Builder Interview Script
Quick Answer
These 12 questions help homeowners evaluate whether a contractor understands moisture management, material selection, and indoor air quality — the three pillars of the Good Air Standard. You do not need a specialized contractor. You need a competent one who is willing to follow a specification. These questions identify which contractors understand the principles, which are willing to learn, and which are not a fit.
How to Use This Script
Ask these questions during your initial conversation with any contractor you are considering for a new build or major remodel. The questions are designed to be non-confrontational — you are learning about their approach, not testing them. Most good contractors will appreciate a homeowner who knows what they want and has a clear specification.
For each question, we provide what you are listening for and red flags. A contractor does not need to know every answer perfectly. What matters is their willingness to engage with the concepts and follow a specification that may differ from their usual approach.
The $79 Build Package includes an expanded version of this script with option-specific follow-up questions for each of the 7 build options, plus a contractor spec pack you can hand to a builder for bidding.
The 12 Core Questions
1. "What do you use for exterior wall sheathing?"
What you're listening for: Awareness that sheathing choice matters beyond structural performance. Ideal: mentions plywood, fiberglass-faced gypsum sheathing, or MgO board. Good: mentions the option and is open to alternatives. Acceptable: uses OSB by default but is willing to substitute per spec.
Red flag: "We always use OSB — it's what everyone uses" with no willingness to discuss alternatives.
2. "Do you install a rainscreen gap behind the cladding?"
What you're listening for: Understanding of what a rainscreen does (drainage, ventilation, capillary break). Ideal: has installed rainscreens before and understands the value. Good: has not but understands the concept and is willing to learn. Acceptable: unfamiliar but asks questions and wants to understand.
Red flag: "That's unnecessary — we just put the siding right over the housewrap." This is a contractor who builds the conventional way and may resist specification changes.
3. "What type of insulation do you typically install in wall cavities?"
What you're listening for: Experience with mineral wool (stone wool) batts. Ideal: has installed mineral wool and can speak to the installation differences from fiberglass. Good: has not installed it but is open to it. Acceptable: primarily uses fiberglass but will follow a mineral wool spec. If the builder counters with sheep wool or another natural-fiber batt, Mineral Wool vs Sheep Wool gives you the reasoning to hold the spec.
Red flag: "Spray foam is the best insulation — we put it in everything." This contractor's default approach conflicts with the Good Air Standard's core principles. Not necessarily a bad contractor, but not aligned with your project goals.
4. "Do you install a vapor barrier on the interior of exterior walls?"
What you're listening for: Understanding that interior polyethylene vapor barriers can trap moisture and that vapor control strategy depends on climate. Ideal: knows when interior poly is appropriate (cold climates only, if at all) and when it is harmful. Good: is open to discussing vapor control strategy per spec.
Red flag: "Of course — poly on every wall, that's code." In many climates, this is not code, and even where it is, alternatives exist. A contractor who believes interior poly is universally required may not understand moisture dynamics.
5. "What type of drywall do you use?"
What you're listening for: Awareness that paperless (fiberglass-faced) drywall exists. Ideal: has installed it and knows it finishes the same way. Good: has not but recognizes the mold-resistance advantage. Acceptable: unfamiliar but willing to spec it.
Red flag: Strong resistance to anything other than standard paper-faced drywall with no willingness to discuss alternatives.
6. "How do you handle framing lumber that gets rained on during construction?"
What you're listening for: A moisture management plan for the construction phase. Ideal: checks moisture content before enclosing, allows drying time, has a protocol for mold on framing. Good: acknowledges that wet framing is a concern and is willing to follow a protocol. Acceptable: has not thought about it explicitly but is receptive.
Red flag: "It'll dry out once we close it up" or "A little rain never hurt anything." This is the conventional attitude that leads to mold behind drywall.
7. "If you find mold on framing during construction, what do you do?"
What you're listening for: A process beyond "spray it with bleach." The Good Air Standard protocol is: dry the lumber, HEPA vacuum the surface, seal with dewaxed shellac, cure and ventilate before enclosing. Ideal: has a similar protocol. Good: is willing to follow a specified protocol. Acceptable: has not encountered this but is willing to learn.
Red flag: "Hit it with bleach" or "Just spray a biocide on it and close it up." Bleach does not kill mold on wood (it kills surface mold but does not penetrate porous materials). Biocide sprays mask the problem without addressing the moisture source. See Mold During Construction Protocol.
8. "Are you willing to follow a written material specification for this project?"
What you're listening for: Willingness to work from a spec rather than their default material choices. Ideal: "Absolutely — give me the spec and I'll bid it." Good: "Sure, as long as the materials are available and the budget works." Acceptable: asks questions about what the spec includes.
Red flag: "I use what I know works — I don't need a spec." This contractor is telling you they will not follow your material selections. For an IAQ-focused build, the spec is the project.
9. "What adhesives and sealants do you use at windows and penetrations?"
What you're listening for: Awareness that adhesive and sealant selections affect indoor air quality. Ideal: knows the products by name and can discuss VOC content. Good: uses "whatever the supply house carries" but is willing to switch to specified products. Acceptable: has not thought about it but is open to the conversation.
Red flag: Indifference. Adhesives and sealants are the most commonly overlooked VOC source in otherwise well-specified homes.
10. "Have you built a home with an ERV or HRV system?"
What you're listening for: Experience with balanced mechanical ventilation. Ideal: has installed ERV/HRV systems and understands ductwork requirements. Good: has not installed one but is familiar with the concept and willing to coordinate with an HVAC contractor. Acceptable: unfamiliar but asks good questions.
Red flag: "Just open the windows — you don't need all that." Mechanical ventilation is a core requirement of the Good Air Standard. A contractor who dismisses it may not align with your project goals.
11. "Can you walk me through how you detail a window installation?"
What you're listening for: A methodical approach to flashing — sill pan, jamb flashing, head flashing, integration with the WRB. Ideal: describes a specific sequence with specific products. Good: describes a general approach consistent with manufacturer installation instructions. Acceptable: refers to manufacturer details and follows them.
Red flag: Vagueness or "we just caulk around them." Window flashing failures are the number one source of concealed moisture damage in residential walls. A contractor who is vague about window details is a risk.
12. "How do you feel about a homeowner who has specific requirements for indoor air quality?"
What you're listening for: Respect for the homeowner's priorities. Ideal: "I appreciate when a client knows what they want — it makes my job easier." Good: "I haven't done this before but I'm interested." Acceptable: honest questions about what it involves.
Red flag: Dismissiveness, eye-rolling, or "You're overthinking this." A contractor who dismisses your concerns during the sales conversation will not prioritize them during construction. The best contractors are curious, not defensive.
How to Evaluate the Responses
You are not looking for a contractor who already does everything on this list. You are looking for a contractor who demonstrates three qualities: competence (they understand building science fundamentals), willingness (they will follow a specification that differs from their defaults), and curiosity (they engage with the concepts rather than dismissing them).
A contractor who scores "ideal" on every question is rare and may not be necessary. A contractor who scores "good" or "acceptable" on most questions and shows genuine willingness to learn and follow a spec is a strong candidate. A contractor who hits two or more red flags is not the right fit for this project — they may be an excellent general contractor, but their approach conflicts with the priorities of an IAQ-focused build.
For help finding contractors who are open to these approaches, see Find a Builder. For the expanded interview script with option-specific questions and a contractor spec pack, see the $79 Build Package.
Last reviewed: August 2026