Threshold
About Threshold

Threshold

There is a kind of knowledge that has, until now, never had a home.

It lives in the notebooks of building biologists. In the closed forums of mold and carbon monoxide survivors. In the case files of functional medicine clinicians. In the lecture halls of building science conferences. In the lived experiences of people who got sicker in one home and better in the next, and quietly began to suspect why.

The connections are real. The mechanisms are increasingly well-understood. But the knowledge itself is scattered across so many disciplines that no single practitioner can reasonably hold it. The architect does not read the toxicology literature. The toxicologist does not spec the HVAC. The mechanical engineer does not stay current on immune system research. The integrative physician does not write the materials palette. And the household with a cancer diagnosis, or heart disease, or a child with sensory processing differences, is left to translate across three or four professional vocabularies that do not share a common reference.

Threshold is that reference.

A structured, citation-grounded, evidence-tiered map of how the built environment meets the specific human living inside it. Not a wellness blog. Not a building code. A working reference for the practitioners doing the actual work, organized around the question they actually need answered: this client, this condition, this home, what changes?

Courtney Lebedzinski, founder of Wholesome Houses and creator of Threshold.
Courtney Lebedzinski, founder of Wholesome Houses

How I Came To This Work

I am Courtney Lebedzinski. I am a Building Biology New-Build Consultant candidate, completing certification through the Institute for Bau-Biologie and Ecology, and the founder of Wholesome Houses. My background is in real estate.

I came to building biology the way most practitioners in this field do. Through my own body.

I became a mother in 2011 and for the next eight years we moved nearly every year, sometimes twice: the life of a military spouse. Eight homes in eight years. Different cities, different climates, different construction eras, different materials, different mechanical systems, different ground beneath us.

The first home was the one that made me the sickest.

I had debilitating IBS-like symptoms there. I had terrifying hypnagogic hallucinations. I did not yet have the framework to ask why, and the home was never tested. Looking back with what I now know, I suspect a stacked exposure profile: the head of our bed backed against the wall where the washer and dryer ran, often through the night; a cell tower stood less than a mile out, in line of sight from the bedroom; the home was old enough, in a climate humid enough, that hidden mold is a reasonable suspicion. I will never know for certain. The point is not the diagnosis. The point is that my body was warning me in a language I didn't yet understand.

The pattern revealed itself the way most quiet truths do. Not in a moment of insight, but in a moment of contrast.

We left that home and spent a few months in a temporary apartment, then moved cross country, from Alabama to Illinois. In the new place, unpacking, I came across an unopened colonoscopy prep kit I had ordered in the previous home, out of desperation for answers, and had forgotten in the rush of the move. I stood there holding it and realized I had not had a single stomach symptom in weeks.

I had walked out of the house, and left the symptoms there with it.

Once you have noticed that, you cannot unnotice it. Each subsequent move sharpened the data. Some homes I got worse in, some I got better in. The pattern was not subtle, it was not seasonal, it was not stress, and it was not in my head. The variable was the building.

Midway through those years, I started formal training in Building Biology, and the language caught up to what I had been observing. I read the toxicology. I built relationships with the most rigorous practitioners in the field. And along the way, I noticed the same gap, over and over. There was no central place where a designer working with a specific client and a specific condition could go to ask the obvious question: what does this body actually need from this home?

There was no reference. So I built one.

What Threshold Is, And What It Is Not

Threshold is the reference I wished existed when I was the body in the building, written now for the practitioners who need it most.

It is not a substitute for clinical care. It is not a marketing tool. It does not rank countertops or sell air purifiers. It is something more disciplined, and I think more important: a structured map of the specific places where the built environment meets occupant health, with the evidence cited honestly and the design implications spelled out at a level of detail a practitioner can actually use.

The reference is opinionated. It is willing to disagree with the field where the field has been wrong, or vague, or untested against the specific human in front of you. It engages substantively with WELL, with LEED, with Building Biology consensus, with functional medicine, crediting what each does well and naming where each breaks down for occupants whose biology does not match the default assumption. It tiers evidence transparently. It says when it is sure, and it says when it is reasoning.

For exactly how Threshold organizes evidence, classifies conditions, and curates each connection between body and building, see the Methodology.

Why This, Why Now

For the same reason the field of functional medicine emerged a generation ago: the conditions are real, the prevalence is climbing, and the existing system is not designed to meet them.

The household with the kid who reacts to mold. The mother with lupus. The father worried about dementia risk. The client with multiple sclerosis who needs to age in place in a home that does not actively work against her body. These households are not edge cases. They are the work. And the work deserves a reference.

This is mine.

Courtney Lebedzinski