Entry Door Materials
Iíve personally never seen mahogany rot and its wonderful for staying straight. I been experimenting with lyptus as a lower cost material similar to mahogany, but the jury is still out on it. Keep in mind that it is heavy to work with and hard on knives.
From contributor T:
Itís my experience that any exterior door, regardless of how or from what wood its made, if not under some type of cover (awning, porch roof, etc) will deteriorate in time. Maple works well for paint doors, as does poplar, of course so will fir and pine. Again, the main issue for lasting exterior doors (especially paint) is keeping them guarded somehow. Even if itís a glass storm door, which of course hides the beauty of the door you built, but better than leaving it exposed. This concerns not only the door but its trim out and jams as well.
From contributor G:
I agree with Contributor D. Exterior doors must be protected from the elements. How about Cypress? I never used it, but I've heard it's pretty good. I also agree with Contributor H. Mahogany is a great choice for exterior doors. Itís a very stable wood, and very tough, but even it needs to be sheltered from the sun and rain. Thatís why the front porch was invented - not to protect you from the weather, but your door.
From contributor S:
To contributor G: The porch was invented because the dry panel door was invented. If you make a window or a glazed door, you use a mastic or sealant when you put the glass in. When you make a paneled door, do you set the panel in sealant? Of course you don't! You rely on the paint/varnish/exterior stain to seal the gap.
My advice is to get the primer on all available surfaces before assembling the door. Bed the panels in acrylic caulk (don't use silicone for obvious reasons) when you assemble the door, then paint all surfaces. If the door is to be stained, apply the basecoat (Cetol 1 or similar) before assembly, use a brown caulk for minimizing color grin, then apply the finishing coats to all available surfaces, especially tops and bottoms.
From contributor D:
Make the door thicker than you think it should be - 2-1/4 min. When people say mahogany, they should be saying Honduras mahogany. Poplar is the absolute worst. Maple is not much better (soft or hard). White Oak is good.
We like solids, but remember any core you use could become the weak link, bond-wise. Use long tenons, fully coped and stuck with integral profiles (no tacky moldings), and make the panel joinery wide and tight. Any glass needs proper sealants/clearance. Upgrade all the hardware, especially the hinges. Upsize the jamb and plan on cutting in a W Oak sill into the sub-floor and bandboard. Plan now for weather-strip.
The talk about overhangs is correct, but you usually aren't consulted about that, so have no control. Use the proper glues and don't believe all you hear about water resistant. Check the finishing forum for a horror story on finishing exterior entry.
Doors are the most difficult, problem prone articles of wood other than boats. Unlike boats, when a door fails, they call you. Boats sink with their owners. Both (doors and boats) require periodic maintenance based upon exposure and environment. Professionals need to be involved. If it is your own door and you are willing to put up with any shortcomings, fine. If it is for hire, consider your liability and responsibility.
From contributor C:
Ninety-nine percent of the exterior paint grade doors made by millwork companies here in the northeast are pine or fir. They are generally stave core/laminated to keep shrink/expansion to a minimum, as well as to forestall warping by mixing grain.
Mahogany and oak make poor paint grade doors because they have open grain, and do not paint to a smooth surface. Cypress is specified occasionally these days because it is very rot resistant, but it doesn't paint all that well. Poplar paints and machines well, but it is very susceptible to rot. Never use it outside. I've encountered white or red cedar doors occasionally and they are extremely rot resistant, and paint beautifully if you seal the tannic acid in the wood from bleeding into the finish.
Oak is very strong, wear and rot resistant, and is customarily used for the threshold. It is often simply sealed with boiled linseed oil, or painted black. The advice to prime the panels before assembly is wise. There are many silicone modified latex (acrylic) caulks available that will accept paint. Never use pure silicone caulks.
Paint is essentially 100% UV and water resistant. If the coating is kept in reasonably good repair, (repaint every 4-6 years) the door will last ages. I have worked on scores of painted exterior doors over two hundred years old, still in good shape.
Doors always last longer if the finish on both sides is the same, (not paint inside and varnish outside) and you paint the top, bottom, hinge butts, mortises, etc. as well. Even if the finish paint specified is latex (or acrylic,) prime it with exterior alkyd primer.
From contributor B:
Pine, fir, and mahogany are all suitable woods for paint grade. I always stave my paint grade doors. It's a little time consuming; however I maximize the use of my materials. The only time I laminate after staving is for stain grade doors. I have never had a problem seeing the laminations, or grain changes, through the staving. I use West System Epoxy for my glue ups of exterior doors.
From contributor G:
To contributor S: I don't think they had mastic or sealant as such in the 16th century. These old doors that are hundreds of years old were well protected from the elements. I do not feel yellow poplar would be a wise choice for an exterior door, but I must add that I have torn poplar siding that was painted off 100 year old houses that was rot free and hard as a brick.
From contributor K
I have a question about building an exterior door. When gluing two boards together that are cross-grain glue up, how do you allow for wood movement during temperature changes so that the wood doesn't split, when the board is 8 to 10 inches wide? Should you glue the whole joint or just the center portion? Does anyone have any advice?
From contributor G:
A mortise and tennon or cope and stick, on a door, are long grain to long grain. When gluing up wood, long grain to long grain, no jointing is necessary. The portions of the joint that are end grain to end grain do not hold well, but should also be glued. The cope and stick is like a mini
mortise and tennon. If the rails are nice and wide, then dowel rods or other additional jointing is not necessary. The rails must be of sufficient width to properly hold the door together with modern types of glue.
The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).
Comment from contributor A:
On core: we use a pine core made in Idaho. It is light and sturdy. The ends of the short pieces are not finger jointed, but staggered. Warpage is a rare issue. That stave core reduces expansion and contraction is a myth. Example: If you make poplar stave core, it will behave as solid poplar on the volumetric parameter. It will however resist warp and twist due to the multiple glue interfaces. From a production stand point, we use stave core for two reasons. One for the resistance to twist and warp, the other for the reduction in hardwood used to build a door. You'll have to weigh in your labor costs on the process to see if it is economical on short runs.
On tenons: I have been using Freeborn stacked cutters forever. Standard on a 2 1/4" door is a 3/4" deep x 1" thick tenon, regardless of the pattern. I use Franklins Titebond Original, and have never had a door fail.
Comment from contributor B:
We're constantly dealing with custom exterior doors, from large barn style doors to entry doors and everything in between, including seasonal pool house doors. My favorite wood is Spanish cedar. It does have an open grain similar to mahogany, but itís very stable and extremely rot resistant. It paints beautifully since itís softer and lighter than maple oak or mahogany, but definitely harder than white cedar and most western red cedar. If using a core, I recommend Timberstrand, but my favorite is solid styles and rails tenon and mortised together. (The cost of this door material and style is almost more expensive than any other). On another note; I have seen laminated basswood cores do very well in very wet areas, but they were custom made.
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