If you're thinking of purchasing double glazing, it is always useful to know something about the product. We have listed some FAQ's on double glazing together with some unbiased answers to help you make your decision
Click a question to reveal an answer.
Q. The rear of my house and garden faces south facing, and is very bright and hot in the summer, could you advise what would be best, a garden umbrella or a patio awning?
A. I would suggest a patio awning as these are ideal to protect you from the sun and cover a larger area. Another added attraction is that they can be used at night for entertaining as they can be supplied with lighting and when it's bedtime you just press a button and your patio awning will fold up ready for tomorrow to find out more on patio awnings follow me to
Q. I live near to a busy road that runs down the side of my property so sound installation is very important to me, are there any special glazed units that lower the sound more than standard sealed units?
A. Yes, by fitting double glazing to your property will certainly improve the sound proofing. I would suggest that you have B rated sealed units with one side laminated glass as this would drastically cut out the noise from outside
Q. I am thinking of having double glazed sash windows installed in an old terraced property, which currently has sash box windows. Having received three quotes, I have also received three views on whether the whole sash box should be removed or the new units simply fitted within the existing sash box, leaving the internal wood in place. One double glazing window company said. The whole box sash should be completely removed to ensure a good job, the second said there was no need as the wood was original and was in good condition, the third said it doesn't matter, but fitting within the sash box will be cheaper. Please could you tell me who's right?
A. When replacing box sash windows both methods can be used, some companies believe leaving the original 'box' in place and fitting the new double glazed sash window within the existing box sash should be perfectly acceptable providing the timber is in good condition plus it will have all the original moulding. Complete replacement is the best option in our view as if the old timber is rotten this would be false economy. At Falcon we remove the complete boxed sash stud out inside plasterboard and skim including fitting a window board. This way it is a much better job and all that is left is the redecoration inside. Alternatively we can fit vertical sliding sashes which are becoming more and more popular and affordable. In our view these are by far the best option but are slightly more expensive and look just like the old box sash windows including the decorative horns.
Q. I live in a conservation area, and I am considering having PVC-u double glazed sash windows fitted to replace my old metal windows, are there any restrictions?
A. Yes there could be restrictions if you live in a conservation area or have a listed building. My experience has found it is best to discuss this with the local conservation or planning officer what you would like to do and they can let you know whether it's possible
Q. What is tempered or safety glass?
A. Tempered glass when broken shatters into many small fragments and prevents major injuries. Due to these characteristics tempered glass is used traditionally in applications requiring increased strength such as Patio doors, French doors or UPVC windows. However tempered glass should receive the same care as annealed glass.
Q. Why do I get condensation on the outside of my Windows?
A. The "problem" is caused by the fact that the Low E insulating Glass is doing its job so well and reflecting heat back into the room. You would normally expect reduced or no condensation once double glazing was fitted
External condensation (dew) can occasionally occur on highly insulated units in temperate climates. Such occurrences will only happen on cloud-free nights when there is little or no wind and usually when a warm front follows a dry spell. The amalgamation of quite a few factors, namely external air temperature, localised microclimate and the thermal transmittance of the glazing itself may all add to the formation of external condensation.
Q. What is the best option - toughened glass or laminated glass?
I have a child - am I right in saying that toughened glass is more dangerous if smashed? Is one more secure than the other?
Both Toughened and Laminated glasses are forms of "safety" glass. People often presume toughened glass is extra strong glass.
In our opinion "break safely glass" as they are both known are both safe.
Toughened glass breaks into very small pieces which are very hard to get cut from where it's laminated glass cracks when broken as there is a thin layer of Perspex in between two panes of glass. Laminated glass is "thicker" usually 6.4 mm and as such will offer better insulation and is quieter inside as well due to the different thicknesses of the glass. It is also harder to break in due to the thin plastic inside the glass
However this thicker glass is also "heavier" which will in turn mean greater "wear and tear" on opening windows and doors. It is also slightly more expensive than toughened glass.
This is probably one of the reasons it's not so widely specified in conservatory construction
Are you having a problem with condensation on the outside of your windows in cold winter months?
Download a condensation technical data sheet
Download a condensation booklet
Double Glazing Quality of Vision
Click here to download Falcon Windows Quality of Vision Leaflet
Standards and Regulations
Relevant British & European Standards
- BS 5588: Part 1:1990 - Fire precaution in the design, construction and use of buildings
- BS 6206: 1981 - Impact performance requirements for flat safety glass and safety plastics for use in buildings
- BS 6262: 1982 - Glazing for buildings
- BS 6375 - Performance of windows Part 1. Classification for weather tightness Part 2. Specification for operation and strength characteristics
- BS 6399: Part 2:1997 - Loading for buildings Part 2. Code of practice for wind loads
- BS 7412: 1991 - Plastics windows made from PVC-U extruded hollow profiles
- BS EN 12608: 2003 - Unplasticised polyvinyl chloride (PVC-U) profiles for the fabrication of windows and doors - Classification, requirements and test methods
- BS 7950: 1997 - Specification for enhanced security performance of casement and tilt/turn windows for domestic applications
- BS 8213 - Windows, doors and roof lights
- Part 1 (1991). Code of practice for safety in use and during cleaning of windows and doors (including guidance on cleaning materials and methods)
- Part 4 (1990). Code of practice for the installation of replacement windows and door sets in dwellings
- BS EN ISO 10077-1:2000 - Thermal performance of windows, doors and shutters - Calculation of thermal transmittance
- Part 1. Simplified method
- All the above BSI documents can be ordered from 'BSI Customer Services Department on 020 8996 9001'
BPF Windows Group Publications
- 323/1 COP for the reinforcement of high impact modified PVC-U windows and doors
- 351/1 Guidelines for the use of PVC-U windows and frames in commercial/light industrial applications
- 356/1 COP for the installation of PVC-U windows and door sets in new domestic dwellings
- 357/1 Replacement windows and planning law
- W362/1 Code of practice for the survey and installation of replacement plastics windows and door sets
- W363/1 Guidelines for the selection and application of fasteners for the manufacture of plastics windows and door sets
- W364/1 Guide to the specification and use of plastics windows and door sets Guide to Building Regulations, Building Control and FENSA (CD or booklet)
- All the above BPF documents can be ordered from 'BPF Publications Sales Department on 020 7457 5000'
The following is a list of regulations applicable to England and Wales.
- Part A (England & Wales): Structure The revised edition of this document has been distributed for comment
- Part B (England & Wales): Fire Safety
- Part E (England & Wales): Resistance to the passage of sound
- Part F (England & Wales): Means Of Ventilation
- Part J (England & Wales): Heat Producing Appliances
- Part K (England & Wales): Protection From Falling, Collision And Impact
- Part L1 & L2 (England & Wales): Conservation Of Fuel And Power Part M (England & Wales): Access And Facilities For Disabled People
- Part N (England & Wales): Glazing In Relation To Impact, Opening And Cleaning
The following is a list of regulations applicable to Scotland.
- Part C (Scotland): Structure
- Part D & E (Scotland): Fire Safety
- Part F (Scotland): Heat Producing installations and storage of liquid and gaseous fuels
- Part H (Scotland): Resistance to transmission of sound
- Part J (Scotland): Conservation Of Fuel And Power
- Part K (Scotland): Means Of Ventilation Part P (Scotland): Miscellaneous hazards
- Part T (Scotland): Facilities For Disabled People
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