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Siggins Rustic 105 1

Jul 19, 2023

Everything You Need to Know About 105 Siding

Tags: Siding

If you are looking for a rustic siding option that is easy to install, durable, and visually stunning, Marks Lumber’s 105 siding may be the perfect option for you. 105 siding, also known as Drop Siding, Cove Lap, Dutch Lap and German Lap, was a popular siding choice during the late 1800s and early 1900s.

105 Siding Profile

105 siding is a shiplap siding with an aesthetic round reveal that provides a beautiful, durable, protective barrier for your home. Marks Lumber’s 105 siding boasts a beautiful circle-sawn texture with a smooth reveal. The variance in textures provides a unique look that helps break up the look of the boards. The round reveal makes 105 siding ideal for horizontal installation as it helps slick water off, but it can also be installed vertically.

Zero Maintenance Finish

When you’re going for zero maintenance with a natural finish, we recommend using Lifetime Wood Treatment. This one-and-done weathering treatment provides a protective barrier that enhances the natural beauty and grain of the wood. Applying Lifetime to Marks Lumber’s 105 siding creates a beautiful, weathered look that enhances the look of this classic siding profile.

Types and Uses

Marks Lumber’s 105 shiplap is made from Made-in Montana, Grown-in-Montana Douglas fir. Each plank is milled using our circle-sawn head rig, kiln-dried, and hand graded. Our circle sawn 105 siding uses eight-inch wide (6 ¾” coverage) planks and comes in either an appearance or rustic grade.

105 siding has both interior and exterior applications. On the outside of your home, use it for either vertical or horizontal siding. Inside, 105 is great for wall paneling, ceilings, and wainscoting.

105 Siding Installation

Proper installation of wood sidings is critical to their longevity. We recommend following Western Wood Products Association (WWPA) guidelines for installing and finishing our sidings. With correct installation and maintenance, wood sidings should last for many years. You can download our complete installation guide here.

Step 1: Acclimation

As with most wood products, acclimating siding is critical for quality installation. Stack siding materials with space between them for a minimum of 10 days for dried Marks Lumber products.

Step 2: Pre-finishing/Finishing

Finishing is one of the most important steps in the installation process. In dry climates, as we have in Montana, pre-finishing is advised. This means both sides, edges, and all cut ends should be pre-finished or primed. Make sure your pre-finish is compatible with the final finish products.

If you choose a water-based finish, keep in mind that it can add significant moisture to the boards, which can lead to swelling. Make sure you allow time for the siding to re-dry and acclimate after pre-finish and before installation.

Step 3: Installation

Natural wood siding should be installed over a weather-resistant barrier for all sheathing materials. If sheathing or the weather-resistant barrier gets wet prior to installation, allow the surface to dry before installing the siding. When siding is applied over wood-based sheathing, nail penetration should be 1 ½ inches for smooth-shank nails (not recommended) and 1 ¼ for ring-shank nails.

For vertical installation, siding should be nailed to horizontal blocking not exceeding 32 inches on center. To join pieces of siding, cut a bevel on the ends of both pieces of material you’re joining (scarf joint).

When installed over sheathing horizontally, siding should be nailed to vertical studs on maximum 24-inch centers. If nailed directly to studs, they need 16-inch centers or less.

Maintaining Wood Siding

Most finishes on natural wood sidings benefit from regular washings. A light-pressure power wash with a product like Perma-Chink Systems’ Log Wash will remove dust and harmful pollen.

Note: Wood never dies; it is going to swell, shrink and move with changes in temperature and humidity over its life. Good installation techniques have been developed to take this absolute fact into account.

Marks Lumber can help you understand what is feasible with your budget, so define what you want, let us know, and we’ll make it happen! Contact our sales team today for more information on our 105 siding.

*This post draws heavily from the Western Wood Products Association guidelines. Complete installation guides can be purchased at their site:

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