Simple boat shed with staging idea

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suntreader
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Simple boat shed with staging idea

Post by suntreader »

Hey group,

In the next two weeks I'll be putting up a shed around my Islander 32. The current plan for a 16' by 40' shed is as follows:

4x4 PT 12' on 8' centers as columns
Sole and top plates of 2x4
2x4 10' rafters reaching a peak of 14' at the center line, on 4' centers.
20' x 40' silver tarp to cover rafters.

No walls, its Florida and enclosing it would only make it hot. I would use the 'walls' to support staging 5' off the ground all the way around the boat, this would put the deck at belt height for most of the hull.

I'm wondering about how to anchor the structure. My first thought is to sink the columns 2' into the ground and set in concrete like a fence post. That creates all kinds of leveling problems though, much easier to build each side like a giant tilt up framed wall. I don't really want to pour a footing for a temporary structure like this, and guy wires would just get in the way. I could drive some 2x4 strakes into the ground and lag these to the columns but I don't know how much stability this would really provide.

Basically this will be a comfortable staging with a roof over head, 3' of space on each side of the boat, and a few feet forward and aft. A little wire and some ceramic bulb holders along the peak and it should be a real nice space!

It is pretty easy to get carried away with shed, I'm trying to keep it real, as they say. The boat is the project, not the shed. If I can get a roof overhead and some staging around with stairs up to deck level then I'm happy. Climbing that 6' ladder up and down a dozen times a day is getting old. I figure the lumber order will be under $400, the tarp was about $80, I've got the light fixtures I've been finding here and there, some left over wire from the garage rewire. I really like the look of the Stimson sheds, but I don't see how it could also support staging and I don't want to enclose the entire thing, just keep the rain off but let the breeze blow through.

Reuel Parker and George Buehler both have sheds like this outlined in their books, which is where the idea has come from. Anyone built one like this?

David
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Post by catamount »

I built a "tent" somewhat similar to what you are proposing. The process was detailed here: http://sailing.thorpeallen.net/Greyhawk/Year2/Tent/

On mine the spacing is 30", but I've got snow loads to worry about. Still 4' seems like a lot. I've anchored it to the ground with stakes on the diagonal struts, and by attaching the thing to some existing structures. My "tent" has withstood some pretty windy conditions, although it is fairly well protected from West and Northwest winds. We 'll see how it holds up to the Valentines Day Blizzard of 2007 (we're expecting about 2 feet of snow today!).

If you go the Pole Barn route, sinking the 4x4's into the ground, you could just make sure they are overly long, and then cut them off at the right height, rather than worry about trying to set them all to the same level when digging the holes and pouring the concrete.

Whatever you do, you'll want a lot of diagonal bracing.

Good Luck,

Tim
Last edited by catamount on Thu Apr 30, 2009 7:24 pm, edited 1 time in total.
Tim Allen -- 1980 Peterson 34 GREYHAWK
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Post by Tim »

I don't see any reason to bother with concrete in the holes. You could even get by without burying the posts in the ground at all, though it will make your whole rig much more stable and long-lasting (though I'd recommend burying them). But I'd forgo the concrete in any case--completely unnecessary, and a lot more work. Definitely set the poles overlong and then cut them off after they're plumbed; it's a fool's errand to try and make them all come out at the same height otherwise.

Diagonal and logitidinal bracings are key to your success. So is tightly securing the tarp on the top. Otherwise, keep your building as simple as possible, but don't skimp on the structure.

And don't forget that a 20x40 tarp is actually several inches smaller in each dimension thanks to the hemming, etc., so be sure to allow some leeway when you build the building frame--that is, make your frame smaller to ensure that the tarp will fit.
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Post by Figment »

Tim wrote: Diagonal and logitidinal bracings are key to your success. So is tightly securing the tarp on the top.
Can't stress the diagonal and longitudinal bracing points enough. CRITICAL.

As far as securing the tarp on top.... I'm not so sure about that. A roof with no walls beneath it is actually more suceptible to wind damage than a fully-enclosed shed. I'd want the tarp to be able to break away in a storm without damaging the structure or the boat in the process. Or make it really convenient to remove the tarp when you know a blow is on the way.

