Failed siding doesn’t appear overnight. Most siding failures appear 2-3 winters after the siding is installed. It appears as buckled siding panels, unsightly staining between adjacent siding butt joints, or as undesirable moisture reads in installed siding sheathing. If a building owner discovers any of these defects in their siding, the only relevant question is who installed the siding and to what building code standards the siding was installed.
Screening a siding contractor for your home improvement needs to be a more in-depth process than just finding the lowest cost bidder. Reviewing the following key indicators of a quality contractor versus red herrings will assist you in your search.
Read experience as a record of specific assemblies
A company may have been in business for a long time, but that does not necessarily mean that they can complete a project using the correct method for installing siding over a rainscreen with fiber cement, or proper flashing of a wall with continuous exterior insulation. Ask for recent project examples and try to match the siding, wall assembly, and location of past projects to your own needs. Find out what wind zone a company has completed work in recently, as there can be significant variations in the required method of fastening siding.
While a company’s age may tell you that they have managed to survive for a long period of time, years in business will not tell you if the people sending their employees out to your site have any idea how to install fiber cement siding over a rainscreen or, for example, how to continuously flash a wall with exterior insulation. Ask for project history and look to see if they have completed similar projects using similar methods and products on similar buildings in similar conditions.
Questions that separate operators from resellers
- How is the water resistive barrier lapped at window heads, and who installs it, your crew or another trade?
- What is the fastening schedule for this product at this exposure, and where does that number come from?
- How do you handle penetrations for dryer vents, hose bibs, and electrical after the cladding is up?
- What happens when rot is found behind the old cladding, and how is that priced?
They are basically two different things, your siding manufacturer’s warranty covering defects in the product itself and the workmanship warranty offered by the siding installer covering the work done in installing the product. Both are important but can fail in very different ways.
Separate the two warranties and read the exclusions
A siding installation has two main promises. First, the manufacturer of the siding product will cover any defects in the product. Second, the installer of the siding will cover any defects in the labor for the installation.
Manufacturer warranties typically cover defects in the material for a set number of years and are usually prorated. Most warranties do not cover fading of finishes after a certain point. Many manufacturer warranties are also conditional on proper installation in accordance with published specifications. That means one fastening error can sometimes void the entire warranty for that product. Workmanship warranties vary greatly and are typically a good indicator of how much a contractor stands behind their own detailing and can vary from one year to ten years or more.
What to confirm in writing
- Whether the workmanship warranty transfers on sale of the property, and at what cost
- Whether the contractor is certified by the manufacturer for the specific product, which often extends coverage
- What the response window is for a warranty call, and who pays for access or scaffolding
Match the material to the wall, not to the brochure
The materials a contractor recommends for siding a building will end up dictating the labor costs, the cost of preparing the substrate, and the long term costs of maintenance. It’s thus important to note whether a contractor is simply selling materials, or if they are suggesting those materials based on past experience and actual problem-solving. If you are weighing options in the Triangle, a seasoned siding company in Durham NC should be able to explain why one product suits your wall assembly better than another before any brand name comes up.
| Material | Typical service life | Main installation risk | Ongoing maintenance |
| Vinyl | 20 to 40 years | Nailed too tight, restricting thermal movement | Washing only |
| Fiber cement | 30 to 50 years | Unsealed cut edges and inadequate clearance at grade | Repaint at 10 to 15 years |
| Engineered wood | 20 to 30 years | Field cuts left unprimed | Caulk and paint inspection |
| Metal | 40 or more years | Dissimilar metal contact and oil canning | Minimal, watch coating |
Judge installation standards by the details behind the panel
Siding is a drainage system, a barrier that needs to breathe, not a seal that leaks. Therefore, be very interested in a siding installer’s use of flashing and how he or she manages water. The finished surface is just that, finish. Pay little attention to it.
The details worth inspecting on a reference job
- Head flashing above every window and door, with end dams, not caulk alone
- Kickout flashing where a roof edge meets a wall, the most common source of hidden rot
- Correct clearance at roofing, decking, and grade, per the manufacturer’s published figures
- Furring or a drainage mat where the assembly calls for a vented cavity
- Joint treatment at butt seams, whether flashed, joint-taped, or covered with a moisture-shedding detail
Compare estimates on scope, not on the bottom line
Bids will vary from contractor to contractor based on how they perceive your scope. Make sure you understand what each contractor expects to be included and what they expect you to pay for. Require line-item estimates for complete exterior packages, as well as written change order procedures and rates before they start work on your project.
Require the bidder to complete a line-item-by-line-item breakdown of the work to include demolition, cost of any required substrate repair, cost of any required barrier, and cost of any required flashing. Specify the brands for barrier and flashing materials. Describe the trim in detail, and list the fastener types to be used. Require a written change order process that establishes an hourly rate or unit rate prior to the change order being approved.