Let’s Talk About Vinyl Siding, Part 1

While a variety of materials are used as exterior wall coverings for manufactured housing, vinyl siding might be the most common. So, let’s look at some of the issues that are often overlooked regarding vinyl siding installation.

Everybody knows that vinyl siding expands and contracts with changing weather conditions, Experts say a single 12’ long piece of siding can be expected to grow or shrink up to 5/8” in length. You must allow for this movement as you install the siding on the home. Here are some key points to consider:

Siding box instructions, leave 1/32″ under nail head or staple crown to allow the siding to expand/contract.

Vinyl siding should be “hung” on the side/end walls of the home. When installing nails or staples, be sure to leave at least 1/32” (thickness of a dime) between the nail flange and the nail head or staple crown.

For horizontal panels and accessories, start installing fasteners in the center of the panel and work towards the ends. Install the nails/stapes in the middle on the nail slot. Don’t angle the fastener or use it to pull on the panel.

For vertical applications (including corner posts and “J” channels) along the sides of windows and doors, apply the first nail or staple at the top of the top most nail slot (to keep it from slipping down) and the remainder of fasteners in the center of the nail slot.

Fastener spacing is generally 16” apart for siding panels, and 12” apart for channels and accessories. If the slots and framing studs don’t align to allow you to center the fastener, use a slot punch tool to enlarge the slot,

When installing a new manufactured home, the manufacturer will be providing you with the proper nails or staples to install the siding. But, for a relocated manufactured home it will be up to you to determine that you have the right fastener for the job. In all cases, the fasteners must be corrosive resistant, such as aluminum nails, galvanized roofing nails, or galvanized staples.

Look closely, these staples are galvanized to resist corrosion.

Also, be sure the fasteners are the proper length, about 1 ¼” of penetration into the framing of the home. If the home is sheathed with OSB (oriented strand board) or some other nail-able sheathing, you can generally install some fasteners in the sheathing, but be sure to make an effort to hit every framing studs. If you are installing siding over a foam insulation, you will need longer fasteners in order to achieve the 1 ¼” penetration needed.

The thing that I believe is most overlooked in regards to vinyl siding installation is the need for utility trim. Also called finish trim or under-sill trim, it’s needed to secure the siding wherever the nailing flange has been removed, most notably under windows or doors. The utility trim should be cut about ¼” shorter than the section of nail flange that has been removed, and fastened directly to the wall, under the window, door, etc. Using a snap lock punch, punch lugs every 6” along the cut edge. When installing the panel, slip the cut edge into the utility trim to secure it in place. If your manufacturer is not providing or using utility trim, start requesting it!

Siding panels should be cut and installed allowing for about ¼” gap between the panel and the inside of the receiving “J” channel, corner post, backer block, etc.

 

Siding panels should overlap each other by 1” to 1 ½”. If you have to cut off the factory pre-cut edge, be sure to notch both the nail flange and the bottom lock to allow for lateral movement of the siding.

If the factory end is cut off, be sure to re-notch the bottom of the siding panel as well as the top!

Be sure to stagger the joints by about 12” unless separated by three courses. Don’t use short pieces that cannot be fastened to two studs. This is particularly true along the gable end, under the overhang on the end walls. The very last piece of siding at the gable can be fastened with an aluminum trim nail. Drill an 1/8” hole and don’t drive the nail tight. Snug will do it! This should be the only exposed fastener needed for siding application.

Be sure to leave enough nail flange to allow attachment at 2 studs!

Ok, that is enough for now. As always, be sure to follow the actual siding installation manual and product instructions! We will discuss this topic further in our next post!

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