Wood Panel gap on outside doors?

[Greatwhitewing]

Making garage doors (sliding barn type) from 2x8 pressure treated boards. A 1/2" thick PT plywood panel approx 48x71 inside the 2x8's that have a lap joint glued and screwed. Going to use 1/2" quarter rounds to hold the panel in place and allow for relative movement. The garage in in New England so quite a wide range of temps and humidity.

How much gap should allow for panel expansion? Currently it's dry and mild temps. The PT boards have been drying for several months clamped flat with spacers for air circulation.

Making four doors about 63" x 86" hanging from sliding barn door hardware rolling in a track.

 

[NUTTSGT]

I can't help you out with any info but I would like to see a build thread when you start making them.

 

[gonefirefighting]

just enough for you weather stripping is fine

 

[Jack Burton]

Making garage doors (sliding barn type) from 2x8 pressure treated boards. A 1/2" thick PT plywood panel approx 48x71 inside the 2x8's that have a lap joint glued and screwed. Going to use 1/2" quarter rounds to hold the panel in place and allow for relative movement. The garage in in New England so quite a wide range of temps and humidity.

How much gap should allow for panel expansion? Currently it's dry and mild temps. The PT boards have been drying for several months clamped flat with spacers for air circulation.

Making four doors about 63" x 86" hanging from sliding barn door hardware rolling in a track.

I'd wager about 3/16 all around. I wouldn't worry much about the ply but the way the crappy PT solid lumber is today, that's another story. If the solid decides to bow or twist, your quarter-round isn't gonna hold. Ideally you'd run a groove down the 2 x 8s with the 3/16 allowance and the quarter rounds would act as a concealer rather than a structural piece. I really think a frame that large without backbracing is gonna tweak on it's own without a middle rail or diagonal.

I'd look up articles on barn door construction.

 

[kbs2244]

When I built mine I didn’t worry that much about it.
I just used flexible caulk on the outside at the panel/frame joint..
I didn’t seal the inside at all, I just left it raw.

I am in N Illinois and never had any problems.
(I didn't use PT. Just a good coat of paint on regular construction wood.)

 

[Greatwhitewing]

I'd wager about 3/16 all around. I wouldn't worry much about the ply but the way the crappy PT solid lumber is today, that's another story. If the solid decides to bow or twist, your quarter-round isn't gonna hold. Ideally you'd run a groove down the 2 x 8s with the 3/16 allowance and the quarter rounds would act as a concealer rather than a structural piece. I really think a frame that large without backbracing is gonna tweak on it's own without a middle rail or diagonal.

I'd look up articles on barn door construction.

Took you advice to heart and made a change on the fly. I need flush on the inside so I routed a 1x1 groove for the panel and outside that a 1x.5 using plywood to retain the panel. I'll try to post up a sketch and take some pics later. Still busy building. Made some trim for the outside edge. Probably doesn't describe it well.

 

[djkeev]

Pressure treated wood is a horribly unstable product, shrinks twists and cracks almost uncontrolably!

Why are you using PT? It isn't a ground contact application, it is exposed to weather but that's why God invented paint! To protect raw wood from the effects of weather.

In my opinion it is a complete waste of time to construct a precision item, such as a door, out of pressure treated wood. Most often PT is a subgrade Southern Yellow Pine anyway, not a good cabinet wood.

If you are going to do this task on the cheap, at least use a good kiln dried Douglas Fir. Go to the lumber yard yourself and pick out the pieces of wood that are properly cut and straight!

Gaps on dry wood for a panel? 1/8" on all sides should be more than adequate.

Dave

 

[Greatwhitewing]

Pressure treated wood is a horribly unstable product, shrinks twists and cracks almost uncontrolably!

Why are you using PT? It isn't a ground contact application, it is exposed to weather but that's why God invented paint! To protect raw wood from the effects of weather.

In my opinion it is a complete waste of time to construct a precision item, such as a door, out of pressure treated wood. Most often PT is a subgrade Southern Yellow Pine anyway, not a good cabinet wood.

If you are going to do this task on the cheap, at least use a good kiln dried Douglas Fir. Go to the lumber yard yourself and pick out the pieces of wood that are properly cut and straight!

Gaps on dry wood for a panel? 1/8" on all sides should be more than adequate.

Dave

I have tried paint on kiln dryed wood and rotted out badly. This is a replacement project. The wood is not in contact with the ground but just above moist dirt and grass.

I dried the main stiles of the door for several months clamped flat with spacers to allow airflow between boards. They stayed quite flat and cut well whether it was routing or sawing. The new stuff I bought was of course quite wet. I used 2x6's PT to make some trim parts.

BTW doors are done now except for some adjusting of the rolling hardware.