Tightly securing of course makes lots of sense, if only from a personal sanity standpoint of not subjecting oneself to the maddening noise of a fluttering tarp, but I think the severe weather must be factored into this.
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Post by Tim »

Figment wrote:
Tim wrote: Diagonal and logitidinal bracings are key to your success. So is tightly securing the tarp on the top.
Can't stress the diagonal and longitudinal bracing points enough. CRITICAL.

As far as securing the tarp on top.... I'm not so sure about that. A roof with no walls beneath it is actually more suceptible to wind damage than a fully-enclosed shed. I'd want the tarp to be able to break away in a storm without damaging the structure or the boat in the process. Or make it really convenient to remove the tarp when you know a blow is on the way.

Tightly securing of course makes lots of sense, if only from a personal sanity standpoint of not subjecting oneself to the maddening noise of a fluttering tarp, but I think the severe weather must be factored into this.
Those are good points that shouldn't be ignored. My point, which I didn't relay clearly enough, was more that if you don't secure the tarp tightly enough, it may collect water and sag between the supports if you get rain. It may not, too, depending on your overall design, but this seems likely if you have a horizontal tie piece at the top of the posts to support your rafters.

You'll have to take your own location and potential weather--as well as your sanity from a flapping tarp--into consideration when you determine how to secure it. You have a lot of trees and may be reasonably well sheltered from harmful winds.
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suntreader
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Post by suntreader »

Thanks for the advice. I will probably go ahead and have the rafters 24" o.c. rather than 48". I guess I need to bite the bullet and set the columns 2' into the ground. I mostly new I had to, just was trying to avoid digging all the holes.

The site is well sheltered with many large trees around but we can still have some pretty wild weather here in hurricane season. I'm not much worried about snow load, in fact if the snow loading becomes an issue I'll have bigger problems to worry about than getting a new tarp. With the side walls at 12' height and the peak at 14' that is only 2' of rise over about 10' of roof. Not much, but it really only needs to be enough to let the rain drain off.

I am worried about flapping and puddleing though. I will be attaching the tarp with rubber tie down straps at each grommet (every 3' along the edge) and I hope that is enough. If not then I'll have to come up with something else. There will be a horizontal tie piece at the top of the columns but the rafters will be on top of that with the soffit joining the end of the rafters out beyond the end of the tarp. I guess that is hard to picture, but the idea is that there won't be any structure perpendicular to the flow of water down the tarp directly in contact with the tarp. The 20' x 40' tarp is an uncut size, the size of the finished tarp is 19'6" x 39'6" so that would leave three inches on each side before the end rafters or the soffits are in the way. It will look a little odd since the tarp won't completely cover the roof structure but having the roof structure slightly wider and slightly longer than the tarp will mean there isn't a water damn a the edges either. Hard to picture, but pictures will follow in the next couple of weeks, whenever I start building the shed.

Even if enclosing it would make it more resistant to strong winds it would also make it unbearably hot most of the year here. I am in Florida after all.

As far as bracing goes, the staging will be basically be a deck build 5' up inside the shed and supported by the columns so that will add some stiffness, additionally cross bracing of the columns is planned and the end wall facing the street will be enclosed with board and batten stle siding to make it look a little less like there is an old boat hulking in the backyard, that is at the wife's request.

Dave
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Post by catamount »

I used battens of scrap lumber ripped to width (e.g. strapping) to secure the tarp to my rafters with screws. A lot more secure than tie-downs. Something to think about, anyhow.

Regards,
Tim Allen -- 1980 Peterson 34 GREYHAWK
Harborfields Housekeeping Cottages, West Boothbay Harbor, Maine
Sailors for the Sea, a new voice for ocean conservation
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Post by Tim »

Most of these sorts of structures require a bit of fine-tuning once you do the initial building, so don't worry about it if everything doesn't turn out just so immediately.

It sounds like you have a good plan for where you are, so built it and see what happens!
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