How To Look At A House
McGarry and Madsen's home inspection blog for buyers of
site-built, mobile/manufactured and modular homes
How can I tell if vinyl siding is installed correctly?
Wednesday, September 19, 2018
Vinyl is a popular siding choice for home builders and mobile home manufacturers because the material is cheaper and easier to install than other alternatives. The bonus for homeowners is that vinyl is also low maintenance. But, like most other siding materials, vinyl is water-resistant but not waterproof. It requires a house wrap (vapor barrier) covering the wall sheathing below the siding for adequate weather protection. Correct installation of the house wrap is very important, especially at the door and window openings.
The vinyl panels are installed in a way that allows them to expand and contract with changes in temperature. A nailing hem at the top of the panel has slots for the fasteners and the panel will slide easily along its length if the nails are not driven too tight to the siding. A gap about the thickness of a dime is recommended. The hem is covered by the strip of siding above it which interlocks with the flange at the top of the hem.
Because the nailing area is not visible on the completed home we look for symptoms of improper installation such as sagging or buckling. Often repairs to siding using exposed fasteners (called face nailing) will be present. This is not considered waterproof and interferes with the thermal expansion and contraction of the material. In the photo, below you can see where the panel buckles in both directions because it is trapped by the screw.
You also want to keep your outdoor grill a good distance from the wall. An oval area of melted and sagging siding on the wall facing a back deck of a home is a sure sign of a barbecue boo-boo.
Vinyl siding terminates into J-channels at window and door openings, corner boards, light fixtures, hose faucets, dryer vents and electrical disconnect boxes. Special individual mountings for these items are available and include mounting blocks. These strips not only help to waterproof the connections, but give the ends of the panels room to expand.
Vinyl siding is also subject to impact damage, especially when string weed-trimmer is used a little to close to the siding.
Most vinyl siding is fashioned to look like ship-lapped wood siding, however the products are also available in wood shingle, beaded board, and board and batten styles.
Also, see our blog posts What is the average life expectancy of vinyl siding? and Can vinyl siding be painted?
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To learn more about exterior walls and structures, see these other blog posts:
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