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Kiln Doors and Large Span OPening

Started by PA_Walnut, April 23, 2018, 06:42:14 AM

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PA_Walnut

Progressing along on my kiln chamber build. Super-insulated slab is down, epoxy on concrete cured. So, let the framing begin!

My chamber is 22' long and I intend to load it from the side (not end). Thus, I need two 10' doors.

Would appreciate some wisdom from those who've gone before me:

1. Other than Nyle's plans for construction/insulation, and tips on hinges and gaskets...that last?

2. Since I need a 21' clear span on loading side, and tips for what to use to frame/span that far? I have some oak that I could saw into some silly-sized beams, perhaps an LVL, or man-up for a steel I beam. Again, I know all will work at some degree, but looking for some words of wisdom from those who've walked the path ahead of me!  :D

Thanks. Will post some pix along the way.
I own my own small piece of the world on an 8 acre plot on the side of a mountain with walnut, hickory, ash and spruce.
LT40HD Wide 35HP Diesel
Peterson Dedicated Wide Slabber
Kubota M62 Tractor/Backhoe
WoodMizer KD250 Kiln
Northland 800 Kiln

Don P

Parallel chord trusses are another option. Is the header supporting anything (are the doors swinging on the side posts), just supporting the doors (track), or is it supporting some section of roof and doors? Need more info, like a sketch, or you need to determine load and allowable deflection.

PA_Walnut

Just a 10x22 box (shed) with the two 10' doors along the front, attached to the corners. Design is per Nyle's instructions, but they do not mention the clear-span details. I'll make a sketch if it helps.
Thx
I own my own small piece of the world on an 8 acre plot on the side of a mountain with walnut, hickory, ash and spruce.
LT40HD Wide 35HP Diesel
Peterson Dedicated Wide Slabber
Kubota M62 Tractor/Backhoe
WoodMizer KD250 Kiln
Northland 800 Kiln

YellowHammer

With a box kiln it's all about the stability of the doors to maintain the door seals,  assuming as Don mentions that the door header isn't load bearing which I built mine so it wasn't.  Ready made trusses would be fast for framing.
If I was going to build what you are doing, I would go out of the box a little and build the opening for the doors as well as the door frames out of welded steel or aluminum and use the weld on security gate hinges with grease fittings. I'd make it a premade structure welded flat on the ground, corner braced and then attach it to the wooden building as a big door unit.  It would be difficult but would never sag or degrade with some proper paint.  I've got the setup on our security gate and it's been working for years with an 18 foot swing gate. With big doors the issue is door jamb strength, hinge strength, and door stability, holding the doors out in space through all the thermal cycles.  The other key whether built from wood or steel is to build the doors as light as possible with wood or light and stiff with steel.  The less they weigh the less they will sag.
It will be easy to build something that will work for a short term me, much more problematic to build one that will last for a decade.  
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

Bruno of NH

On the clear span you could always put a temporary adjustable post in the middle and take it out when loading and uloading.
When in place it could help seal the doors in the center
Just my 2 cents
Lt 40 wide with 38hp gas and command controls , F350 4x4 dump and lot of contracting tools

firefighter ontheside

I think I would build a flitch beam if you can get a piece of steel that long.  Say a piece 12" wide by 1/2" thick and sandwich it between two 2x12s.
Woodmizer LT15
Kubota Grand L4200
Stihl 025, MS261 and MS362
2017 F350 Diesel 4WD
Kawasaki Mule 4010
1998 Dodge 3500 Flatbed

scsmith42

I built parallel chord trusses for my 20 foot openings.  Thus far (2 years) it's worked well.

The chord was around 4' tall.  
Peterson 10" WPF with 65' of track
Smith - Gallagher dedicated slabber
Tom's 3638D Baker band mill
and a mix of log handling heavy equipment.

Don P

I'm guessing about a foot of overhang on the roof so 6' of roof x 21' bearing on the header 126sf x whatever your snow+ material load is, probably in the neighborhood of a couple of tons up top. The trouble I see is that 6" end post trying to restrain racking from the 10' door hanging from it. That calls for a welded moment resisting frame, a steel post welded to a steel header or a large steel L bracket firmly connecting that joint. If it were a flitch plate header you could make the post the same way and weld the connection between the post and header plates. Flitch plates are not the most efficient use of steel though, the same weight in an I shape is stronger and stiffer. Steel parallel chord and steel post might be worth exploring. Steel fabricating plays into that efficiency cost equation too though.

YellowHammer

Might could use door mounted castor wheels mounted to the free ends of the doors to roll on the concrete apron when they are opened, and to support them when they are closed.

YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

PA_Walnut

What kinda monster have I created!?  :o ;D

I like Yellow's idea of steel frame, but I don't have any idea what size it would take for a 20' span.

