Under Construction, need some advice!

[Shadrack]

Been registered here for a while, but just now posting. Great site with lots of good info! Actually, browsing this site has given me a lot of ideas to use in my new garage/apartment.

I'm building a 50x20 (inside demension) garage with a split level living area. Total downstairs (including the bathroom) will be about 1,100sq ft and the upstairs will be right at 750sq ft.
13' ceiling height on one half, and 7'8" on the second half.
12/12 Sissor Trusses on one half, and 12/12 Livable Attic Trusses on the other.
Garage door will be a 16x10.

Started this project at the first of November and it's been slow going due to the weather. I'm open up for suggestions on ideas of different things so if you see something that could be improved post up!
I'm planning on it flooding sometime down the road (next to a creek obviously), hence why I used block on the lower 3 ft of the garage, and, using 10' studs gives me the height I need for my 2-post lift.

The old garage and out-building will be gone that you see in the pictures this summer, as well as all the trees once this new garage gets complete. I'll then start a foundation of my house overtop the existing pad of the old 22x36' garage once I get my garage paid off. Nothing real fancy, but it's all I'll ever need.Trusses will hopefully be up this week, and I'll post pictures as progress allows.

Now, on to the pictures and the problem......

Okay, the problem is this.......

How to span this 20' (21' plywood to plywood) with NO SUPPORTS underneath? I was settled on the idea up until now to go with 16" floor trusses. However, those are going to run me $1,500 and I'm pretty sure those are overkill. However, it's better to be safe than sorry and with me being an engineer that's how I think.

However, after searching this site, I found span charts and I'm now leaning towards 2x12x22's (cutting to fit) to span the distance on 16" centers. According to the charts (if i'm reading them correctly) I can span a 19'11" span with a 60psf live load + 20 psf dead load. Would this be strong enough to support, say, a pool table with several friends? I'm not a structural engineer so I don't really want to dig into my books to figure all that out to be honest, lol.

The way I plan to attach the 2x12's is to sandwhich a 2x6 against the wall joist and set the 2x12 on top of it, then under the 2x12 (going horizontal on the wall) installing a 2x4 as a cleat. This would effectivelly make my free-standing span 19'9" which falls within the safe limits of the load chart. Would this be strong enough or, is my thinking all backwards? lol

Any help is appreciated, this is my first time designing and building anything.

 

[kbkna]

I spanned 20' in my house using 2x12 yellow pine but I doubled up each and went 12" OC. Overkill yes but I have no flex or squeeking floors.

 

[ddawg16]

16" OC will have bounce...I would go 12" OC and make sure you use 1" T&G plywood....plenty of nails....that should reduce the bounce

 

[Falcon67]

And glue/screw in the subfloor. 3/4 ply with construction glue and deck screws makes a hell of a solid floor.

 

[5lima30]

Have you thought about using LVL beams? It is hard to find straight 2x12's when you get over 20' and LVL's are very straight IMHO. Pricewise depending on your location they maybe an affordable option. I personally like them because it is easier to run electric and plumbing. YMMV.

 

[Shadrack]

What are LVL beams? Never heard of them I don't believe, just floor trusses and 2-by's around these parts! LoL

Are there a manufacture of these beams close to Eastern KY?


The reason for wanting to with 2x12's is because it will gain me almost 6" of upstairs wall height, which REALLY helps when it comes to usuable floor space using a 12/12 pitch sissor truss (8/12 on the inside). A lot of the trusses/beams/I-joists are 18+" deep. With a 2x12 my upstairs wall height would be right at 4'3" or something like that.

I wonder if I could double up (one on each side of the wall joist) every other one for added strength, and doubed up underneath where the pool table will set. Hmm....

 

[Holedgr]

I would recommend floor trusses as opposed to 2x12's or TJI's. Google 'em any you'll see why. Not too much off doubled 2x12's cost..



-T

 

[blkhonda1991]

if you use 2x12's id go with 12" oc for a stiffer floor especially if you are using this as a gathering space for your buddies...the way you plan to attach your 2x12s to the wall concerns me though not having it sit on a wall but rather a cleat. you mention you are using attic trusses...are you sure those are what you have because if that is the case they have the floor joist built in and should be designed to take a certain amount of loading depending on their design.

