Solar kiln build

[damato333]

It looks like I have to build a kiln. I know for uninsulated buildings there is no problems using green lumber. But a kiln needs to be insulated. So does anyone know if there is problems using green lumber when building a kiln. Can moisture get caught in the walls from the green lumber?

I want to build this.
https://pubs.ext.vt.edu/420/420-030/420-030_pdf.pdf

 

[Adamant]

Having read the document, I assume you could allow for this by only using the black rubber based coating on the internally facing walls and regular paint externally, I'd expect the green lumber would dry at a slowish rate since protected from the sun

 

[Adamant]

Sorry, stupid phone messing with me, not finished... Was going to say also, using the paper-backed insulation (as recommended) between studs should allow trapped moisture to wick out. I'll probably use corrugated iron on the exterior of mine if/when I build one and just not seal too perfectly at top and bottom ie well enough to stop vermin entry but not well enough to stop water/condensation exiting from wall space. You coul prob do the same using some spacers to allow a fine gap at bottom and/or top of exterior layer of ply. I doubt this would make much difference to the insulating property of the wall re the interior of the kiln itself. Just my opinion tho, being an expert in nothing

 

[damato333]

Are the fans mounted right up against the exhaust vents? In the finished kiln it looks like that is how they have it. But in one of the drawings it looks like there is a seperation between the back wall and the fans.

 

[betterbuilt]

Yeah it looks like they didn't do a good job explaining where the fans go in the drawing. I'd say this is good enough to go by.

 

[Marshy]

You could build the structure and let the lumber dry over the summer and then insulate it before winter next year. That might be enough time for the lumber to stabilize and dry. I wouldnt cover the lumber with any insulation until it has had time to dry otherwise it might mold.

 

[Adamant]

You could build the structure and let the lumber dry over the summer and then insulate it before winter next year. That might be enough time for the lumber to stabilize and dry. I wouldnt cover the lumber with any insulation until it has had time to dry otherwise it might mold.

That's probably better advice especially if using lumber prone to rot. I'd expect the kiln would still work uninsulated but perhaps not as controllable and depending on your environment, with greater heat fluctuation than desirable. Another option: the document recommends daily monitoring, so you could make the external ply openable / removable and incorporate some airing time for the framework while doing the daily monitoring

 

[Adamant]

Are the fans mounted right up against the exhaust vents? In the finished kiln it looks like that is how they have it. But in one of the drawings it looks like there is a seperation between the back wall and the fans.

This to force at least some of the air down over the front of the drying lumber and back between the boards for more even drying. The space behind allows the air to come back up and feed back thru the fans again. Not sure if the baffle/fans/fan supports wall runs completely from end wall to end wall but that is how I would do it anyway.