Sawmill Shelter

[nanook]

Have a Wood Mizer LT 28. Overall length is just under27'. Want to shelter it and am looking for options. Am thinking of 32' x 12' x 8'(h)building with roof with hatch at back to get rid of sawdust and large door in brow side with 16' (?)opening. Mill could probably be manouvered into that size opening and later remover if wew and to use it elsewhere. Although it is portable we will probably leave it set up in this permanent location.

[Dave Shepard]

Welcome nanook! There is a discussion HERE about building a shed for a Woodmizer LT40, which is the same size as your LT28.


Dave

[nanook]

Thanks for the lead and reply. Seems most people have much "grander" visions of mill shelters.

[Dave Shepard]

I guess it depends on how much you are going to be sawing, and what your weather conditions are like. Personally a roof is most important, I wouldn't want to have to shovel two feet of snow off the mill all winter long.  I see you mentioned an 8' high building, I think you will need at least 10' if not more for the motor to clear when the head is raised all the way up.


Dave

[Don P]

I was thinking about the orientation of the 16' opening. If it is on a gable end then it is supporting little weight and doesn't need to be framed very heavily. If it is on an eave side it is supporting half the weight of that 16' section of roof and needs to be framed over a beam capable of supporting that weight over a fairly long span. I threw some numbers at it real quick to demonstrate, I'm sure they are off. I assumed 70 pounds of snow per square foot on the roof. Half the width is 6'(I neglected overhang, wrong)X16' spanX70psf(I neglected weight of framing,wrong)=6720 lbs. Comparing that to a beam made up of 4- 2x12's of fair strength it just passed.

Mainly it was just to show that supporting a roof on a long header takes a larger beam than most people realize, the actual numbers are probably off a good bit. There's more than one way to make that door header. My shed is similar to what you described and is supported on a single 2x12 of sycamore that has held up just fine, but we don't have much of a snow load. There are 2 long headers on our place that I put props under if we have a big snow coming. When I half the span like that the header is 4 times as strong.

If you enter the gable the roof load is supported on the sidewalls which can then have supports much closer together than 16'. At 32 wide that would be trusses most likely. It would look kinda different to have a building 32' wide and only 12' deep, so there's something to think about, it would be much taller at the peak also. It would allow for easier expansion. Just kicking around what I was ruminating as I read 

[tcsmpsi]

There are lots of options and methods.  And lots of discussions and photos in the forum.

I'll post a couple shots of mine and there are other pics in my gallery in various stages of production.

Might get an idea or two to go by. 





That's a 20' opening on the feed side.

[bedway]

tcsmpsi,,,what is carrying your load over the twenty foot opening,,header??,,,,,,bedway

[brdmkr]

Tcmpsi

I notice that bedway just posted.  I have a similar question.  Are your rafters 2x6 over the mill and then stepped down to 2x4 in the back?



Also, you want to come to GA and help me build one?

[Snag]

Looks like the diagonals help to greatly reduce the necessary header dimension.

Bedway - keep in mind, tcsmpsi is in texas and you and I need beef-up our designs for our snow loads.

[tcsmpsi]

Snag is correct, bedway.  I don't have much of a roof load, and the diagonals are spaced/angled to carry quite a bit.  It would easily carry any of the snows I've ever seen around the area.   It is a 2X10, with a 2X4 attached to the top (all crowns up, of course, and good, clear wood) to give it a little more stiffness and to give my rafters more of a seat.

brdmkr,
Yes, you saw correctly.   ;D  And, it would be my pleasure to come to GA and help you build one.  And to help you with your Briggs.  All you have to do, is figure how to get all this stuff here tooken care of.   :D

And, by the way, nanook, it is at least 10' clearance for the mill and handling area. 

[mike_van]

Here's a [small] pic of what I built for my mill some 15 years ago - The long opening is 18', the header is 4  2x12x18' oak planks I sawed on the mill, 2 of them are full length, others are staggered & double bolted every 2'.   4x8 rafters, [oak], 4' centers, with 2x4 oak purlins running across them to screw the roof to.  It's had 30" of snow on it, 'till it slid off, 7" pitch on the roof.  Elephants could dance on this roof, [till they slipped & fell off]   

[brdmkr]

S
brdmkr,
Yes, you saw correctly.   ;D  And, it would be my pleasure to come to GA and help you build one.  And to help you with your Briggs.  All you have to do, is figure how to get all this stuff here tooken care of.   :D

I like the way your shed steps down in the back.  I may just have to copy your design.  I imagine it will be plenty stiff enough for me as we likely get about the same amount of snow ;)

I got the Briggs running like a champ.  The needle slipped off of the float (likely as I was installing).

