Concrete block basement walls are hollow inside, and those hollow cores can carry soil gas from the ground up into the house. In some homes, suction under the slab is not enough on its own. We connect York homeowners with a local contractor who checks whether block wall suction belongs in your system.
How Block Walls Carry Radon
A hollow block wall is built from concrete blocks with open cells inside. Those cells connect from block to block, creating channels that run along and up the wall. Soil gas from outside the foundation can enter those channels through cracks, mortar joints, or the porous block itself.
Once inside the wall, radon can leak into the basement through holes in the block, gaps at the top of the wall, or openings around pipes and wires. The top course of block is sometimes left open, which gives soil gas a direct path into the space between the floor joists.
Because the wall is separate from the slab, suction under the floor may not fully reach the gas moving through the block cores. That is when wall suction comes into the conversation.
Sub-Slab Only or Adding Wall Suction
Most block wall homes still start with sub-slab suction. When the gravel layer under the floor is good and the block cores connect to it, suction under the slab often pulls from the walls too. The contractor can test that during the estimate.
If the walls are a major entry route, the contractor may add suction ports in the block wall itself and tie them into the same pipe and fan. This is a heavier design choice. It means sealing the open top course, major cracks, and other wall openings so the suction works inside the cores.
The written quote should explain why wall suction is or is not recommended for your basement, and what sealing comes with it. If the contractor suggests starting with sub-slab only and adding wall suction later if needed, that plan should be in writing too.
Working on Exposed Block Walls
On an unfinished block wall, wall suction is fairly direct. The contractor drills into the block cores at chosen points, seals a pipe connection to the wall, and runs that pipe to join the main system. Cracks, holes, and the top of the wall are sealed with suitable materials.
On a finished wall, the work is harder because the block is covered. The contractor may look for access in a utility area or plan around it. Ask how any opening will be closed back up.
Expect some dust from drilling block, controlled and cleaned up during the job. After the system is running, the gauge is checked and the starting level is marked. A retest confirms whether the combined design has brought the radon level down where it should be.
Find Out If Your Walls Need Suction
Hollow block walls do not always need their own suction, but when they do, the difference can be significant. With the right information, the next step is usually simpler than it first seems. Every home is a little different, and a short visit is the fastest way to learn what yours needs. Having the plan in writing makes the decision easier and the follow-up simpler. Call us and we will connect you with a local contractor who can test your York basement and explain, in writing, whether wall suction belongs in the plan.
Frequently Asked Questions
Is block wall radon suction installed in hollow block basements in York?
Yes, when testing shows it is needed. The contractor drills into the block cores, seals pipe connections to the wall, ties them into the main system, and seals open block tops and major cracks. Many block wall homes start with sub-slab suction alone and add wall suction only if needed.
How is the choice made between sub-slab only and wall suction?
The contractor tests how well suction under the slab reaches the walls. If the gravel layer is good and the block cores connect to it, sub-slab suction may be enough. If the walls remain a major entry route, wall suction ports are added and the reasons are explained in writing.
What does the install look like on exposed block walls?
On exposed block, the contractor drills into the cores at chosen points, seals pipe connections to the wall, and runs them to the main pipe. The open top course, cracks, and holes are sealed. Drilling dust is controlled and cleaned up, and the gauge is checked when the system starts.