Stand Construction - Post Spacing Question

[Anonymous]

See the pictures below of the posts for the stand I am building for my 300G.

I am going to have a 150G sump underneath the tank that measures 24X48X31. I used a dummy board the size of the sump (24X48) to make sure it would fit in the stand before I screwed the verticle posts in place. The posts on the front can be equally spaced. The posts in the rear cannot.

Does anyone foresee this as a problem?

The spacing shown above would allow for the placement of the sump after the stand is complete. I could add another support after the sump is installed but would rather not. The span in the rear between the two center posts is 44".

Louey

 

[Anonymous]

4' is a bit much, depending on what your top beam will be. If you're thinking about using 2x4 or 4x4, 44 is too much. But if you do some research on structural beams, you should find an answer that you can live with.

But if you're skinning the back (where the big gap is) with 3/4" ply, you should be okay. (but why not put in a brace then!)

B

 

[Anonymous]

I am planning on using 2X4 cross braces. I figure a horizontal brace at the top, center, and bottom across the front and sides. I'll probably skip the center brace in the back for accessibility reasons.

Of course there will be a sheet of 3/4" marine grade plywood across the top. I would screw that down a million times across all of the posts and upper verticle framing members (not shown at this time).

Louey

 

[Anonymous]

I would think if you used 2x6s across the 44 inch gap much like a header over a door/window you would be more then fine.

 

[Anonymous]

JDM wrote:

I would think if you used 2x6s across the 44 inch gap much like a header over a door/window you would be more then fine.

That would add two more inches to the height of the stand, which is already going to be 42" tall. I'd rather not do that. I would take 2" off the 4X4's, but that would be a PITA and another trip to HD. (My radial arm saw won't do 4X4's). BTW, my car can make the trip to HD without any assistance from me at this point. :lol:

I am thinking if I take my horizontal bracing between each 4X4 then also tie the end posts to the wall on each side, there shouldn't be any way for them to move.

Louey

 

[Anonymous]

Could you add an addition 2x4, cut 2 inches shorter, next to each 4x4. You can use that as the brace for the 2x6? The main theing you need to worry about is having the top sag over that 44inch gap.

 

[Anonymous]

Could you add an addition 2x4, cut 2 inches shorter, next to each 4x4. You can use that as the brace for the 2x6? The main theing you need to worry about is having the top sag over that 44inch gap.

I could probably do that. I may have to move the 4X4 a little further away from each other, to facilitate the sump, but that may be worth it to get the 2X6 in place.

Louey

 

[Anonymous]

I have a couple of stands that I built with 4 ft span, but I used steel tubing for the supports that won't sag like wood. Wood will sag no matter what, you just need to make sure it won't sag significantly that detriment the strenght of the stand.

If you want to use the 2X6 without changing the dimension of your stand, you can use a 2X4 across the posts like you planned, then glue&screw a 2X6 right next to the 2X4. The thicker stud is for making sure the gap won't sag, not to support the weight (the 2X4's job).

There are tons of possibility.

 

[Anonymous]

do you have a circ saw? You could rabit out the posts and put the 2x6 in the posts. then cap with a 2x4

 

[Anonymous]

Can a circular saw cut 6 inch down the post like that? I will use a regular hand saw.

 

[Anonymous]

How's this look?

Remember, the whole thing will get horizontal bracing out the wazzoo.

I may insert a verticle member in the center of the span once the sump is set. I'd rather not, but I will if the concensus says that it may prevent a disaster. The 2X6's are 57" long FYI.

Building this stand is a PITA. Tile floors and unlevel floor are the devil. The frigging devil I tell you.

Louey

 

[Anonymous]

your 2x4's are much stronger the other way. (up and down rather than lying down)

And since you're adding them in, I'd definately go with 2x6 Glue them together and screw them from both sides.

Someone here or even at RC put up a mechanical engineering deflection drawing for someone. You might want to find the post and send a PM. Or maybe see if there's a free calculator on the net somewhere.

B

 

[Anonymous]

your 2x4's are much stronger the other way. (up and down rather than lying down)

Those are 2X6's. They are glued and screwed on both sides. I can't face them the other way because they would block my access to the sump. The sump is 31" tall. I built the stand to have 6" clear above the sump. These 2X6's are already infringing upon that clear space. I'll just have to deal with that. I don't want the stand any taller.

I'll add another verticle post (a 4X4) after the sump is in place. That should take care of it, no?

Louey

 

[Anonymous]

yeah. then your span is only 20" or so. which should be fine. But make sure it goes clear to the floor. Use a couple of angle brackets to put it in place. If you ever have to get the sump out, you can pull the brace for a bit and then put it back in without taking the whole tank apart.

Make sure your cross braces go up and down.

Is the tank going to have bottom trim, or is the glass going to be on the plywood (with foam of course)

B

 

[Anonymous]

I was just looking at the home depot website. You might look into a post jack.

JS-36 Super S Series adjustable jack post. Adjusts from 3 ft.1 in. to 1 ft. 7 in. and is tested to 16,000 lb. at maximum extension and 18,000 lb. at minimum extension. Corrects sagging floors, supports basement beams. Support for room additions and remodeling projects. Takes weight of large furniture or appliances. Support for porches and decks. Levels and supports RVs or manufactured homes.

I looks like you might be able to put it in place, the if needed lower it and remove it. It was around $20.

 

[Anonymous]

That adjustable jack looks like it might work out nice to support the center span.

Today I did and major change to my stand. The unlevel floor and tiles was giving me fits. Trying to put bracing underneath the subfloor to carry the weight of the posts was maddening. Once I started shimming one side to level the subfloor, I was sure that my bracing was no longer sitting on the floor. So I chopped up the subfloor so that new post could be put it so that there is no doubt that they were on the floor.

I also started some horizontal bracing on one side. I tied the side post to the wall using tapcons. Those two end post are solid as a rock.

Time for a beer now. I am starting to hurry my work, and that's when I know it's quitting time.

Louey

 

[Anonymous]

PS - thank god for sawzalls. :lol:

 

[Anonymous]

Posts are utilized in framing where you need an open span. On top of the posts you set a beam to carry the planned weight over the span of the posts. The most important part of the design is the top beam. You don't even really have one and then you turn it on its side.
You should have just built a 2X4 wall around the area you are enclosing. Sheathed in 3/4" playwood, it would carry anything you put on it. With double plates on both top and bottom it would spread the weight over your floor and supply ridgid support for your top plywood. The only place you would need a beam would be over you doors. By the way, this whole thing could be built in 4-6 hours. Why do you think post and beam framing isn't used on your home?

 

[Anonymous]

Hey, I'm not a carpenter.

So you really think I should put some beams across the whole thing on the top, then put the plywood on top of the beams?

I thought the posts were carrying the weight and that the plywood would spread the load. As long as the post are adequately braced, they can't move from side to side, and therefore the stand would be rigidly built, no?

louey

 

[Anonymous]

If you look at how commerical stands are built, you will notice that cwa46 is correct. However, this does not mean that we can't built something that is strong enough for a tank... military tank, that is.