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-   -   Need advice from a structural engineer: makeshift garage (http://www.hotrodders.com/forum/need-advice-structural-engineer-makeshift-garage-79569.html)

Zimmo 01-22-2006 11:01 PM

Need advice from a structural engineer: makeshift garage
 
Hello,

Im planning on putting a car in a shed to work on. Its a small light-duty wood 15x15 shed that was not designed to support a car, and its on a hill. It is supported by earth at the door area, and 4x 4 posts on the perimeter. There is no center support; just 2 by 4s running across. The grade drops 6 from the front to rear.

What would be the best way to reinforce this structure to support 3600 lbs? Im thinking about using 4 by 4s below the shed, running horizontally directly below where the tire load would be. I would put another 4 x 4 on the ground (Should I used pressure treated for this?). Then I would box it in with 4 x 4s running up & down. Basically building 2 ladders lying on their side below the shed on the centerline of the tires

Will this be strong enough? Will the strength be compromised due to the angle of the 4 x 4 that follows the grade of the ground?

Thx.

oldred 01-23-2006 07:55 AM

First off I would strongly recommend finding another place to work but if you do this then probably you should dig into the ground at least 6"-8" and pour some concrete(the redi-mix bag type at the building supply will work fine)and use blocks on that to support the bracing you must add to the floor. Basically you should envision a ramp suitable to support the car built under the floor with the floor not being part of the structure but resting FIRMLY on the ramp. The thickness and size of the concrete pads should be determined by the firmness of the ground but about 20"x20"x3"-4" should be ok if the ground is reasonably firm. Again I would STRONGLY recommend finding another place to work!

Zimmo 01-24-2006 12:22 AM

Thanks for the info. The crankshaft in my wife's car is broken. I wish I had a garage or other garage options, but due to the cost of a replacement engine it's not possible right now (My custom garage is in next years budget :D ). I was going to attempt it outside in the backyard, but the only level place is the floor of the shed (unless the front yard counts LOL)...and it's a little cold here too.
I'll do the ready mix thing you suggest. How long does it take to set up in below freezing temps? Also, should I put the studs in first before running the horizional beam?

I figure if I run enough 4 by 4 studs planted in concrete along with 4 by 4 beams (or bigger) it should be stong enough.

OneMoreTime 01-24-2006 01:17 AM

Garage tent
 
Actually before I did all that I think I would get one of the portable garage tents and set it up in the driveway..probably cheaper..and safer..With a bullet heater those are not all that bad to work in..

OMT

Kevin45 01-24-2006 03:02 AM

If the shed is basically sound you could cut the floor out and use pavers on the bottom set in a gravel base. or use 4 x 4's set about every two foot apart and use treated 2 x 6's on top of those for the floor. Do not use any standard lumber on the ground or it will be a termite smorgasboard in a matter of weeks. If your present 2 x 4 floor struxture is in contact with the ground you may possibly get by with using 2 x 10' or 2 x 12's underneath the tires to distribute the load rate. Get two of these to drive and park on. You would be surprised as to what it will hold. As a matter of fact I would probably go that route before attempting to pour a floor.

Kevin

oldred 01-24-2006 05:56 AM

I was not suggesting pouring a floor just some pads for the supports to rest on. It is very hard to get a level, firm support on just the ground and if the blocks/4x4s move or sink even a tiny amount it could result in disaster. Whatever you decide to use I think you should use the pads for firm footing since that small amount of concrete would cost very little and would not be at all hard to do. If you use the 4x4s (6x6s would be better) then you could just dig holes about 8"-12" deep and anchor them in the ground. Remember you have to be concerned with more than just the downward force of the weight and if you use long wooden posts for support it is extremely important to get them straight and/or brace them from the side(X brace maybe) since if they start to lean even slightly the lean could quickly "snowball" and collapse.

If it is below freezing then you can get an additive to put in the concrete to help it set. Think this through thoroughly and try to picture what could go wrong BEFORE it does and this should work.

Onemoretime has what I think would be an excellent alternative with the portable garage(Harbor Freight has them on sale right now) which would in all probability be cheaper and a heck of a lot easier.

Be careful and good luck :)

1939P7 01-24-2006 06:33 AM

The centers of the 2x4"s or what ever is supporting the floor and
the sheathing/flooring material would be the most important structural issue . Since your saying 15'x15' I would think the existing floor is dependent of further support from the ground or what ever is down the center of the floor. 2x4's or 4x4's at a 15 foot span at 16" or 2' centers
are not safe for your needs 2x6's on 12" centers would be.
Sheathing of at least 5/8"on 12"centers would work but the issue of supporting the car(jacking and jack stands) could be a safety issue.

I agree with "OneMoreTime"The portable tent as mentioned is most likely your best route, tax free, less work than you would encounter in (rebuilding) a safe structural floor.
"you may possibly get by with using 2 x 10' or 2 x 12's underneath" that idea would work also, you can overlay them on the existing if it is solid and sound .

Last but not least, you can jack up the existing structure and pour a 4" reinforced floor and set anchor bolts in the pour for the plate and then lower it and then you have a good work area.
http://i41.photobucket.com/albums/e290/1939p7/HFH1.jpg
Getting this section of this house in the air compared to what little work you would encounter for the structure you have wouldn't be all that hard.
http://i41.photobucket.com/albums/e290/1939p7/HFH2.jpg
I'm not by any means a structural engineer, but I have done some off the wall jobs for a friend of mine that worked .
http://i41.photobucket.com/albums/e290/1939p7/HFH3.jpg
I would check your township building codes before you do anything, unless you out of site
and don't think you would run in to a problem as I did when we had the barn moved with out a permit for any of it, at first. Weigh the work+ the cost+time and labor and the tent might be your best al arounf bet.

