

I have a total of 12  3/8" diameter (2" long) per post... 3 on front, 3 on back per post,  and 3 on front and 3 on back per beam...on the plating. 

[John Raabe]

To answer the earlier question about insulating the floor. Go ahead and install the joists and subfloor and then all framing and all up to the roof. Once fully died in and your joist cavities have all the plumbing and wiring installed then do the insulation and fill to (at least) the bottom of the floor joists. Then put a product that is an air barrier but not a vapor barrier, such as Tyvek on the bottom followed by the mesh you suggest which will be the critter barrier. If you are doing a critter proof skirting you can eliminate this last step. This assembly will keep air from carrying away heat from the floor insulation yet allow the flooring to continue to dry out.

RE the bracing bolts. What is acceptable is a question for your inspector or perhaps an engineer who knows all the specifications of your specific soil, lumber and local wind and earthquake zone. The information Don is sharing are guidelines for getting the the most bracing support out of the bolts and hardware you might consider using. Certainly using shorter bolts is better than no bolts or using just nails.