Decorative Trim with Stucco

Alternatives for wall detail trimwork on a stucco house, including coating options, wood choices, and plastic alternatives like cellular PVC. June 23, 2006

I am designing the facade of a house. The wall will be stucco finished. I want to add some horizontal detail to the wall to add a bit of color and emphasize the horizontal line. My thought is to use parallel wood strips about 2" high and maybe 1-1/2" deep with a slightly canted upper surface to keep rain from puddling. There would likely be 3 or 4 of these strips.

The facade has a southern/southwesterly exposure under long, low pitched 5'-6" eaves. This means direct sunlight only in winter and protection from all but the most wind-driven rain. The Locale is Portland, Oregon.

I want to aniline dye stain the strips. I think the strips will consist of three pieces laminated together - wider top and bottom layers in a brownish orange and a thin middle lamina in black. I am using natural and dyed maple extensively throughout the interior and thought I might use it here, though maple is not generally thought of as suitable for exterior finishes.

At any road, the wood must be fine grained, light colored and accept the dye stain reasonably well. Any advice on species selection, finish type and technique? Knowing the owner, maintenance is likely to be spotty, so minimizing maintenance is of first importance.

Forum Responses
(Architectural Woodworking Forum)
From contributor D:
Dyes are excellent, but I wouldn't use them for exterior applications. I did once on some doors and severe fading occurred within a couple of months. Go with something made for exterior purposes.

From contributor S:
Aniline dye will not last in your exterior situation - UV and moisture will degrade. This molding will be hard to re-dye or refinish with the stucco. Spotty maintenance? Sounds like a job for pigmented paint.

The best way to color wood (other than paint) is to use appropriate woods, period. Yellow Cedar, Western Red Cedar, Teak, Honduras Mahogany and a few others will give you some range of color, then they will have to be laminated with epoxy. Finish will then be problematic. We see Sikkens (the best of the lot) degrade in a year or less in the Midwest in south facing exposed faces. The woods above will then age to a silver gray.

If you wish wood, in a natural state, I'd suggest solid wood, milled for three levels to give depth and shadow. Use Teak or Honduras, and let it age naturally. No glue joints to fail, no compromising on colors (eventually there will be none), no maintenance.

From the original questioner:
Good advice. Though I've never attempted to use aniline dyed wood outside, I certainly have seen how quickly it fades in other media. Should have known better. I like the idea of milled features in solid wood. What range of colors does Honduras mahogany weather to? I really would like to avoid a wood that goes towards gray. Another thought I had was to cover a solid core of a suitable wood on 3 sides with Parklex 1000 from Finland Color Plywood Corp. This product is a pre-finished wood laminate over a composite core, and is designed for building cladding.

From contributor C:
If I understand your detail correctly, I believe whatever wood you decide to use must have caulk joints with backer rod wherever the wood comes in contact with the stucco (cement). If not, you are letting yourself in for a host of other problems - rot, water infiltration, mildew, to name a few. If I was going to do what I believe you want to, I would try first using an exterior product like Fypon or Azek. If it must be wood, don't use without taking the fermentation precautions.

From contributor S:
Lovely idea - "go faster" stripes for houses! The problem is that if you use two colours of timber laminated together, a colourless finish will not prevent the timber greying. Coloured finishes would be almost impossible, as it would mean masking up every time you maintain, and Sikkens Cetol 23 isn't that controllable. There is also the problem of re-painting the stucco without covering the timber. You could use the two-tone timber method, but plant the strips onto the stucco-ed wall with a lock-fastener system so they could be easily taken off to re-paint the stucco and to belt sand and re-coat the timber. I would then suggest ChemCraft D-Dur.

From contributor E:
Second the D-Dur suggestion. You can get UV inhibitor added to it and it can be tinted.

From the original questioner:
Thanks for all the advice! The stucco will have an integral color coat, so will not require repainting. I like Criag R's idea of using Azek or Fypon and then painting with standard paints for color - I'll probably settle for a single color rather than two tone stripes. (I wasn't aware of the cellular PVC products - thanks for turning me on to them.) This house has long eaves - 6' - 7-1/2'. I think the cellular PVC V-groove boards over plywood will make excellent soffit material. As most have pointed out, wood is going to be an ongoing maintenance headache, and it may well be difficult to achieve the effect I was striving for.