 

[snorky18]

I don't want to drag this too far off topic, but how do you get 1100SF downstairs from a 20x50?? 20*50=1000SF

 

[Shadrack]

The attic trusses on half of the garage has 2x8's on the bottom chord.


I'm not using only a cleat to set joists on. They will be setting on top of a 5' 2x6 that is setting on top of the block that will be nailed to the 2x6 wall stud. Essentially it will be sitting on a post, and the cleat is there just as a little bit of added support.

I've called around, and I've found 12" deep floor trusses for $55 each. They can hold 55psf on a 19.5" OC load (what the guy told me on the phone). Would this be enough to support 3/4" flooring, pool table, and say 15 buddies on a superbowl night? LoL

 

[Shadrack]

I don't want to drag this too far off topic, but how do you get 1100SF downstairs from a 20x50?? 20*50=1000SF

I have another door next to the hillside (notice gap in studs) that will lead to an attached room measuring slightly larger than 8'x12' as a bathroom and a location for my air compressor. That will be poured AFTER the main garage is complete.

 

[snorky18]

I have another door next to the hillside (notice gap in studs) that will lead to an attached room measuring slightly larger than 8'x12' as a bathroom and a location for my air compressor. That will be poured AFTER the main garage is complete.

Oh good, a simple explanation. Now back to your regularly scheduled programming

As far as your floor loading, do you have a building inspector you have to satisfy, or are you out in the sticks where you make the call?

Interesting description here on floor loading:
http://www.trimjoist.com/loads.html

and here on spans:
http://www.trimjoist.com/spans.html

 

[Shadrack]

Out in the sticks!

I've found a local place and decided on 12" deep floor trusses. Will be here tomorrow!

 

[blkhonda1991]

Out in the sticks!

I've found a local place and decided on 12" deep floor trusses. Will be here tomorrow!

dont forget your fastening detail needs to be revised now that you are going with a floor truss instead of dimensional lumber...the flange at the bottom is wider than a 2x and you wont be able to nail it into the stud from the side

 

[larry_g]

As my daddy used to say " Ready, Fire, Aim " I hope all this works out for you. Its still not to late to draw up what you have, what you propose, and run it past an engineer to double check what your doing. It would really ruin your day to have a party with you 15 friends suddenly move to the first floor or all the balls on the table keep congreating on one rail of the pool table.

lg
no neat sig line

 

[garage_man]

Use the floor trusses, i highly recommend it, it will be flatter, less deflection, much better insulation value, easier to run ductwork or anything else you need to do.

it will save you money in the long run!

 

[Shadrack]

I talked with the truss company engineer pretty in-depth and he told me that what I am using it for a 12" truss will be perfectly fine, even with a pool table. It conforms to residential loading and can hold a 55psf live load (10psf dead load top and 5psd dead load bottom) at a 19.5" center spacing. I'm putting mine on 16" centers and will be using 3/4" T&G plywood so I shouldn't have any problems.
The trusses measure 20' 10" and will be setting on two 2x4's nailed together and nailed to the 2x6 wall studs, making the trusses basically setting on a 4x4 post.

Hard to describe, but I'll post pics.

 

[6768rogues]

The spacing center to center should be 19.2 inches, not 19.5. You will have 4 equal bays in 96 inches. If that follows the truss designer's specs, I would use it. You will get a stiffer floor with closer spacing, but also use more trusses. Typical residential live load is 40 psf for the first floor and 30 psf for the second floor, considering in the design a 1/360 deflection at full load.

 

[Shadrack]

While I had him on the phone I asked him about how I wanted to have them spaced and attached. He said the recommended spacing is for insulation purposes mostly and would have no problem with 16" spacing.
He also said at full load, deflection will be somewhere around 1/2"

With making a "post" to set these on I'm going to have to come up with a little different way to run wiring I believe. Hmmm.......

Next thing go figure out is how to transition from the floor up to the attic trusses. I'm thinking I'm going to have to space the last sissor truss and first attic trussat 24" center to allow enough room for stepping up/down into each room. It's about a 5'-6' distance. Once the floor trusses and attic trusses are installed I can tell more about it I believe. What I have pictured in my mind will work...... I think, lol.

