HI FROM RILEYMAN, CAN YOU DOUBLE GLAZE A TRADITIONAL HARDWOOD MAHOGANY FRONT DOOR CONSISTING OF 9 SMALL 8"X9" SINGLE GLAZE GLASS PANELS AND 4 WEDGE SHAPED PANES OF GLASS FORMING THE BOW. DOOR ABOUT 20 YEARS OF AGE STILL A1 CONDITION, HEAT LOSS THROUGH LARGE AREA OF GLASS ,WHAT ARE THE OPTIONS WITHOUT RESORTING TO SECONDARY DOUBLE GLAZING WHICH WHAT I,VE SEEN OF LOOKS HEATH ROBINSON!. LATHS THAT HOLD GLASS INTO PLACE-WILL THEY HAVE TO BE REMOVED AND A COMPLETE DOUBLE GLAZED GLASS UNIT FITTED INTO THE OPENING. IS IT VIABLE. IN ANTICIPATION
While this is not the answer to asked for...........
I double glazed an identical door four years ago, simply by fitting a sheet of glass across the inside.
Much to my surprise it works perfectly recording similar temperatures to my double glazed windows and it has never had any condensation between the glass or on the inside hall glass.
Compared to my front door, a modern plastic door with fancy double glazing, that is always covered in condensation when the outside temperature drops below 7C, it has been a satisfactory result.
Realistically The thinnest you can make a double glazed unit is 14mm ie 2 panes of 4mm glass and a 6mm spacer. You then need 3mm per side for bedding compound, so without the beads you need 20mm minimum plus a bead of 12mm each, you normally don't have space for this in the rebate of a mass produced door. Anyway 6mm air gap sealed units are pretty much worthless in heat saving terms. :? :? :?
I agree with that. A gap over 16mm does not improve insulation.
As a matter of interest I measured the outside temperature of all my windows on Friday 18.12.09 these have various gaps being of different ages.
Two of my windows with an estimated gap of 12.5mm measured at surface minus 14 and minus 15 degrees C. With an internal surface temperature of plus 13C and a room temperture of 18.9C........interesting.