Questions to ask a contractor

10 Questions To Ask Potential Contractors When Building Your Healthy Home

We are wrapping up our series on 'How to Begin a Wellness Home Build' with some guidance on choosing the right contractor for your project.  Choosing a contractor can be a tricky task!  Not all contractors are created equal.  Some contractors are much more experienced in building durable, energy efficient, healthy homes than others.


The best way to find a contractor that will build your healthy home correctly is to ask lots of questions!  It is a good idea to interview up to three contractors before hiring the team that will build your home.  

You want to make sure they are going to build a quality healthy home and that they are willing to learn some new tricks along the way.  Here are 10 great questions to ask your potential contractors to make sure they are comfortable building your healthy home.  

Watch the video!  10 Questions to ask a contractor...

Video Summary:

1.)  Are you willing to be a part of an integrated design team, meeting with the whole team from the early stages of the design process through construction?

This is a good question to start with because you need to have a contractor that is willing to put in more time upfront to have a smooth construction process and build a truly healthy house.  If they are invested in making a healthy home, they will see the value in working with you and the design team from the very beginning.  This may take more time for them upfront, but it will save them time and frustration during construction.  

Find out about the importance of an Integrated Design Team here.

2.)  Do you build air tight homes?  What are your air tightness test results (from blower door tests)?  

This is another great question to start out with because you'll get an understanding right away on whether or not this builder believes homes should be air tight.  If you have a builder that tells you the house needs to breathe, then they do not understand how to keep your house healthy and energy efficient.

3.)  What do you use for a water/weather resistive barrier?

A weather resistive barrier helps keep water out of your wall cavities, reducing the likelihood of mold growth.  If a builder says they use perforated house wrap, they are putting the worst kind of weather barrier on your house.  They are doing this because it is cheap and, ultimately, water will get into your wall cavity.  

Tyvek house wrap is good, but Zip System, peal and stick or fluid applied is better.

4.)  Do you use a rain screen system for siding? 

A rain screen is another step against keeping water and moisture out of your walls.  A rain screen system is basically a ventilated gap between the  exterior sheathing and the siding.  This gap allows any water that gets behind the siding to run down the outside of the wall rather than get trapped against the wall and eventually soak into the wall.  A rain screen takes more time to install which can turn some contractors off, but material costs are not much higher.  

If the contractor is unfamiliar with the term 'rain screen' that's ok, as long as they understand and put into practice the concept of providing a ventilated air gap between the siding and the sheathing.

5.)  What are your insulation methods?   Exterior continuous insulation? Interior spray foam?   

Hearing out a contractor's thoughts on insulation is helpful to get an indication on their understanding of health and building science.  

Continuous insulation on the outside of your home is the best way to insulate the house, but it is costly in labor and materials.  Don't rule out a builder that doesn't do this regularly because it is often nixed by the homeowner, not the contractor's unwillingness to do it.  

When it comes to exterior rigid continuous insulation, the contractor needs to understand how thick the exterior rigid insulation is, and how much cavity insulation to put in the walls.  Having this understanding means they understand where condensation will occur within the wall.  If they know to put on enough exterior insulation to make sure condensation happens outside of the wall cavity, then they are familiar with building science principles, which is a good thing.

If the contractor loves and insists upon spray foam, they do not understand the harmful impact it has on human health and the environment.  Spray foam is a great air barrier, but that's about it.  Its other problems outweigh the air sealing benefit.  I would be leery of a builder that doesn't want to use alternative methods of insulating.  

6.)  Do you air seal the mechanical room to keep it air tight from the rest of the house (if combustion appliances are used- furnace, water heater)? 

This is now a code requirement, but many jurisdictions have not adopted recent codes.  Any time combustion happens inside your home, CO is potentially created.  If the appliance is in its own room that is completely sealed from the rest of the house, the CO and other harmful byproducts likes nitrogen dioxide, will not travel into your home.  They will be exhausted properly to the exterior.  

This will demonstrate the contractor's understanding of the dangers of combustion products and the importance to having the products in their own air sealed room. 

7.)  Do you use whole house mechanical ventilation systems?  If so, are they balanced systems?

An air tight house must be mechanically ventilated and a builder needs to understand that.  The best way to do that is with a balanced whole house ventilation system.  Sometimes builders will install an exhaust only system, which relies on the supply air coming from leaks in your building envelope.  You don't want this.  

A balanced system can be achieved by installing both a supply fan and an exhaust fan or by installing an HRV/ ERV.  

8.)  Are you able to source building materials that are not typical materials?

Builders have go-to materials and suppliers (for good reason! - it is efficient and saves the owner time and money), but some healthy home products might not be on their go-to list which means that have to do some work to find a supplier.  This takes time on their end.

Side note: There are many go-to products that are healthy products.  We are not trying to make the contractor source crazy, unheard of products.  But if the builder's standard products are harmful when healthy options are readily available, we expect that they will source the healthier option.

9.)  Would you be willing to learn to install new materials? 

If builders are using unfamiliar building materials, they are going to have to learn how to install them correctly.  This means more time on their end to learn something new.  

We do not want your house to be a test home, so we do not want to introduce a bunch of materials that are totally foreign to all builders.  But there might be a few that the builder hasn't used before, such as a fluid applied window flashing.  

10.)  Are you willing to oversee and inspect your subcontractors' work to make sure things are being installed per drawings and inspections? 

Every contractor should be inspecting their subcontractors' work, but when things get busy this doesn't always happen.  When building a healthy home, it is very important that things are installed a certain way and with certain products.  A contractor needs to monitor this to make sure the right practices and products are being used.

Example: Countertop install. Typical installation is by gluing with toxic adhesives.  A healthy home will specify a countertop that can be mechanically fastened.  The builder has to ensure that this is how the countertop will be installed.

Final Thoughts...

Choosing the right contractor will make your life easier and your project go smoothly.  It will also ensure that you are getting a healthy home.  Asking the right questions before signing on with the contractor will help to make sure you are choosing one that truly understands and appreciates building a healthy home.

Don't forget to download the FREE cheat sheet so you have the questions readily available for your contractor meeting.