If you ever get caught up our your way, come on over and visit for a spell.

[DR Buck]

Am thinking of 32' x 12' x 8'(h)building

8 foot isn't going to be high enough!        Raise the head all the way up and measure up from the ground.  That's what you need for overhead clearance.    I think you need close to 9 ft jst to get in the door with it in the travel/stow configuration.

[PineNut]

I am looking at a shed and my Cookssaw needs a minimum of 11 ft vertical clearance. Also I am looking at a 22 ft minimum opening on the side. Present plans for the bean over the opening are three 2 x 8 wide and two 2 x 8 high with ¾ plywood between for a finished beam of 7 ½ x 16 with diagonal bracing extending out about 3 to 4 ft from the post.

[beenthere]

Trying to picture that beam, but it's not happening.  Drawing a blank..

Are the three 2x8's on edge, as well as the two 2x8's?

The finished dimension of 16" is made up of ??
and is this the depth of the beam?

The 7½" dimension is made up of ??
and is this the width of the beam?

Is the plywood used as a web like in an I-beam?

[Furby]

BT, it'll be made up of a total of 6-2"x8" in three stacks with a layer of plywood sandwiched between each stack.

[Sprucegum]

The way I read it there are 6  2x8's in total positioned 3 wide and 2 high, all on edge. There will be 2 pieces of plywood sandwiched vertically like so

 I|I|I
 I|I|I  with no gap in the ply from top to bottom

[brdmkr]

Are there any rules of thumb for how much strength reduction occurs when you build up a beam like this (stacking boards on edge) as opposed to using a single whide board?  For example, what is the difference in strength between 4 2x6s with plywood between relative to 2 2x12s with plywood between?

[Don P]

I'll let you know when and if the plywood association responds, waiting on an email back  ;)

I can throw a little into the mix to think about on the braces. If a beam goes under full load and starts to bend, the braces will take the load first. I think we were talking about roughly 6000 lbs on the beam earlier so #3000 for each brace vertically. Assuming the braces are at 45 degree angles the load along their axis becomes 1.414 x #3000. This is the connection design strength needed if you are counting on the braces supporting the beam. A nail in shear is good for around 100 lbs.

[Radar67]

Here is a copy of the APA booklet on plywood beams I used when I built my shed. It has the loads listed for the different designs.

Stew

[Don P]

I was throwing something different into the question this time. I asked for design guidance for lumber/plywood beams with discontinuous chords (We all want a beam longer than the longest log we can saw)

This came back;
Unfortunately we do not know of any design guides for field assembled beams that use non continuous cords.


this might be something we as a group could hire an engineer to design. It wouldn't be a bad idea to have the entire portal engineered. We've been talking about gravity loads only. If the roof has a load of snow and the wind blows those braced posts are going to be taking quite a load. If that entire wall was designed for several snow/wind combinations we could have a good standard, buildable design to point to when people asked. or maybe a sponsor could have engineered plans for their mill's shed posted.

[Warren]

Don P,

When you say "discontinuous chords", are you referring to a header which is wider (longer) than the longest piece of framing lumber laminated together behind the plywood ?

If so, one of the websites referenced in last year's discussion of plywood headers had a picture of what I "think" you are describing. I can not remember if it was the U of Iowa, U of Nebraska, or Canadian website that had the picture.  The basic premise was two layers of  3/4" plywood on each side of the header. Stagger the plywood joints on 4 ft centers.  The framing lumber "chords" behind the plywood were staggeered on 2 ft centers between the plywood joints on both layers.  Everything was screwed and glued on a 3" or 4" interval on each layer to each chord. 

My recollection was that there was a lot of material cost involved.  I eventually found metal trusses for less cost / effort...   Sorry I can not remember the exact website. But I got to it by surfing the links in the previous  FF thread...

Warren

[brdmkr]

Stew,

Thanks for that post.  It was very helpful 8).  I did notice where it said that calculations were based on full-length flange lumber.  I am needing a 20ft span, so I can cut logs that long without too much trouble.  Now, all I need is to finish everything else I haven't finished, so I can get started on something else to get me behind ;D

[chet]

This is how I solved da header problem on my sawshed. It has survived 6' of snow load with flyin' colors.  ;)

[brdmkr]

Chet,

What are the deminisons of the lumber you used?  Also. what kind of span are you dealing with?

Thanks,