Panels in Exterior Door Question

[Kenneth Reidy]

Hi All,

I am in the design phase for a pair of shop doors. Right now, subject to change, the rails and stiles are solid wood with the upper panel being divided lights and the lower panel being wood. I have 2 concerned; one about water getting in the rabbet and panel movement. I was wondering if I made a composite lower panel if I could eliminate that movement and possibly mount it solid to the frame. My initial thought is to use thin (1/8”-3/16”) veneer glued to both faces of a plywood, HDO or some other composite board. I am open to any ideas since whatever route I go, much time and energy are going to be spent and I want doors to last. My shop is located in NM so we have severe temp changes with more than usual sun and occasional rain and snow. Hard on wood!

Many Thanks!

Ken

[Larry Edgerton]

Raised panel exterior doors that see sun are always a problem. We get 150 degree temp swings here too that have to be designed around and its tough. I have been wanting to try to incorporate Versatex into an exterior door for this reason but have not had tome to work on it. It would have to be a ridged exterior perimeter, the styles and rails with mouldings instead of cope and stick, and a way to make the plastic panels float. I was thinking a hidden foam gasket so the panel molds can float on the door frame as needed. I have done this on reproduction bay windows, the difference being that it is not a door, and it worked fine. Would have to be painted of course.

That Sun down there is brutal. I used to live in Kerrville Texas, and and worked in the Portales NM. area, froze my butt off every night, sweat every day.

Larry

[Kenneth Reidy]

Hi Larry,

Thanks for the input. Some time back I did three gates that had M+T wood frames and panels that were made of T&G PVC wainscot boards. This took care of the movement problem but the paint didn't hold up that well on the panels. I am wanting to finish these doors bright so I need to incorporate real wood. This is why I would like to use a hybrid panel design. Hope you are out of the wind.

Ken

[Tony Joyce]

One thing that can be done with panels is to use two panels back to back, with a thin ply or insulation between(loose not bonded). This will let the interior and exterior panels expand and contract at different rates. I have used this method with good success, but our temps are not quite as extreme.

Tony

[Kenneth Reidy]

Hi Tony,

If you were using a two panel system what would be the thickness of the plywood Vs the veneer? I am looking at a total panel thickness of approx. 3/4"-1" +/-. Would the plywood be 1/4" with a veneer of 1/8"-3/16"? Would cabinet grade plywood be the best substrake? Would it be possible to glue the panels directly to the door to keep water from entering the rabbet and traveling to the stile/rail joint?

Thanks,
Ken

[Larry Edgerton]

Kenneth

Versatex/Azek is not the same product as PVC T&G. It is an extruded cellular PVC, can be machined just like wood, and is available in thickness up to 1 1/4" from Versatex and 1" from Azek.

It holds paint extremely well. I use Sherwin Williams adhesion promoting primer followed by Grahams Ceramic and have stuff on Lake Michigan that has been there 15 years in that foul climate with no failures. Not sure what effect the New Mexico sun would have but I doubt it would be a problem any more than the norm. One consideration is the darker the paint the more heat it will absorb and the more it will move.

Heres a tip on painting regular PVC if you ever have to again. Go to a auto body supply and get a bit of adhesion promoting primer that is used on urethane bumpers and spray a light coat of that on first. It is designed to dig into the plastic and has some elasticity. Occasionally I use it on wood when it is going to be subjected to extreme use such as doors on a bar or very hard woods with a gloss clear.

Larry

[Tony Joyce]

I was referring to solid wood panels. I use 3/4" thick panels with 1/8" or 1/4" spacer of ply or insulation. 3/4"+1/4"+3/4"= 1-3/4" Properly finished and maintained they last for years with no problems. Bonding a solid wood panel to the stiles and rails of a door will create problems at some point. Wood will move and to a lesser degree plywood will also. Solid wood stile and rail panel doors have survived for many years if properly constructed and maintained. Mixing of materials(wood & plastic) sounds problematic, especially from a finish matching point unless painted. If they are painted why not use a PVC product entirely or metal doors?

After thought: You could use plywood for the panel, but it still should not be bonded to the stiles and rails.