Q: My 18-year-old, two-story house has exterior stucco that is in good shape. But the doors and windows are trimmed in rough-sawn, painted one-by-fours, some of which have begun to rot.
Not only is the type of trim a bit dated, but it’s also beginning to affect the appearance of the house.
What are my alternatives for replacing the trim, and how do I make sure that I will have a good water barrier around the windows?
A: You must replace the rotted wood trim, but we think you should try to maintain the architectural integrity of the home.
We would replace the rotted trim with one-by-fours, but we wouldn’t necessarily go with rough-sawn boards, and we would consider dolling up the trim with “plant-ons,” a slang term for decorative molding applied to flat trim, giving the finished product a more interesting look. Whether you opt to create a new look or to modify the old, here’s how to do it:
First, thoroughly prime all four sides of the new trim. “Back-priming” reduces the risk of rot when water gets behind the trim. We would wager that the trim you are replacing wasn’t back-primed and this contributed to your needing to do this work now.
We like to apply two coats of primer, especially on the backside, which does not get a finish coat of paint.
Next, carefully remove the old trim boards. Do this gingerly. You didn’t tell us what type of windows you have, but if they are wood, avoid damaging them at all costs.
The best way we’ve found to remove trim is with an assortment of flat, stiff putty knives and flat bars. Score the paint at the joint where the trim attaches to the window or doorframe. Insert a putty knife in the joint and work it so the joint separates. Use gradually thicker bars and work the board away from the entire joint until the trim is removed.
Once you have all the trim removed, inspect the building paper that should have been applied between the sheeting and the stucco. We generally apply a new layer of building paper. No need to remove the old paper, just tack the new layer right over the old.
This special paper, called flashing, is available for use around doors and windows. It comes in a roll and measures about 6 inches wide.
Tack a strip of flashing on each side of the window, making sure to extend it 6 inches above the top of the opening. Place a strip of paper over the top of the opening, overlapping the flashing you’ve placed on each side. Working from bottom to top helps channel water away from the opening.
If you replace the trim with the same size material, the rest of the project is uncomplicated. Cut the trim to size and nail it into place.
A couple of things will ensure a waterproof seal. First is a liberal use of caulk. Apply two beads of caulk to the length of each board about an inch from the two long edges before you nail them in place.
Next, we strongly suggest you add a drip cap to the top trim piece. Look for 3/4-inch “Z” flashing. This type of flashing is made in the shape of a “Z.” One edge can be tucked under the stucco and extends over the upper edge of the trim.
If you opt to plant on a decorative piece, you may have to get the flashing custom-made at a sheet metal shop. The little extra cost is well worth it because it will extend the life of trim many years. Finally, make sure to caulk the joints where the trim meets the stucco.
If you decide to go with a different-width trim, you’ll have to do some stuccowork. Stucco patching is not difficult, but it does require some care, and there are a couple of tricks to make sure that your repair doesn’t look like a patch job.
It’s most important to avoid straight lines. Take a hammer to break and remove the stucco around the openings in an irregular pattern. Try to leave a couple of inches of the metal lathing exposed. Then apply new metal lathing with lathe nails, making sure that you intertwine the old lathe with the new. This will help the patch to become part of the old work and go a long way toward avoiding cracks.
Apply the trim, including the flashing as described above. If you choose a narrower trim, consider stucco molding. Stucco molding is milled with a groove on one side to accept stucco. It tends to be thicker, measuring approximately an inch thick.
Once the stucco dries, it’s time to paint. Raw stucco will never match stucco that has had several paint jobs over the years, so you have to help it along. We’ve had good luck building up the new stucco with concrete block coating and waterproofing sold in paint stores.
This material is the consistency of marshmallow creme and is water-based. A number of coats, feathered out to the old stucco, will blend the new with the old and give a seamless job.
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