 

[Shadrack]

That's an 8' step ladder upstairs, and a 12' step ladder leaning against the floor trusses. I didn't think it would be this big. Looked much smaller on my AutoCAD drawing. LoL!

 

[NUTTSGT]

Looking good, it'll be sad when the river rises.

 

[Shadrack]

Ahh, it's just a little creek. Since the 50's the highest it has ever been in that little small garage pictured was 12" deep. That was in 1977 I believe. I'm actually planning on it flooding sometime down the road. It can get 32" deep inside the garage and shouldn't really hurt anything major. Would probably have to take a garden hose and few wheel barrows full of mud out of it. LoL!
It's not the ideal location, I'll give it that, but the land was free and when you live in the mountains of East KY you build on any flat piece of land you can find no matter what! haha

 

[Kevin54]

Ahh, it's just a little creek. Since the 50's the highest it has ever been in that little small garage pictured was 12" deep. That was in 1977 I believe. I'm actually planning on it flooding sometime down the road. It can get 32" deep inside the garage and shouldn't really hurt anything major. Would probably have to take a garden hose and few wheel barrows full of mud out of it. LoL!
It's not the ideal location, I'll give it that, but the land was free and when you live in the mountains of East KY you build on any flat piece of land you can find no matter what! haha

I'd build any benches or storage in a fashion that they were not on the floor. For that matter, I think id build up an area in the back that I could get the toolboxes up on and out of the way just in case of a flood. If you know that it floods and the deepest so far has been 12", you should have designed it in a way that it was a little more than that above ground level and had a large concrete ramp to drive up into it. Fires one thing when it comes to insurance, but if uyou don't have flood insurance and you live beside a creek....well you'll be up that creek without a paddle.
On the other hand, the garage is looking good and looking forward to the next installment of build pics

 

[Cobra5150]

Ahh, it's just a little creek. Since the 50's the highest it has ever been in that little small garage pictured was 12" deep. That was in 1977 I believe. I'm actually planning on it flooding sometime down the road. It can get 32" deep inside the garage and shouldn't really hurt anything major. Would probably have to take a garden hose and few wheel barrows full of mud out of it. LoL!
It's not the ideal location, I'll give it that, but the land was free and when you live in the mountains of East KY you build on any flat piece of land you can find no matter what! haha

Check out the flood in Welch WV, I think it was 2001. What's upstream from you? Any coal mining in the area? I had a video of a stream about that size that had never flooded. At one point you can see a couple of the neighbors houses go by.

 

[Shadrack]

Surface mining is all around me. I'm a mining engineer, and I'm not real worried about that compared to the volume a 100 year storm can drop. I don’t care where you are at, when you get 3+” of rain in an hour, it WILL flood. As long as they designed all their structures correctly flooding shouldn’t be much of an issue caused “by mining”. So far, their structures have proven well designed because they completed mining almost 10 years ago. Actually, since the late 70's the interval and severity of flooding has decreased tremendously due to the fact of proper surface mining methods came back and took out all the "pre-law" disturbances and installed properly designed hollow fills and sediment structures. Contrary to popular belief, it can be proven in SedCAD (soil modeling program) that surface mining can and will reduce flooding potential, but that’s beside the point.
What happened, and why it flooded last time (20+ years ago) was that a log came down and wedged itself between a bottleneck that was downstream about 300' and it backed everything up. This area was pointed out to the state/county and FINALLY two years ago they came down and widened the creek and installed gabion baskets to remove this area completely. Since then, the creek hasn’t come close to leaving its banks (before hand, it averaged about 2-3 times a year).
As a matter of fact, the houses that are immediately across the creek (where my family lives) are only setting up about 1.5-2’ higher than this concrete is. Those coal camp houses were built in the 1930’s.
Flooding is something I’m planning on it doing sometime down the road. I can sweep and clean out the floor that isn’t a problem. ALL my expensive air tools, wrench sets, etc will be hung and organized on the wall via peg-board (keeping them out of the bottom shelves of the tool boxes) and all my socket sets will be on the top shelves of my tool boxes which will put them above waist high, and the two cars that I’ll be storing in there will be up on jack stands about 2 feet high. If water gets waist high (or above the block) in this garage, I have A LOT more serious problems to worry about than this garage trust me, lol. During a 100 year storm (6.50” of rain in a 24hr period), or if the upstream small lake dam (city water intake) bursts the water level will be at the guardrail in the upper road, or WELL up into the 2nd floor. Like I said, I’d have a lot more to worry about then, lol. There is approximately 4-5 miles up stream before you get to the headwaters. The stream is normally flowing (summer months) only about halfway across the creek bed. Right now it is at an elevated level due to all the snow melt we have been having.

