We are having an enclosed porch, which was badly done long before we bought the house, remodeled. We are replacing baseboard heating with a hot-water radiant-floor system. The contractor will first put Tyvek over existing plywood, which is over a concrete slab, then lay 2-by-4's on their sides, then lay insulation board in between, then more insulation board with the heating coils, then plywood to stabilize the floor, then concrete to level the floor, then finish it with ceramic tile. Does this seem like a reasonable system as far as insulation, yet allowing for conduction of heat upward and into the room?
This is a tough one because you say it is a hot-water system, but the installation method sounds more like what one would do with radiant floor heating mats, only because your letter inspired me to consider a combination solar-operated heating mat system for our greenhouse (although excessive moisture would likely create safety issues).
Hydronic systems circulate water from a boiler or water heater through loops of polyethylene tubing, often called by the brand name Pex, but there are others.
Tubing is typically installed on top of the subfloor in grooved panels or snap-in grids; clipped into aluminum strips on the underside of the floor; or embedded in poured concrete, or a lighter, concretelike material in bathrooms or kitchens especially.
When the Remodelers Show was in Philadelphia 11 years ago, the featured rehabbed townhouse on South Second Street had hydronic radiant heat on all floors, thanks to the flexibility of polyethylene tubing.
In the past, radiant floor heating required cast-iron pipes, and use was limited.
The contractor’s insulation system, as you describe it, appears proper. I don’t like using plywood, exterior grade or otherwise, as a subfloor for tile when weight isn’t an issue. The porch already sits on a concrete slab.
In addition, hydronic systems, or so the experts say, are more cost-effective for whole-house use, while single-room systems are best served by heating-mat systems.
Have you asked for more than one estimate? Getting another bid or two before you proceed might clear up any doubts you might have.
Robert Naujoks of Marion, Iowa, offers advice on old-house window replacement.
In the last 10 years, Naujoks has replaced windows in his 100-year-old house with double-E glass.
Instead, he used tilt-sash replacement kits that insert into the existing opening. Simply remove the old sash, take out the window weights, put insulation in that open space, then add metal “jamb-liner clips” to attach a vinyl insert with a track system for holding the windows. The insert pops right onto the metal clips.
The windows are then inserted in the track, just like modern-day windows. The frames are wooden and can be obtained primed or with aluminum exterior surfacing. They are tight and do not rattle. When the window-stop molding is replaced, the jamb liner is hidden.
Questions? E-mail Alan J. Heavens at firstname.lastname@example.org or write him at The Inquirer, Box 8263, Philadelphia, Pa. 19101. Volume prohibits individual replies.