This post is for those building or refinishing stairs who want to build with as few toxins as possible. The chemically sensitive will want to consider the pressed wood products, glues, and finishes that are normally used.
For all the aspects that need to be considered at the start of a build for the chemically sensitive see my post on this topic.
Can you Build Stairs without any Glues or Toxins? (Solid Wood Stairs)
Stairs can be made out of all solid wood without any OSB or plywood. When building stairs out of solid wood, there would not be another finished flooring over it, the structure of the stairs would be the final product.
With solid wood stairs usually some wood glue and some construction adhesive will be needed.
Though old school methods could be used that do not require glues. You would look for an old-school or skilled carpenter here and discuss that at the very start of the project.
Construction adhesive is normally used under the treads to prevent squeaking. It wasn’t used in the past, though of course stairs were squeaky.
In older buildings, I have seen stairs that are creaky or have visible nail heads. To go to the most extreme with avoiding chemicals, you would discuss all the small details upfront- like do you want to use a filler to cover up the nail heads or do you want those to be visible.
You can use solid wood for all components of the staircase if you plan this into the design.
For non-toxic wood finishes see my post on sealers.
Conventional Stairs – Toxins and Glues Used
Convention stairs are usually a mix of real solid wood and OSB or plywood. OSB and plywood, of course, contain adhesives – phenol-formaldehyde and or MDI.
It’s not unusual to see MDF used for the risers, that’s one you certainly would want to avoid.
You may also see veneer glued on the riser.
Specify exactly which types of engineered wood are acceptable and which construction adhesive. See my post on engineered woods to see which adhesives are used in each type, and what they offgas.
In large houses, there may also be engineered beams used as the support system for the staircase. If you are avoiding engineered lumber, plan this into the design in the beginning.
In this case, where the stairs are not made of solid wood, your final flooring goes overtop of this structure.
Subfloor glue/construction adhesive would be used here.
Non-Toxic Finishing Materials for Stairs
A number of finishing materials can be used on the stairs, whether they are new stairs or old ones where carpet or another material was removed.
LVP (vinyl) would be glued down. I don’t find most of the standard glues to be very tolerable or healthy. See my post on flooring for more about LVP.
Laminate systems also involve a fair amount of glue.
Engineered wood is usually glued down. A carpenter I spoke with said this could be done without glue, but it would be trickier. Engineered wood is not a bad option for those looking for a green and healthy option but solid wood is still preferred.
I do think there are good options for non-toxic carpet available for the chemically sensitive like HomeFresh, I list them in my post on flooring. First carpet pad goes down with staples. The carpet can also go down just with staples or tacks which is a benefit here, as this skips glue
Non-Wood Options for Stairs
Staircases can be made of just metal or concrete, concrete with tile or stone.
I would not use MgO board as the structure of any part of a wooden staircase.
This post was written with the assistance of Brad Campbell, Carpenter and Engineer.