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  • Writer's pictureJessica Foster

Exterior Trim: Why Does it Matter and What Can Go Wrong?

We’ve established that a building’s exterior is more than just aesthetic in our previous blog. The exterior serves as a defense between a home’s vulnerabile inside and the elements, making a functioning exterior a crucial component in any project. An additional part to a home’s siding is the exterior trim, which is defined as the material that edges a home’s doors, windows, lower edge of the roof,and beneath the roof. An exterior trim not only serves to create visual boundaries on a home for aesthetic purposes, but also helps deflect rainwater away from windows and doors. As such, it’s important that the exterior trim is properly maintained. The National Association of Home Builders (NAHB) has guidelines in place to help achieve this.

One issue that may be observed is gaps in the exterior trim. According to performance guidelines, joints between certain exterior trim components, such as siding, should not be wider than ¼ inch. If wider, these joints must be fixed. There also might be situations where the exterior trim board is split. Performance guidelines state that splits wider than ⅛ inch and longer than 1 inch are excessive and must be repaired. Fixing splits can be achieved through using certain fillers.

Like exterior siding, the exterior trim board can end up bowed or twisted. Materials such as wood tend to naturally bow and twist over time, so minimal bowing and/or twisting shouldn’t be of concern. However, if the exterior trim board bows and twists in excess of ⅜ inch in 8 feet, it is considered excessive. Repair can be accomplished through refastening the offending boards, or by replacing them completely.

Lastly, exterior trim boards may end up cupped. Cups exceeding 3/16 inch in 5 ½ inches are considered excessive. Similar to trim boards bowing and twisting, cups are quite common and don’t immediately need repair. Understanding what is and isn’t tolerable is crucial to avoid unnecessary repairs, as minimal cupping is to be expected. When the cupping is excessive, it can be rectified by the aforementioned method of refastening the trim boards or replacing them.

Like siding, a home’s exterior trim may appear to only be relevant when talking about a building’s exterior. However, an exterior trim contributes to keeping the home safe from outside elements, and it should be properly installed in any construction project. Here at Fine Remodeling, we are your Delaware contractor experienced with performance guidelines to ensure your renovation project proceeds smoothly. Not only that, but we are determined to go beyond just satisfactory so your project can become a reality. Get in touch with us about your next renovation project so you can be sure it's done right the first time.

Visit our contact us page and see our calendar to select a day/time for a discussion about your project.


Call 302-635-0375 to discuss your dream project.

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