What if I were to do a "flitch beam" with a LAM and steel for the long span, then do as Yellow suggests and build a welded steel frame to insert into the opening, much like a commercial metal door.

There's a metal fab shop about 1 mile from me that does custom work. I could get them to build whatever I want (and can afford) I suppose.

Anyone have any pix/plans/sketches as food for thought?

Thx

ps. Would a 3.5 x 1.5 x 1/4" inch steel box tubing frame works a frame, ok to span? Since I'm planning 2x4 construction, per Nyle's plans, it would be mighty convenient. Steel costs looks like about $500. Could do the doors in aluminum to save weight, at a cost of about $1200-1300 materials.
I own my own small piece of the world on an 8 acre plot on the side of a mountain with walnut, hickory, ash and spruce.
LT40HD Wide 35HP Diesel
Peterson Dedicated Wide Slabber
Kubota M62 Tractor/Backhoe
WoodMizer KD250 Kiln
Northland 800 Kiln

Don P

I like the idea of Scott's truss. A steel truss with steel posts, might be able to simply span it with pan deck from that header to the back wall without further framing... the steel shop should be able to design and quote any or all of that.

Josef

Not sure if you have a metal building contractor nearby, but you might look at a pair of "C" or "Z" purlins sandwiched to make a beam. I used two 12 ga 8 inch "Z" purlins boxed with 2x8's between to form a box beam for my solar kiln to frame the doorway. Pics are in my gallery. The steel purlins were left over from a steel frame building that was engineered for NW PA, 10 lb dead load and 50 lb live load over a 25 ft span on 5 ft spacing, so spanning a 20 foot opening was easy. It was a few years ago that I bought them, but I think they were about a dollar a foot surplus.

Joe
In my house I'm the boss, I know this because my wife said so, I only hope she doesn't change her mind!

New to me Timber Harvester that I'm learning to operate, been building a home built mill for a while, should be ready to make sawdust with it someday if I ever quit "modifying" the design.

YellowHammer

If the peak of the kiln roof is centered over the door then the door header won't be load bearing, and a simple gable truss can be used to support the roof over the front door opening.  Simple wooden 2x4 trusses can free span 32 feet with no problem.

The door frame and supports would be independent of the trusses.      

The main load on the door frame will be the verticals where the hinges attach, which need to be stabilized to prevent the door from sagging.  

Also, since the door seals by Nyle are face seals, the door jambs need to be wider than the doors so that the seals can be attached to impact the inside door skin.  For example, if the doors were 2x4 thick, the door frame would need to be made from 2x6 stock. 
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

Southside

Just curious - why did you give up on the container kiln plan?
Franklin buncher and skidder
JD Processor
Woodmizer LT Super 70 and LT35 sawmill, KD250 kiln, BMS 250 sharpener and setter
Riehl Edger
Woodmaster 725 and 4000 planner and moulder
Enough cows to ensure there is no spare time.
White Oak Meadows

PA_Walnut

Quote from: Southside logger on April 24, 2018, 11:43:28 PMJust curious - why did you give up on the container kiln plan?


Two primary reasons were space and aesthetic. I need to load from the long side, plus since we want to make our buildings all look pretty (part of the overall design), decided to do traditional. PLUS, when I grow weary, it will make a MIGHTY nice man-cave building! :D
I own my own small piece of the world on an 8 acre plot on the side of a mountain with walnut, hickory, ash and spruce.
LT40HD Wide 35HP Diesel
Peterson Dedicated Wide Slabber
Kubota M62 Tractor/Backhoe
WoodMizer KD250 Kiln
Northland 800 Kiln

GeneWengert-WoodDoc

Perhaps a visit to several local farms with barns, especially old barns, will give you some useful ideas.  They do make hinges for large doors.

For gaskets, you could use old fire hose that looks like fabric.  Very effective.  The local fire department will appreciate the new hose that you bought for them to replace their old hose.

One issue, with using metal frames and doors with large spans in a kiln, is that when the kiln heats up, the metal expands, while the rest of the wall, if masonry or wood, does not.  This creates cracks, as something has to give when the door frame expands.
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

Bruno of NH

You could also make your door frames out of heavy gauge metal framing.
3 5/8" it can be welded together and made very strong and can be purchased very reasonable. 
I have seen some things made with it.
Lt 40 wide with 38hp gas and command controls , F350 4x4 dump and lot of contracting tools

Southside

Yea - the big metal box is ugly, but I am going to wrap it with some board and batten and frame in a couple of old windows that I have so from 20' away it will look like a building.  
Franklin buncher and skidder
JD Processor
Woodmizer LT Super 70 and LT35 sawmill, KD250 kiln, BMS 250 sharpener and setter
Riehl Edger
Woodmaster 725 and 4000 planner and moulder
Enough cows to ensure there is no spare time.
White Oak Meadows

YellowHammer

YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

PA_Walnut

Great stuff! Yellow, do you have a pic of your building you could share?
I'd like to see your front, non-load-bearing wall!
Thanks.
I own my own small piece of the world on an 8 acre plot on the side of a mountain with walnut, hickory, ash and spruce.
LT40HD Wide 35HP Diesel
Peterson Dedicated Wide Slabber
Kubota M62 Tractor/Backhoe
WoodMizer KD250 Kiln
Northland 800 Kiln

Don P

The problem with either is really that unbraced portal frame. If you could run out to say 24' and have a 4' solid wall section that houses a tool or equipment room at one end that would go a long ways towards bracing the opening. A bracing wall at both ends even better.

