Benefits of Secondary Glazing
Insulation - Standard Secondary Glazing greatly increases the Thermal Rating
of the Window - Low "E" Glass can be used to equal or better the Thermal Performance
achieved by Replacement Sealed Unit Double Glazing - Saves Energy - Reduces Heating
Bills - can meet the Requirements of Building Regulations Document "L" for the
Thermal Standard of New & Replacement Windows - Improved Energy Rating for the
new Energy Performance Certificate for the Home Buyers Pack.
Sound Insulation - Standard Secondary Glazing achieves
a significant reduction in Noise entering from Outside - Specialist Glasses, such
as Stadip ® Silence Laminated Acoustic Glass, are especially effective against
Road, Aircraft, Rail & in fact any type of Noise.
- Installing Secondary Glazing is much Cheaper than Replacing Windows.
Security - Standard Secondary Glazing adds considerably
to Security - it can only be Opened from Inside - the addition of Toughened or
Laminated Glass & additional Locks will Further Increase Window & Door Security.
Dust & Rattles - Because the Internal Secondary Glazing
is Fully Sealed there is very little Air Movement within the Cavity, thereby virtually
eliminating the ingress of Dust & Cutting Out any Rattling of the Primary Window.
Draughts - No more Draughts from Windows and Doors once they have been
fitted with Secondary Glazing!
Carpets & Soft Furnishings - Where Secondary Glazing with Laminated Glass
is Specified it Protects Carpets & Soft Furnishings by Filtering Out the Colour
Fading effects of UV Light.
- Secondary Glazing can Provide all of the Heat & Noise Insulation that Modern
Living Demands whilst Protecting the Character of Your Home by Retaining the Original
Timber or Metal Windows.
Buildings, Conservation Areas & Listed Buildings - Other than in very exceptional
circumstances Secondary Glazing is Accepted & indeed Welcomed by Planning Officers
as a Much Better Alternative to Replacing Windows & Doors in Conservation Areas
& Listed Buildings.
- Maintenance - Maintenance for
Secondary Glazing is minimal.
Note of Caution
When fitting Secondary Glazing it is neither Advisable
nor Necessary to Seal Up, Double Glaze or Draught Exclude Primary Windows or Doors,
for the following reasons:
existing Windows & Doors will not Significantly or Noticeably Improve either Thermal
or Noise Insulation.
Windows & Doors have been doing their job Satisfactorily for Many Years, in some
cases for as Long As 100 Years or More - they were Not Designed to be Fitted with
Draught Excluders, Brush Seals or in fact any type of Window Seal - doing so is
likely to Stress & Weaken a perfectly good Window or Door & Shorten its' Life
Similarly, fitting Sealed
Units to existing Casements & Fanlights will Critically Reduce the depth of the
Original Frames & severely Weaken the Joints - a Sealed Glass Unit will typically
be between 2 & 3 Times the Weight of the original Single Glass and this will Critically
Strain the Joints, Hinges, Handles & Locks of old Casement Windows.
For Traditional Sash Windows the problems are more acute, the actual Sashes are
far too thin for a Modern Specification Sealed Unit so generally a unit with a
6mm Cavity will be fitted, which will not add much to the Insulation - additionally
Staff & Parting Beads will need to be Removed & Refitted or Replaced to Re-cord
the Sashes and the Boxes will need to be Opened to Hang Heavier Weights - this
is all Costly, Messy Work, for Little or No Benefit & the Window will Require
Complete Redecoration upon Completion.
The very Minimal Air Movement within the Cavity between the Secondary Glazing
and the Primary Window or Door Prevents Condensation from forming in the gap between
them - this protects the Primary Window from Condensation Forming, Condensation
laying on Glazing Bars and Heavy Condensation running on the Vertical Surfaces
& gathering on the Joints with Horizontal Surfaces, which if left unattended will
probably cause mould & rot.
particularly important if the Primary Window or Door contains any Traditional
Stained Glass - if this is the case then consideration should be given to Fitting
a Trickle Vent to the Secondary Glazing in order to Further Ventilate the Cavity
- Condensation can be Very Damaging to Both the Stained or Painted Glass & also
to the Lead, Copper or Zinc Foil Cames & Securing Wires and also to the Cement
(Sealing Compound) used to Glaze the Coloured Glass into the Metal Cames & Surrounding
secondary glazing inside your present windows - make sure that the panels can
be lifted off or hinged so that you can open the windows easily and clean them
safely. Only fit draught proofing to the secondary panels - so that external air
will prevent condensation forming in the gap between the windows and secondary