How to build a mezz level?

[Dunkz]

Hi guys, I'm looking for some help and advice. I'm just about ready to move into my new workshop I've spent the better part of a year building and I'd like to add in a mezz level at the top end.

I've no real knowledge about what is required strength wise. Its use would be for storage to keep the garage free from clutter and possibly a small seating area to chill out and drink beer etc.

On the image I've crudely marked the dimensions I'm working with, the plan being my right hand bay will be sectioned off as a spray booth and the left hand side a workshop. Under my artistic rendition of a staircase will likely be a toilet. Ideally I'd want to leave the front of each bay clear of any support structure so I can easily get vehicles/equipment in or out.

Can anyone advise me in how I could go about building something suitable with either wood or steel? Or maybe even block for a support column.

Any help would be much appreciated.


Sent from my SM-G930F using The Garage Journal mobile app

 

[cvairwerks]

What's the wall height? You need about 7 feet from the floor to the bottom of the mezz structure. From the picture, I suspect you could build a mezz for trolls and midgets, but everyone else would have to crawl around on it.

 

[Dunkz]

Its 3.6m to the eaves and 4.2m to the centre. I'm not concerned about head height, I'll not be using it as a dance floor. Just storage mostly.

Sent from my SM-G930F using The Garage Journal mobile app

 

[ssdave]

With the height you have to work with, I'd not put in a stair. I'd put a simple 4 column support, all the way to the ceiling. I'd put OSB on the upper part of those posts above the mezanine as shear reinforcement for the walls/columns to avoid cross braces in the area below the mezanine floor. Hang 2x12's or LVL beams between the posts, and put joists across between those using joist hangers. Plywood or OSB floor on the mezanine. I'd put a ladder to access the storage area; maybe even a captive one for more safety. With an 2.4 M clear ceiling height from the floor, .3M for the joists and floor, you'll have only .9M at the walls and 1.5M at the center, so only a stuff area for storage, not a mezanine. The stair would be a waste of space to access that. Definitely can't hang out and chill with a drink there easily! I'd consider only making the space 2 M wide, the 6M depth would be a lot of space to access without headroom to move around in it. The 9M is too wide to span with a conventional beam; you'll need to have a post at the center, or a very specifically designed beam. It might be best to make a mezzanine storage that is 2M x 4m in dimension, at the back right corner, with a single post at the corner of the 2m x 4m. Of course, if you need more storage, you can simply go wider, up to the full 9M width.

 

[Dunkz]

Thanks for the advice, I knocked up the drawings below when I first decided to build a garage over a year ago. This shows the spray booth with the trailer inside which will be fully enclosed for obvious reasons and as Ive gone on Ive decided to fully enclose the workshop too. It gets cold here in the winter so the less I have to heat the better.
The reason I'm using stairs is because I'll be putting a toilet in so very little extra space will be wasted.

Not sure how tall you guys in America grow but I'm 186cm and I dont feel that I would have any issues sitting on a chair with a max roof height of 1.5m above me. Regardless the area is mainly for storage so please dont concern yourself about available space, I'm only interested in views on construction. [emoji4]

Sent from my SM-G930F using The Garage Journal mobile app

 

[cvairwerks]

You are going to loose at least a foot in height depending on what you use for floor support and structure, and you need at least 7 feet on the main floor. That leaves you with less than 5' from the mezz floor to the roof ridge line. Might want to model that out first and see how that impacts your plans. You won't have 1.5 meters of space above you, unless you are laying on the floor....

 

[ssdave]

When I total up the heights to the 4.2M center, I don't get 1.5M above your head, I get 1.5 M from the floor.

2.4M ceiling in spray booth. .3M for the floor assembly. add 1.5M and you're at 4.2, or the center ceiling height. So, 1.5M is the Maximum floor to ceiling height, it gets less at the wall.

Unless your 4.2M total height is wrong, there's just not room for a mezanine, just a storage shelf.

A toilet under a stair can work, my point is that the stair will be essentially going to nowhere. You'll have to crawl up the last several stairs as they won't have standing height.

 

[Dunkz]

My point was that if im 1.8 tall and I sit down, im gonna total a lot less than 1.5 so height is not an issue. As ive said before, please dont concern yourselves with the height, im only interested in the construction.

Ive already had scaffold up at the height the mezz would be at and I was perfectly happy with the space. Call it a loft if you like Im really not fussed.

Sent from my SM-G930F using The Garage Journal mobile app

 

[Bob P1]

Check craigslist for a used mezzanine structure. Looks like you got a pretty clear area to fit a range of sizes. I have seen them cheap. Might be some cutting, welding involved, but that is where the FUN starts!