This is another way to build a braced opening with narrow sidewall sections;
http://www.anthonyforest.com/assets/pdf/apa/glulam/Tech_Topics_A_Portal_Frame.pdf

longtime lurker

One of mine has an opening that size. I used a flitch beam comprising two 12x2's and 1/4" corten plate. Its way overkill... after the kiln falls over i think ill use it for a bridge girder.

My door is built on 3" aluminium RHS frame with a fair bit of cross bracing for strength without excessive weight, ½"marine ply skins, foam filled. Due to a breakdown of the other unit he kiln was commissioned before i got to hinge the door (plan A had big hinges one side and a support wheel for the far end. The single big door rather than two smaller ones was to get a better seal) so I just lifted the door into place with the forklift and cranked her up.

2 years later I still lift the door into place with a forklift: It's not much slower then swinging doors would be without the footprint of a swinging door, it seals like a bottle, and if it aint broke dont fix it.

Honestly I'd talk to some coldroom installation guys - they can probably do a nice lightweight SIP panel door with a good seal for half the price of building your own and you'll get a better job.
The quickest way to make a million dollars with a sawmill is to start with two million.

YellowHammer

 I have a couple pics.
With the gable directly over the door, it is a free span structure, non load bearing.  I constructed the beefy doorframe header not for the roof strength, but as a top brace and anchor for the top end of the side door jams, which is where the hinges attach to the building.  It must be very strong or the weight of the cantilevered doors will cause sagging.  I put a half a dozen hinges on each door, and it still has some give.  The doors are constructed as lightweight as possible, with the foam insulation, and are stiffened using glue and screws and plywood.  I screwed the sill into the concrete.

 

Notice the face seals on the doors on the door frame, and matching foam on the doors for them to seal.  








YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

scsmith42

Quote from: Don P on April 24, 2018, 05:58:42 PM
I like the idea of Scott's truss. A steel truss with steel posts, might be able to simply span it with pan deck from that header to the back wall without further framing... the steel shop should be able to design and quote any or all of that.
Here is how mine is designed.  

The bottom is comprised of three 2x12's sandwiched together (and glued).  The parallel chord truss above is glued with construction adhesive and screwed to the 2x12's.  It is a 20' span.

Not shown in the photo is the 1/2" plywood that was attached in full sheets covering the 2x12's and truss.  It too was glued well and nailed close.  For that matter, all of the exterior plywood was glued and nailed.  I did this in order minimize racking in all directions and to add a lot of shear strength.

Finally, on the inside the truss was filled with closed cell spray foam, as was the rest of the kiln walls and floor.

No issues with sagging at all.

On a side note, the kiln is designed for 2000 bd ft of 4/4 oak in two stacks side by side 4' deep, 8.5" wide and stacked 30 layers high with 3/4" stickers 18" on center.

Peterson 10" WPF with 65' of track
Smith - Gallagher dedicated slabber
Tom's 3638D Baker band mill
and a mix of log handling heavy equipment.

PA_Walnut

Quote from: scsmith42 on April 27, 2018, 05:25:38 PMHere is how mine is designed.   The bottom is comprised of three 2x12's sandwiched together (and glued).  The parallel chord truss above is glued with construction adhesive and screwed to the 2x12's.  It is a 20' span


This is awesome and very helpful! Thanks much! That would seem to be a design that would work well for me and and aesthetic that I can get past the War Dept.

A few questions, if I may:


  • Are the 2x12 headers all single-board spans? (the pic looks like the front one is two pieces)?
  • Is the chord truss engineered design (is there a spec for it) or did you just make it to what you thought was right?
  • The sides are of concern as elaborated above. Can you outline that a little too? I'm assuming that it's more 2x12's stacked and glued?
  • What is your front opening height and how high is the total structure in the front?

Thanks for your efforts and picture posting!

I think this design with Yellow's idea of a metal door frame is what I'll do.
I own my own small piece of the world on an 8 acre plot on the side of a mountain with walnut, hickory, ash and spruce.
LT40HD Wide 35HP Diesel
Peterson Dedicated Wide Slabber
Kubota M62 Tractor/Backhoe
WoodMizer KD250 Kiln
Northland 800 Kiln

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