Miters Yes, Edge Sealing No: Frequently Asked Questions About TruExterior Siding & Trim


TruExterior’s proprietary blend of polymers and fly ash brings about a number of benefits—including some that go against installers’ long-held knowledge about what siding can do and how it needs to be installed. For example, did you know you don’t need to seal end cuts in the field? Did you know you can paint TruExterior black without any special treatments?

Because the siding is the first of its kind in the market, we devote a lot of time to helping installers learn about the material and, in some cases, un-learn old installation requirements. Here are a few of the most common questions about TruExterior. If you have more, don’t hesitate to reach out! Find your local dealer here.

Q: Do I need to use a special blade to cut TruExterior?
A: TruExterior cuts and installs using standard tools. We do recommend carbide-tipped blades and bits, as they last longer. TruExterior may dull the blade for cutting other materials that require a sharper edge, so some customers have found it easiest to simply have a blade dedicated to TruExterior.

Q: What type of fasteners can be used with TruExterior?
A: TruExterior products can be installed using standard nail guns or screws, and standard trim nails work well. Like with any siding installation, use high-quality, exterior-grade fasteners suitable for the conditions of the application.

Q: When installing, do I need to leave space for expansion and contraction?
A: TruExterior products are extremely stable during periods of temperature and moisture change*, so no special measures are necessary to limit or control movement. (*Please see Boral TruExterior Trim and Boral TruExterior Siding Limited Warranties and Product Data Sheets for proprietary test results.)

Q: Can TruExterior Trim be mitered?
A: Yes! TruExterior Trim takes a miter cut easily, and, unlike many other trim products, fasteners can be nailed or screwed through the miter joint.

Q: Some siding products require a drip edge and flashing; do I need to do that with TruExterior?
A: Because TruExterior Siding & Trim has such a minimal moisture absorption rate, there is no need for drip edge or flashing.  That said, in some cases it may be a requirement for the warranty of the adjoining or adjacent product or may even be a best practice for water management in high moisture areas. TruExterior can even be placed below grade and have direct masonry contact!

Q: Do I need to prime TruExterior?
A: TruExterior products come with a factory-applied primer. Because TruExterior products absorb virtually no moisture, ends and field cuts do not need to be primed or sealed.

Q: Are there any special instructions prior to painting?
A: Make sure the boards are dry prior to painting and that surfaces are free from dirt and debris. Because TruExterior has a high level of dimensional stability, there is no need for special paints when using a darker color. Use any high-grade exterior paint of any color. Be sure to follow your paint manufacturer’s guidelines.

Q: Do I need to use adhesives when installing TruExterior?
A: No. However, exterior-grade acrylic caulk and adhesive may be used to smooth out joints or miters prior to painting.

Haven’t tried TruExterior Siding & Trim? Request a sample.