The radiant tube layout for the entire first floor calls for 8" spacing so we can get two tube runs per joist bay. To pass the tubing from one bay to the next requires cutting a hole through each joist at one end.

Jeff cut a 1 1/4" hole which made it easy to slide our 5/8" (outside diameter) tubing through.

The bedroom will be on its own zone and will require only one loop of tubing. But it will use up almost an entire 300' roll. Feeding the tubing through the loop pattern is tedious - unroll about 20 feet of tubing, feed it through one end of a bay, move the ladder, feed the tubing through the other then, move the ladder back, then repeat. This gets pretty messy, with tubing hanging and laying all over the place.

Jeff decided to start feeding the tubing from the return end. After he got a couple of bays filled, John helped him feed the rest of the tubing through the remaining bays. At one end (right), the tubing passes through the joist holes. At the left end, the tubing will turn around in the same bay and head back to another joist hole. This picture shows all of the mini loops hanging from each bay.

Without any tracking installed to hold the tubing in place, there seems to be no order to the layout.

After two lengths of aluminum tracking installed, things start to take shape. The return line is on the right. Directly above the joist to the right will be the bedroom wall.

Here's the 8"-spaced track pattern.

This picture shows the tubing loops passing through the joist holes. The bends are very tight, but within tolerances for the 1/2' tubing we're using.