 

[climb.on]

Your going to need some pretty good beams to header the front and maybe the back depending on how you build the thing. If you want a clear span with no posts you could do a couple LVL's sandwiched. As one example, the LVL over my garage door has two sandwiched LVL's 1-3/4 x14" x 35' long (designed for a full clear span even though I do have 2 doors and it's carrying roof load too). If you put in posts in midspan, you could do a lot less header. You could attach an LVL to your wall posts in the back. Then 2x10 joists between the LVL's and 3/4" osb or plywood floor.

 

[climb.on]

check this thread https://www.garagejournal.com/forum/showthread.php?t=393478

 

[Dunkz]

Your going to need some pretty good beams to header the front and maybe the back depending on how you build the thing. If you want a clear span with no posts you could do a couple LVL's sandwiched. As one example, the LVL over my garage door has two sandwiched LVL's 1-3/4 x14" x 35' long (designed for a full clear span even though I do have 2 doors and it's carrying roof load too). If you put in posts in midspan, you could do a lot less header. You could attach an LVL to your wall posts in the back. Then 2x10 joists between the LVL's and 3/4" osb or plywood floor.

Hi, thanks for that. Some good info there and in the link. I guess ideally putting supports down the centre line is no issue. Keeping the spans open certainly for the right hand bay would be preferable but I could reduce it down to say a 3m opening. If I'm needing to add supports at either side along the 6m lengths it may be more awkward. Gives me something to think about anyway.

Sent from my SM-G930F using The Garage Journal mobile app

 

[bjcouche]

If you are OK with a wall down the center 6M long, then that's what I would do. Then that would split the 9M dimension into 4.9M (14.8feet). I would then use 2x12 joists spanning the 14.8 foot span. The reason for the wall is because all the floor joists will sit on the wall, and having a clear span would require a tall and expensive beam. This would be a load bearing wall, but it could certainly have a header and man door sized opening in it... If that area is going to be a paint booth then there's essentially a wall there anyhow. Actually by adding that wall, you've just made a fully enclosed paint booth with the exception of the door on the front of the booth.
Brian

 

[My Old Tools]

Here is how I did mine....

 

[Dunkz]

If you are OK with a wall down the center 6M long, then that's what I would do. Then that would split the 9M dimension into 4.9M (14.8feet). I would then use 2x12 joists spanning the 14.8 foot span. The reason for the wall is because all the floor joists will sit on the wall, and having a clear span would require a tall and expensive beam. This would be a load bearing wall, but it could certainly have a header and man door sized opening in it... If that area is going to be a paint booth then there's essentially a wall there anyhow. Actually by adding that wall, you've just made a fully enclosed paint booth with the exception of the door on the front of the booth.
Brian

They'll be a wall down the centre separating the spray booth from the workshop anyway, I guess I'll need to sit down and do the math to see what its gonna cost me between block, wood or steel but what you've said sounds about what I was thinking.
I've already spent a fortune on the garage so the cheaper I can do the mezz the better really.


---------------------

That looks really good hung from the roof although that's a lot of steel in there. Without knowing much about loading I'd take a guess at my 10 degree roof pitch not being ideal for a similar sort of setup?

 

[Vegaman_Dan]

I would be tempted to use pallet racking shelves. Get good storage below, and a solid structure for a space above. I've seen some warehouses do this for a second level in a free standing structure.

But with limited space below, that might be a limiting factor.

Do you want a recreational space up there really? How would you keep it dust free? I know the metal dust I create doing fabrication work gets everywhere. You might have to hang some plastic sheets from the ceiling to partition it off when not in use to keep the dust down.

 

[theoldwizard1]

Read these.

What you are building a mezzanine and there are many thread here on how to do it. Here are 3:

• Building a loft
  
• Mezzanine time
  
• My loft/elevated workshop garage project

Read them carefully. LISTEN to bczygan !! He was an architect/structural engineer.

 

[node105]

My workshop is 7.5x4.7m, with 3m walls and 30deg pitch roof, 75x75x3mm columns, 65x35x3mmm girts. I have 2 mezzanines ( one either end) with 125x75x4mm beams ( 2 per mezzanine) and 75x50x3mm joists at 450mm centres. All RHS, All welded.

If you want to get an idea of clearance height, do a mockup from the floor level, as the mezzanine floor height, and a length or two of timber/whatever to mimic a rafter, at the same pitch as your roof. I drew it all up and variations to try and get an idea of what would fit... but a quick and dirty mockup was really beneficial.

A 9m span - I would be thinking one centre column, or 2 equidistant columns.

 

[Homerr]

Hi Dunkz, how thick is your concrete slab? The mezzanine needs to bear on something.

