first story of a slab on grade

[Mark300]

2-story SOG house in climate zone 4 (BC Canada).
The downstairs is finished (R-13 fibreglass batt insulation in walls and drywall) and laminate flooring. Foundation is exposed ~10” above grade. I believe no insulation under slab or perimeter (80’s build). New double pane windows.
No moisture/water intrusion from slab. No significant cracks. Drainage around the house is good.

I had to post this because I’ve spent months trying to fix the issue using material online with no success.

Anytime I or my family stay downstairs, we get a weird feeling in the chest/abdomen. It’s a feeling that makes you want to cross your arms to alleviate the pain. Staying upstairs there is no such reaction at all. Otherwise healthy individuals.

Having reviewed a lot of the posts on the forums, I’ve checked:
1) No CO detected.
2) No radon.
3) Gas fireplace downstairs. A thermometer reads 72 F while the fireplace is on low. Ceiling fan is on to circulate the air.
Also, the forced air system (shared for both floors) has one return vent and several supply vents (all on the ceilings) spread throughout the living space.
4) I installed 1” EPS subfloor (Dri-core) and laminate so the floor is now OK at retaining heat.
5) Humidity measures the same upstairs and downstairs, 47%.

I read that most of the heat loss in a slab on grade is on the perimeter. Is this what’s causing the comfort issues?

I used an IR gun to measure some areas in winter: 55F on the bottom of the wall downstairs, at eye height the wall measured 60F, the floor with the fireplace on measures 62F. The bottom of the wall upstairs measures 68 F.

 

[WorthFlorida]

Anytime I or my family stay downstairs, we get a weird feeling in the chest/abdomen. It’s a feeling that makes you want to cross your arms to alleviate the pain. Staying upstairs there is no such reaction at all. Otherwise healthy individuals.

This is strange. It could be an air pressure issue, not temperature. Does this happen in the non heat season? Are there windows that can be opened to alleviate air pressure changes?

You say you checked the CO level, do you have gas furnace or water heater? Is there a good air flow up the chimney? Outside prevailing wings can drastically impact inside air pressure due to all the leaks from doors and windows, dryer vent and plumbing vents. When a dryer is running, it pushes at least 100 cuft of air outside. Replacement air will come down from the chimney.