Solar Lumber Drier - Part 4

[jteneyck]

Time to shingle the rof and make some doors.  I decided to put the shingles on myself, mostly because I needed to figure out how to incorporate a ridge vent with the clear plastic glazing on the front side.  Obvisouly, you can't nail into that stuff.  To get started I built some scaffolding. 

 



I had left about 3" between the top of the glazing and the ridge beam when I installed the glazing.  I ended up adding a 2 x 4 ripped at 45 deg on top of the ridge beam to get me up to the height of the peak of the rake trim boards.  Then I added a piece of 5/8" OSB wrapped on the outside with a piece of vinyl rake trim, and screwed that to the rafters above the glazing.  The front of it lays on top of the glazing, and I cut and fit pieces of closed cell foam in the valleys of the glazing up under that trim board to keep bugs from crawling in.  On the glazing side of the ridge beam no air will go up the ridge vent; I don't want it to.  On the shingled side, however, air will vent up through the soffits and out the ridge vent.  The insulation package below will keep heat in the building just like in typical house construction.  Here's a photo of what I'm talking about on the front side:



I used the same IKO architectural shingles like I used for the shed I built last year, with pretty much standard construction except I didn't use any ice shield.  I nailed on the drip edge, then the rake drip edges.  I used rolled starter shingle strips at both the eave and rakes, then nailed on the shingles.  There is a 1-1/2" vent slot in the OSB at the ridge beam, all but the last 9" or so on each end.  I used CobraVent for the ridge vent as it was convenient and about my cheapest option because I could buy it in individual pieces at my local HD.  I installed it in a rather unconventional way; I used screws.  I did that so that I could remove it if it didn't fit right. I biased the vent with more on the back of the roof than front so that the screws and subsequent shingle nails wouldn't hit the glazing under on the front side.  



The doors are just a 2 x 4 frame with the LP Smartside door cutout trimmed to fit.  I used gate hinges to hinge the doors, screwed on the outside. 





To fit the trim board over the hinges I routed a relief pocket on the back side.  All of the trim is installed with SS screws, so I can remove it if I ever have to service/change the hinges. 



 
The building is now pretty much weather tight.  Next up will be the interior buildout.  

John

[stav]

That is looking great.  

I do have a question about the placement of lumber. How are you going to get to the lumber that might be stacked at the front without needing to move everything that is stacked in the middle?  (Front being the short part and back being where the doors are in my perspective).

[jteneyck]

That is looking great.  

I do have a question about the placement of lumber. How are you going to get to the lumber that might be stacked at the front without needing to move everything that is stacked in the middle?  (Front being the short part and back being where the doors are in my perspective).

You aren't.  You load the lumber in even rows on stickers and it stays in the drier until the sample boards reach the moisture content you want.  At that point you can leave the wood in the drier, in a holding pattern, or you unload it.  Since the wood was stacked in layers on stickers the only way to unload it is one layer at time, back to front.  

John

[stav]

Ah, I see. So it is one batch at a time. You won’t cycle thinner boards out quicker than thicker ones from a particular batch.

[jteneyck]

Ah, I see. So it is one batch at a time. You won’t cycle thinner boards out quicker than thicker ones from a particular batch.

It's best not to mix thickness, or woods with vastly different drying rates.  If you do you have to dry so as not to exceed the max. drying rate for the thickest, slowest drying wood in the load to avoid checks, honeycomb, etc..  So if you have thinner stock in the load it's not going to dry much faster anyway.  

John

[ajkoontz]

I'm going to need a kiln like that at some point. Do you mind sharing how much you've got into it for materials (approximately)?

[jteneyck]

I'm going to need a kiln like that at some point. Do you mind sharing how much you've got into it for materials (approximately)?

Not at all.  I think I'm around $1800 right now, including the solar panels and fans.  It won't take much more, maybe two gallons of paint.  That's consistent with estimates I read for a couple of designs with 8 x 12' footprints.  I can post a detailed list of costs if you are interested.  

John

[Stwood_]

Lookin good................

[cputnam]

Do you have tables for drier time or just go by the wood itself with a meter - or both? What do you expect the difference to be between winter and summer?

[jteneyck]

Do you have tables for drier time or just go by the wood itself with a meter - or both?  What do you expect the difference to be between winter and summer?

The only table I've found is in the Virginia Tech. solar kiln documentation, and all it lists is the maximum drying rate/day for commonly dried species.  There are some general comments there and a few other places, most all of which tie back to Dr. Wengert who was involved with the design of the VT kiln, about operating the kiln but I haven't found any reference yet like you can find for commercial steam heated kilns.  The Forest Products Lab has tables by species and thickness listing the dry bulb and wet bulb temperatures you need at moisture contents from green down to KD.  I plan to try to follow the FPL dry bulb temps. as best the kiln will allow and by all means make sure I don't exceed the max. drying rate in the VT documentation.  To do that you use sample boards in the stack and weigh them daily.  Simple but effective.  

Winter will be much slower than Summer.  Even with an insulated building the internal temps. will not be nearly as high, especially at night, and when it's cloudy and snowing the whole load will cool off to about the same as the outside temp, so the drying time will be much, much longer. But even if it takes all Winter to dry a load it will still be better than what I have now with my air drying lumber stacks, which don't dry much at all from December to March.   


John