Zimmo 01-24-2006 06:59 AM

Pics
 
4 Attachment(s)
This is it (& the wifes car) see attachments.

I've thought about the tent idea, but when I load up the cherry picker with weight I doubt I could move it in the snow. I'd really like to make the shed reinforcement idea work.. ;)

BTW - the posts on the sides are 6x6's.

1939P7 01-24-2006 07:56 AM

Now I can see what you have, the pic's explain a lot.
You have 2x6's across the width "free span" and only the
corners of the building are supported . (?) Are the 6x6 post
in concrete ? or just in the dirt?

The reason I ask is it would be easer(the way I look at it)
to pour a floor in front of the structure and move the building on it.
Other wise you have a whole lot of work to make that safe to pull a
car in to work "safely". Then the ramp is another issue. if you have to pull
the engine I would do that outside with a few sheets of 3/4" plywood,
get the engine in the building and do what's got to be done .

I would be on pin's and needles trying to work on a car in that building
where it is situated. There appears to be many variables as to it's location,
structure and support/s etc .

If you had a slab poured about 1 " minus the outside dimensions of the building ( this is to allow overhang of the siding material so water doesn't get under the plate, again it's a lot of work ) , you could then separate the walls from the floor and roll it over on pipe with 4x6"s running towards the slab after reinforcing the walls . Bottom line, it could be done but the weather is a major factor . The tent looks better with every post. :mwink:

Zimmo 01-24-2006 08:40 AM

The posts are just in dirt. I don't want to get too crazy with this thing - like pouring any foundation, but if it's gonna cost me the same in lumber & Ready-Mix as a tent garage...maybe I should reconsider.

Shelter-King

Beenaway2long 01-24-2006 08:59 AM

Zimmo-
That would take you well over 40 hours to reinforce, at a cost around $1,000+. Then it would only be a marginal death trap.

At a BARE minimum, you'd need to remove the existing floor, and replace with 2x12's at 12" on center. Then , for flooring, you would need 2x6 laying flat, with something like 3/4 plywood over it. The wheels would still dig in to the plywood. You would also need more post supports to support the weight. And they would need to b X'd. And at 15' deep, you would need the door open to work in there. Remember, the cherry picker would need to have enough room to be pulled out to drop the motor on the ground.

And I didn't even address the fact that the shed posts MAY be rotted. They WILL need to be set on a solid foundation. Concrete SHOULD not be poured below freezing. Will not set. Just freezes. No strength. There are additiives, but not good for novices. Things like Antihydro will burn your hands if not propery equipped.

At WORST, get yourself a tarp, some rope, and a salamander heater. Roll the cherry picker on a few sheets of plywood on the ground.





Disclaimer: I am no engineer. No "internet engineer" should be trusted either, without providing a certified soil sample, moisture/rot sample of existing structure, etc.

woodmanscott@hotmail 01-27-2006 08:51 AM

shed for a car
 
[QUOTE=Zimmo]This is it (& the wifes car) see attachments.

I've thought about the tent idea, but when I load up the cherry picker with weight I doubt I could move it in the snow. I'd really like to make the shed reinforcement idea work.. ;)

BTW - the posts on the sides are 6x6's.[/QUOte my grand mother lived next to a man in ga that had a wooden floor in his garage fir atleast 30 years and it is still holding..he had 2x12's on 12" centers then he took 2x6's and used them for flooring he used to layersone layer turned 90 degrees to the joist and the second layer 90degrees to the first and it has held up my truck and it weighs in around 10,000 lbs but mind you that the joist dont sit in hangers they rest on a 4x6 supportted by 6x6 post on 4 centers around the perimiter and in the center of the flloor he added later 4 2x12 with 3/4 ply wood glued and screwd together and it is sitting on 6x6 as well ... but you dont have to go all that far if you dont plan on making it so that you can pull big trucks in there .. i would put 2x12 under the tires atleast 3 on each side and then cover the floor with 2x6 pressure treated (cause there mainly pine that they treat ) to spread outthe load on the floor..but dont forget about when you load up the cherry picker with the engine that part of the floor needs some help let me know how it goes

Zimmo 01-27-2006 09:07 AM

Thanks for the advice guys ;)
I'm just going to put together a quick 2 x 4 frame arount the car where it sits now & throw a tarp over it - instead of reinforcing the shed idea. I don't want to get to crazy on redoing the shed structure...I'll put down a couple sheets of plywood & get a torpedo heater...

Regarding the heater, should I get L.P. or kerosene fuel?

Thanks again :thumbup:

woodmanscott@hotmail 01-27-2006 09:12 AM

heater?
 
Quote:

Originally Posted by Zimmo
Thanks for the advice guys ;)
I'm just going to put together a quick 2 x 4 frame arount the car where it sits now & throw a tarp over it - instead of reinforcing the shed idea. I don't want to get to crazy on redoing the shed structure...I'll put down a couple sheets of plywood & get a torpedo heater...

Regarding the heater, should I get L.P. or kerosene fuel?

Thanks again :thumbup:

i have owned both and for the money kereosene to heats better and hotter and most rocket heaters will run atleast 6 -8 hours on one tank full depending on what size you get ...but with the heat loss i would get 155,000 btu and it will be toasty warm :thumbup: :thumbup:

woodmanscott@hotmail 01-27-2006 09:15 AM

tent idea
 
just a thought .. i used two swing set frames one at each end of the car and pulled the tarp tight and weighed it down with bricks that would be faster than building something .. just my opion


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