Suitable Wood for Exterior Trimwork

Woodworkers list their top choices for wood species (and composite or synthetic materials) for architectural exterior trim details. June 29, 2008

I am a custom cabinetmaker who was asked by a customer to build 24" by 24" by 72" exterior driveway entrance stations. I never do exterior work but I figured I would use clear pine and prime the heck out of them. I had to use the pine because they were very detailed with crown and base moldings. I used Titebond 3 and stainless screws. I sprayed four coats of exterior paint on them and then installed them. After the first cold night and a little rain most of the joints opened up 1/8 of an inch. My question is, what is the best material to use (woods, glues and finish materials)?

Forum Responses
(Architectural Woodworking Forum)
From contributor L:
I would use Spanish cedar and West System Epoxy.

From contributor V:
Contributor L is right. That is what I would use, and make sure that it is dry too.

From contributor L:
You could also use White oak if you felt like torturing yourself with heavy lifting.

From contributor D:
Whatever you use be sure to treat\seal the endgrain as you assemble. A tree is a straw and will always perform as a straw.

From contributor J:
Mahogany is also good exterior wood.

From contributor F:
If the grain in your project is vertical and you then ran moldings around it horizontally the pine can swell up with moisture as much as 1/8 inch per foot, but the mouldings expansion will be perpendicular to the pine's. So the pine pushes the miters apart. Hope this helps.

From contributor B:
In order of preference (and cost):
South American mahogany
African mahogany
Western red cedar (not as hard though)
Spanish cedar (nasty dust odor issues)

You can also put sycamore in this list if available. I put Spanish cedar lower on the list only because we absolutely hate working with it. It is however being widely used now as an economical alternative and is supposed to have outstanding exterior characteristics.

From contributor L:
I call Spanish cedar "puke wood". It hasn't made me do it, but boy I'll tell ya I've come real close. It has outstanding outdoor qualities and is cheaper than pine.

From Gene Wengert, forum technical advisor:
Why not use pressure treated pine? This will last forever. Just be careful about the dust and its disposal. For exterior adhesives, TB II is a top choice along with PL-400 (an exterior construction adhesive).

From contributor P:
For any exterior project Ive done in the last five years Ive been using a PVC product called Azek. I love the stuff! It comes in sheets of 1/2", 3/4", 1" and you can special order it to 1 1/2" by 4x8 to 4x12.It glues well with a cellular latex PVC adhesive and it works easily with woodworking tools like router bits, saws, screws. It paints phenomenally with latex and holds up superbly.