The vast majority of siding proposals are presented as a single number for a specific product. Thus it is almost impossible to compare bids for the same house. In reality two bids for the same house can be as much as thirty percent apart and this is not necessarily due to the difference in products. Rather it could be due to whether or not the bid includes the cost of tear-off, whether or not it includes the cost of repairs to the sheathing, and whether or not it includes the cost of replacement of the flashing. It could also be due to the bidder’s assumption as to the condition of the walls of the old house.
Reading a proposal as a scope document, not a price
The contractor explains in great detail what is happening behind the siding as it is installed. This goes far beyond a simple list of products that can be found on a contractor’s website or in a brochure at a siding retailer’s showroom. By reading through a contractor’s scope of work, you can uncover a host of shortcuts that a contractor may have taken in an attempt to save money, only to have those very same shortcomings reveal themselves as the contractor opens up the wall to install the new siding.
Line items that should appear on every bid
- Full tear-off versus installation over existing cladding, with the reasoning stated
- Water resistive barrier type, lap direction, and whether it is being replaced or retained
- Flashing at windows, doors, decks, roof-to-wall intersections, and penetrations
- A stated unit price for sheathing and framing repair, with an allowance for square footage
- Trim, soffit, fascia, and corner treatment, since these often get excluded quietly
- Debris removal, site protection, and final inspection procedure
Now that we have the scope for each bid defined by the same six items, we can start to look at the numbers and get a sense of the differences in how each contractor is approaching the job and in how they are pricing their work. Thus, for example, a very low bid for siding may actually turn out to be more expensive in the long run if flashing replacement was not included in the bid.
Matching material to exposure and wall assembly
Most exterior siding products can be installed on a variety of exterior wall types. Each exterior siding product has its own set of benefits. When selecting an exterior siding product for a house, it is wise to consider the exterior wall type of the house. For example, houses with continuous exterior insulation require siding fasteners that reach through the foam insulation and attach to the structural framing of the house. In some cases, exterior drying to the exterior of the house is very limited. In these cases, exterior siding products that incorporate a rainscreen into the installation of the exterior siding are recommended.
| Material | Installation demands | Typical upkeep interval | Common failure mode |
| Vinyl | Loose nailing for movement, precise starter and J-channel work | Washing every 1 to 2 years | Buckling from overdriven fasteners, wind release at locks |
| Fiber cement | Cut-edge sealing, clearance to grade and roofing, blind nailing | Repaint at 10 to 15 years | Edge swelling and paint failure at unsealed cuts |
| Engineered wood | Strict end-joint flashing, tight moisture control at bottom course | Repaint at 8 to 12 years | Moisture wicking at unprotected ends |
| Cedar | Back priming, stainless fasteners, ventilated furring | Stain or seal every 4 to 6 years | Cupping, tannin bleed, fastener staining |
Testing installation competence rather than credentials
First, a siding contractor must have a contractor’s license to perform work on a homeowner’s property. In addition, the contractor must have proper insurance to protect the homeowner in case of an accident on the job. After that, the real question is whether or not the contractor follows the manufacturer’s published installation instructions for the siding that they are proposing for use on the homeowner’s property. The warranty provided by the manufacturer of the siding is only good as long as the siding was installed according to the manufacturer’s published installation instructions. Therefore, the contractor’s workmanship warranty is the most important aspect of any proposal for siding.
Questions that expose method
- What clearance will you hold between the bottom course and grade, hardscape, and roofing?
- How will window head flashing tie into the water resistive barrier?
- What fastener type and spacing does the manufacturer specify for this wind zone?
- How are butt joints handled, and will joint flashing be visible or concealed?
- Who inspects the wall after tear-off and before new cladding goes up?
For siding installation, homeowners are usually best served by working with experienced Annapolis siding contractors, who will tell you what dimensions they will work within, what documentation will be used to complete the installation (i.e. Manufacturer’s instructions), and what fasteners will be used in the completion of the siding installation as well as the methods of water drainage that will be utilized in completing the siding installation.
Separating workmanship coverage from product coverage
Most siding manufacturers will give you a 10 year prorated warranty on the siding itself. The workmanship warranty on the other hand can be worth so much more. Most siding failures are caused by improper installation of the siding and the surrounding trim. So the workmanship warranty typically lasts 5 to 10 years.
What to confirm in writing
Ask for the term of the workmanship warranty and what it will cover. Find out if the workmanship warranty will be transferred if the home is sold. Typically there are exclusions for pressure washing with high PSI, third party penetrations (i.e. Satellite dishes), and unapproved paint systems. A 5 year workmanship warranty from a good company with good service is far better than a “lifetime” warranty from a bad company with no service history.
Planning maintenance before the crew leaves
Sealant joints around exterior trim items and penetrations through the building, such as for electrical, plumbing and HVAC units, generally need to be re-sealed every 5-7 years. If not re-sealed, the sealant will fail allowing water to enter and cause damage to the exterior finish of the building. In addition, gutters and downspouts that discharge against the building wall can also cause damage to the exterior finish of a building before the normal weathering process occurs.
Ask for a closeout package with manufacturer documentation, the batch number or color code of the siding, any leftover materials for future repairs, and photographs of the completed wall assembly prior to completion of exterior cladding. These photographs will act as proof of all components of the exterior wall and aid in any future repairs, appraisals or insurance claims.
