Hello All:
We will be breaking ground in 2 months (May 2026) for our 1,500 sq feet, 2 story home in western NY State. However we have a problem with the radon mitigation system to be set up under the basement floor piece.
We mean to put in a 5-inch layer of washed stone (grains approx 1/2 ″ to 3/4 ″) with 4-inch perforated pipe to gather radon and exhaust out through a vent pipeline in the roof. We plan to use passive venting given that we live near the top of a hill and have lots of wind for Bernoulli result.
However we have a concern with the under-slab wastewater drainpipe, which will extend throughout the whole width of the foundation (see images). The sewage-disposal tank is off to the ideal side of the structure, and we need a floor drain all the way over on the left side. The drain blocks the path of a radon collection pipe for most of its length, thus cutting off the upper part of the structure.
It appears there are 2 possible arrangements:
Option 1: (Image 1) Confine the radon collection pipe to the region listed below (in the image) the wastewater drainpipe, trusting the permeability of the stone to permit radon to flow from the upper area to the collection pipeline.
Option 2: (Image 2) Cross the radon collection pipe over the wastewater drainpipe at its floor, just before it exits the structure. Due to the slope of the wastewater pipeline, there should be enough space here in between the underside of the piece and the top of the wastewater pipeline for the radon pipeline to fit through. Then the radon pipeline can be extended into the area in the upper part of the structure.
We are wondering if it deserves the additional effort to extend the radon pipe all the way into the upper part of the structure, specifically because it will be a long method around the pipe circuit for the gas to take a trip to the vent? Or would it be effective to just put collection pipe in the lower part of the foundation only, and trust the gas streaming through the permeable layer of stone to get to the collection pipe?
Any ideas on this question are much valued.