Are LSL, LVL, PSL readily available in Scotland? If so, are they standard 1.75", 3.5", 5.5", 7" widths and 7.25", 9.5", 11.75", 14" depths?

If solid sawn joists, what wood species are they?

Are you envisioning more of a seating area at the middle area/highest ceiling, and heavy storage at the lower portion?

 

[Dunkz]

Thanks for all the suggestions and ideas so far guys, hopefully get time to sit down at the weekend, read through everything properly and make some notes.

Homerr: the pads under the steel are 600mm deep and 1200mm square. The floor is 150mm deep.

Should be able to get engineered lumber easily enough I'd have thought. I don't know much about it but glulam seems to be what pops up most. I'd need to look into it for sizes. I'll have a word with where I got the rest of my wood from and see what they say.

Ive got a lexus gs430 I bought for the engine with a spotless interior. I fancied turning the seats into a little chill out area at the highest point if theres space. Add a tv and beer fridge and were laughing. The rest will just be for parts and assorted rubbish that builds up over the years that I don't want cluttering up my workspace.

Sent from my SM-G930F using The Garage Journal mobile app

 

[Dunkz]

I have to Guess that you simply told the guy who built your garage, what you wanted.
Why aren't you telling him about this?

I guess you need to work on your guessing skills then. I built it myself.

https://www.garagejournal.com/forum/showthread.php?t=370358

Sent from my SM-G930F using The Garage Journal mobile app

 

[Dunkz]

Fair enough

That's a lot of build for you to be asking such basics about a mezzanine.

I just needed to know where we all stood on ability....

Building something is no issue. I have no experience on structural engineering and so I want to make sure that what ever route I go down to build it that it'll be fit fot purpose is all.

Sent from my SM-G930F using The Garage Journal mobile app

 

[Homerr]

Disclaimer: I'm calc'ing this from the US which is using our standards for loading, wood species, and performance - so check locally as ymmv. I'm using 40#/sf live load and 12#/sf dead load.

The easiest answer is to put a bearing wall down the middle to split the 9m dimension, the slab is thick enough to support this wall. Then use I-joist engineered joists, either 1) 241mm I-joists (9.5") @ 300mm (12") o.c. or, 2) 301mm I-joists (11.875") @ 400mm (16") o.c. to span the 4.5m distance to another wall build just inside your steel frame along the exterior.

Skin the top with at least 19mm (3/4") plywood, but as a storage area I'd personally go with a thicker plywood to even out loads over multiple joists better. Something like the 29mm (1.125") stuff we have here.

The joists I'm calling out here are 110 series, they could be upped to a higher spec, like 210 or 230 series, for better performance (recommended). The 9.5" 110's @ 12" o.c. fail above 56#/sf live load as a reference.

Here is a product catalog if you need to figure out conversion for local versions of these. There are standard details for construction with these here too.

https://www.weyerhaeuser.com/application/files/8215/1128/9314/TJ-4000.pdf

 

[Toomanytools?]

Disclaimer: I'm calc'ing this from the US which is using our standards for loading, wood species, and performance - so check locally as ymmv. I'm using 40#/sf live load and 12#/sf dead load.

The easiest answer is to put a bearing wall down the middle to split the 9m dimension, the slab is thick enough to support this wall. Then use I-joist engineered joists, either 1) 241mm I-joists (9.5") @ 300mm (12") o.c. or, 2) 301mm I-joists (11.875") @ 400mm (16") o.c. to span the 4.5m distance to another wall build just inside your steel frame along the exterior.

Skin the top with at least 19mm (3/4") plywood, but as a storage area I'd personally go with a thicker plywood to even out loads over multiple joists better. Something like the 29mm (1.125") stuff we have here.

The joists I'm calling out here are 110 series, they could be upped to a higher spec, like 210 or 230 series, for better performance (recommended). The 9.5" 110's @ 12" o.c. fail above 56#/sf live load as a reference.

Here is a product catalog if you need to figure out conversion for local versions of these. There are standard details for construction with these here too.

https://www.weyerhaeuser.com/application/files/8215/1128/9314/TJ-4000.pdf

This is the road I would look into, split the 9M room for the spray booth which needs a solid wall anyway. Then your looking at about 15' (4.5M) span so a 16' TJI works, the cutoffs can be used as blocking over the wall.
Going with the 110 series gives you a bit more headroom and at 12" O.C. the live load is 56lbs ( I haven't checked specs trusting Homerr on this). I don't think the 1 1/8" decking is needed it will add cost and additional weight. You just want to be sure to calculate that you have minimum or better code for live load and 56#/SF is. People tend to overload spaces like lofts with old engines, transmissions and so on.
The challenging part is getting stairs in so they don't take up lots of floor space and your headroom at the top works.