Home>Discussions>PLUMBING>INSTALLING cast iron radiators: How to handle piping up to 2nd floor?
2 posts / 0 new
Last post
INSTALLING cast iron radiators: How to handle piping up to 2nd floor?

We are installing some cast iron (hot water) radiators in our historic home. My only concern is running the piping up from the basement to the second floor, as the pipes will need to go through our crown molding on the first floor.

Any suggestions on how to handle this? Or how to avoid the situation altogether?


Re: INSTALLING cast iron radiators: How to handle piping up to 2nd floor?

Not sure I completely understand your post & I wonder if the historic home is made of standard 2 x 4 wood wall studs, or some other material; in most cases there is a narrow empty space inside each wall (wall cavity) that is used to drill a 1" hole thru the wood studs from the basement boiler piping, thru the wall cavity, to the 2nd floor to connect the boiler piping to the radiators; flexible hi temp plastic 3/4" PEX piping is then threaded thru the wall cavities up to the 2nd floor to make the connection and attached to the SUPPLY side of the radiator, or series of radiators; a second 3/4" PEX tube is attached to the RETURN side of the rad, or set of rads, & returned to the boiler RETURN side thru the wall cavities to complete the loop (often attached to zone valves in the boiler room to make the 2nd floor a separate zone with its own thermostat).

Sometimes there are horizontal 2 x 4 pieces of wood connecting the vertical 2 x 4 framing studs inside the wall cavities known as FIRE STOPS, which would make it impossible to run a flex piece of PEX up to the 2nd floor; in such a case a decision would have to be made whether to open up the walls at the fire stops & drill a 1" hole thru them to allow the PEX tubing to reach the 2nd floor; another alternative to this is to run a SUPPLY PEX or copper line up a corner of the 1st floor room, then a RETURN copper or PEX line down another corner to complete the 2nd floor loop, and then BOX IN the corner/supply lines with 3/4" pine boards & paint them an acceptable color to complete the job.

If there is more than one 2nd floor rad to be connected up (say, 3 or 4) then this would make for unsightly pipe connections to each rad on the 2nd floor before reaching the 2nd floor RETURN line; in such a case a much more attractive appearance could be had by using baseboard heating elements, where most of the piping/heating elements are enclosed in the steel enclosures & makes for a better appearance; however, I'm a big fan of cast iron radiators, and strongly recommend keeping & using them as they give off a superior quality level of heat by both radiation & convection.

Any supply/return piping that is not installed within the wall, or boxed into a corner will be unsightly, especially going thru the crown molding, if I understand your post properly.

Hope this helps.

Sponsored Stories

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.