Serious weight bearing build

[Jaws]

I'm in the process of planning a 160" long by 100" wide fish room on the back of my wrap-a-around deck on the second floor of my house. The deck is completely open below so adding support will not be an issue. After the room is built I plan on doing an in-wall tank off my dining room. My main concern right now is weight bearing since this is going to my dream setup which means display tank, sump, frag tank, refugium, quarantine, the whole nine yards. The deck is currently lag bolted every 16" into the house wall that the display tank will sit flush against. The joists run perpendicular to the tank and wall and are every 16" as well. The back of the deck is supported by 6X6 posts off each corner but don't have any underground footings so I am fully aware I will have to add multiple support posts and beams in various places below the fish room to support the weight.

The display tank will be just under 400G: 84L X 36W X 30H. On the back corner of the fish room will be a 3 foot high wrap-a-around bench. The part of the bench bordering the back wall will have a 100G refugium as well as 2 55G mixing drums below the bench sitting on the deck floor. The part of the bench bordering the wall on the right side of the fish room will have another 100G frag tank on top. Below the bench on this wall will be a 120G sump sitting on the deck floor.

I do realize that this is a little crazy but I think any of us that are in this hobby are a little crazy so really I'm just following suit I've owned this house for four years already and don't plan on leaving anytime soon. I got engaged a few months ago and we're planning our wedding ceremony on our property so this is a little bit of an engagement present for us both too since she also loves the hobby

I'd love to speak to someone with any kind of engineering background that could lend some kind of assistance with the build. I can call you anytime that's convenient for you or email works well too. Any suggestions would be greatly appreciated. Thank you.

[04V10]

Hey Jaws,

Looks like you have quite the setup planned. There are a few things that we need to know first to help out where you can properly support this project. However, I am telling you now that you are probably going to lose your bottom patio doing it.

What type of earth do you have under your concrete slab? Is there much clay, approximate level of the water table where you are at? What type of wind loading are you going to be seeing on the walls of this project. What speed?

First you have to look at the stringers that you currently have in place. They are in no means a way to anchor something that big, and to ensure that you don't put excessive loading on your exterior wall of your house, you are going to want to put post supports at the wall of your house. One at each corner and at least one in the middle at the wall of your house. Considering the weight of the contents you're going to put on the deck, you will probably want to put pilings in. Another thing to look at is the sloor supports.. Might want to get engineered trusses in. The third is another post in the middle at the exterior of the concrete slab.

This may be overkill, but where I live the ground is extremely soft...lol

[sphelps]

Extra support is obviously needed but any posts will have to be placed on piles, just placing them on the slab is probably a bad idea. The posts already in place should be on top of large piles, the same should be done for any additions.

I have no idea if it will work or not but an idea worth considering is talking to a larger hut tub company and request a quote for installing a hot tub in the proposed position of the tank. Many hot tubs are as much as 500 gallons so weight would be similar and seeing how this is probably an application most companies have dealt with before they may have some ideas on what is needed. The key is to pretend you want a hot tub there

[Jaws]

That's a good idea about the hot tub. lol

The ground is mainly dirt, gravel, and rock with very little, if any, clay. I've been told by neighbourhood residents that we're all gravel and rock out there and that's why it's so hard to get gardens to grow without replacing the soil every year. I'm not too sure about water table level or wind loading. Any idea how I would find that out??

My initial planning was to add two 6X6 posts parallel to the outside posts but at the back of the patio area. Basically to the left of the entrance door downstairs and at the far right, just right of that window. Plus I'd add two more 6X6 posts directly under the tank. A 6X6 beam will sit above the posts as well. I would cut a 12X12 square out of the concrete slab for each post, dig down maybe a foot and pour a concrete footing with a bolt to attach the posts to. I have to be mindful of the perimeter drain in front of that window though too.

The front and open part of the patio is another concern right now. I do have a tenant and I would like them to have a small area to stand outside without getting wet. They don't need to be able to entertain down there but the more open the better. I also want to make sure I can get a wheel barrow or a lawn mower through the garage door on the right easily enough so I'm open to ideas on how to support this section. I already planned on adding another 6X6 post on the left and the right of the deck running parallel with the front posts and a 6X6 beam above them but I don't think that will be enough support in the center to accommodate the 210G of water above it. Correct me if I'm wrong though.

For the wall with the sump against it I have some 2X8's that I'm going to beef up the floor joists to make an 8X8 beam that will also rest on and run perpendicular to the support beams that are running parallel with the house being held up by the support posts.

[lastlight]

800+ gallons total volume on the deck! I'm not qualified to give any advice to anyone besides your tenant: close the door to your suite GENTLY.

The amount of work in new posts, footings and joists to make this safe is going to be immense. Please consult an actual engineer and not just the hot tub folks! I will def be following along this is certainly different!

[Reef Puffer]

when we built a house for a customer a couple years back they wanted a large hot tub on their deck (like a 12 man i think it was). when it was all said and done (after the engineer finally signed off) the deck was built with 1 3/4"x 16" LVL beams every 12". it looked like HUGE overkill to me but im not an engineer either. the deck was about 14' by 18' and stood about 10' off the ground. i cant remember exactly what was done for footings under the deck but im sure it was just as extreme. good luck with the build!!

[lastlight]

I was thinking LVLs too but again I'm no engineer... tho i *am* an engineer dropout if that makes any difference?

Also...

[sphelps]

Originally Posted by lastlight

...Please consult an actual engineer and not just the hot tub folks! ...

I'm an actual engineer, first person I would call are the hut tub guys

[lastlight]

Originally Posted by sphelps

I'm an actual engineer, first person I would call are the hut tub guys

I never made it to third year so maybe I missed all the practical stuff

[StirCrazy]

Jason, you need to get a building permit to do this, and the city of victoria will be able tto help you with the requirments. Ie. how many piles and ect.

you could do it with out one, but..... if you have one niebour who calls you have to tear it down.. if you go to sell the house you have to disclose you built it with out a permit, or if they find out they can sue, ect... since you are putting a big tank in there your going to want insurance coverage, no permit no coverage.....

I did a simular adition (not for a fish tank) but to close in a deck on a friends home with him. Because it is attached to the house and will be closed in all the regulations change from the min code from a deck to the house ones.

we had to sister bigger joists to each one under the deck, we had to cut the concreat under the deck and dig out for footings (which had to be inspected before we could pour the new cement. and so on and so on.

my recomendation to you would be to go to the city and inquire what would be required to turn a 2nd story deck into house living space. do a basic drawing of it or take the pictures you posted here and a sketch of the size and information like what the joists are size wise and how long, how far apart and what kind of exhisting supports you now have. you don't need to tell them it is for a big fish tank, just add more footings and beef up the floor suports later.

we did all ours with a home owners permit, but we had a footing inspection, and a structure/electrical inspection. I found they were most concerned with the way we were going to tie into the house, the support and the electrical. the inspector asked us how we were going to insulate and saw everything sitting around so he decided he didn't need to come back and see that and the Vapor barrier ect befor we drywalled when he was at the electrical inspection. I assume you going to have plumbing so theres another permit and thoughts.

I have books here with lumber types and what weight you can handle with size and span, so if you PM me some numbers I can let you know minimum amount of suports and size of the new joists and beams you'll need

Steve