I also forgot to mention even though it's hard to tell, but the height of the pad of the new garage is about 6" higher than the pad of the old garage. I wanted to build it up about 2 feet, but where was no way I could build it up that high without any fill material and it would take thousands of dollars worth of gravel to fill it in that high. I would have loved to have it build up about 2 feet, but that's something I couldn't really do much about at the time. We took a bobcat and dug the footer, filled up the low spots (almost a foot in spots), then poured 6" of concrete above that. Annnnnnyways, it will flood eventually I know and understand that, but until then I’m going to enjoy my new garage hopefully for 50+ years water free!

Dang…. Sorry for writing a book, lol.

 

[mobetta]

Looks good, I like the design.

I am interested to see how you transition to the RIA truss's.




way back in 07 the area in SE MN that i grew up in got up to 15.1" of rain in 24 hours, smashing the state record of 10.8".
huge devastation.- tiny streams swallowed valleys, roads wiped out. hopefully you never see that.

 

[Shadrack]

Exactly, if we got that kind of rain, our entire city (small town really) would be washed entirely off the map! Everything is built down into the narrow valleys because the mountains are just too steep for the majority.

I've got it drawn up and I think what I have planned will work alright I believe. At least, I'm hoping so! I'll post pics of the progress when it comes to that point for sure!

 

[NUTTSGT]

To be properly prepared you could buy a few hundred of these.


http://www.uscav.com/Productinfo.aspx?productid=17824&TabID=1&CatID=1436

 

[Shadrack]

Nah, I figured a 2x12 with rubber gaskets would do the trick!

 

[Shadrack]

Cleaned up a bit and starting hanging my electrical boxes. I've got 12 total downstairs. Spaced about 10' apart. I think I'm going to add a few more. The electrical boxes are 48" off the floor, so a 42" work bench will work perfect on the left hand side under the lower ceiling area. Hope to have it fully under roof by the end of the week.

 

[mobetta]

more outlets. now is the time, it is very cheeep to do. i have no less than 35 duplex outlets in my 26x26. 5 dbl gang boxes on each wall(no more than 5' apart), then some more here n there, plus the ceiling and lofts.

post some details of the roof framing transition when you get there.

 

[FJ 432]

I remember being at that point in my project and how excited I was so you're probably jumping out of your skin right now. Nice build and yes add more outlets.

 

[Shadrack]

I'm thinking I'm going to space them 5' apart to get more boxes on the first floor.

Yeah, I think I've got the transition figured out, at least in AutoCAD anyways, haha. Looks like to make it work perfect I'm going to have to cut, rebrace and slightly modify the last sissor truss to give just a bit more clearance for the stairs. I put one more sissor truss than I did attic truss to give a 16" overhang from the end of the last floor joist. But the transition will not start until the OSB board and metal roof is installed to help support/tie it in before I go to cutting. Should work out pretty good I'm hoping.

 

[kbs2244]

Sounds like you have it figured out.

 

[mobetta]

Updates??

 

[Shadrack]

Ooooops, forgot about this thread, haha......

Haven't taken any pictures for about 2-3 weeks but here are the latest pictures I have.

Since this pictures, roof is complete, wiring is done, lights are done (for now), stairs are not 100% finished though. I still have some work to do to get it tied in perfectly, but it will at least give you all an idea.

 

[blkhonda1991]

couple questions, did you fasten the joists someway from the outside like you would if you had a rim joist? how did you support the joists you cut short?

 

[Shadrack]

Set a post on the cap board on the block and nailed them to the 2x6 stud, then set the floor truss right on top of those and nailed them down into the top of the post and toenailed them into the 2x6 studs. Once the avantech flooring went down, it's ROCK solid.

 

[mobetta]

looking good- thats a bigass door....

 

[Shadrack]

My buddy's call it a moving wall, lol.

Updated pictures....