Boatjob1

I am considering putting a freestanding 24 by 16open (top covered)boat storagebehind my office for a boat. What is the best way (without cutting the pad) to mount a 10'vertical treated 4 by 4 to the concrete (also is it required that it have a spacer or can it be direct to the pad). I know Lowes sells 12+ inch supports for this with one 5/8" concrete lag and about 18 holes to secure to the 4 by 4, never used one of these plus they are $15 to $17 each.

Also on a 24' span (length), should I put 3 post (8 foot spread with cross ties, twoend postand one center) or put 4 post (every 6 feet). I actually check with you guys on the PFF before I even Google it now, because you have ALWAYS come up with great suggestions. This is not a demand project, just looking at possible options.

Thanxxxxxxxxxxxxx. Tom

Buzzbait

Dude, do it right for a couple extra bucks/hours. Cut the slab, set your posts in a good foundation, and pour back around your posts. With the spans and length of posts you are talking, this weekends winds would blow it over. Maybe not but you get the idea.

Sweet 16 by the way.

fred

One lag into the concrete does not sound like enough to me. If you get the ones that have about four bolts (properly drilled and grouted/epoxied) they will be as strong as most jobs you would do concreting the post into the base unless you excavate under and put a bulb of concrete on the post.

The length of span ismostly dependent on the size of the beams from column to column and the load of the roof, but the bigger consideration is the posts.Six (or even 8)ten foot 4x4s would be awfully spindly in the winds you can get down there. I'd go with something more like 6 ea, 6x6s and you would probably still want somewooden fishplatesat the top for stiffness at the joints. Or you could go with 4x4s and add some X-braces.

Another consideration is whether or not you want the roof line to be nice and straight or if you will tolerate some sag.

This thing sounds like a pretty good airfoil to me so I'd bolt it down well.

Here's a link to Southern Pine span tables.

http://www.southernpine.com/spantables.shtml

The spans are for joists, but you can treat your outside beam (girder) like a heavily loaded joist and get an idea for sizing

Xanadu

If you're putting any kind of real roof on it, you need 6x6s and to cut the slab, bury the posts 4' in the ground with a 12" hole filled with concrete. You need 3 per side and a permit.

The Raven

Honestly, if I were in your shoes I woudn't do a surface mount on a concrete slab when you have that much exposure to the elements. I know you don't want to cut your slab, but that is the "best" solution for what you're describing.

WereI doing this project I'd cut a 16" square out of the sheet and go about 36<U>" minimum</U> into the ground with the upright, fill around it with concrete right up to level with the top of theslab again. By the way, I agree with Fred's recommendation of bigger lumber, buried deeper.

When you anchor those posts into the slab you risk your entire structureif you have a single point of failure. Put a high wind load on that roof and one of thoe anchor nuts strips out and the whole structure will turn into a missle. I know it sounds unlikely, but it's really not. In a hurricane the wind loads on those corner posts will be significant.

Boatjob1

I knew I came to the right place with this question. THANXXXXXXXXXXXXXX, your input answered a lot of questions for me. I was actualy able to score (3) 23 1/2' by 6' commercial aluminum frame awnings, and was thinking with some modification what a great boat storage top they would make. Thanks again for the info. Tom

ironman

If you decide to cut your slab, DO NOT cut a square hole. Get a core drill and drill a round hole or chip thru with a chipping gun in a round pattern.Your slab will crack in the corners of a square cut hole.

CATCH-ALL

Where's Joe/ 1Bandit when you need him? He's a builder. He could answer your concerns with several solutions.

Catch

Xanadu

You probably can. Post a picture of them including the attachment point to the ground. Sounds like you're just going to need to pour yourself some footers with threaded rods to attach to your frames.

Pinksnappertrapper

Sounds to me like you should get a pole barn kit. Boardfeet on the forum sells them for a decent price. He owns Pensacola Salvage Yard #8 in Milton. He just posted a price for another forum member the other day.