Double Glazed Units

Here at Selkent Glazing & Locks we replace double glazed units in Swanley, Orpington, Dartford and the surrounding areas.


What is a double glazed unit?

Double glazed units can be found within UPVC, timber or aluminium window frames or doors. They comprise of two single panes of glass and a spacer bar in between. Contained within the spacer bar are tiny silica balls made from either silica gel or calcium chloride (also known as desiccant). The edge of the panes are sealed creating an insulating void between them, this gap being in the form of a vacuum or it can also be filled with a gas.

Double glazed units often require replacing when they are damaged, are old and the seals go or just when a security upgrade is required. Whatever the reason we have been replacing double glazed units in Swanley, Dartford, Orpington and the surrounding area for many years.



Condensation can appear on double glazed units externally (outside property facing & inside property facing) and internally (within the two panes of glass). Condensation externally (outside property facing) is a natural occurrence and doesn’t indicate a fault with a double glazed unit. This happens mainly in spring and autumn when the glass temperature drops to a low level during the night and the moisture of morning dew condenses against the cold surface of the glass.


Condensation externally (inside property facing) can occur for several reasons. If the temperature in a property or room is low it creates a cold surface that warm air can condense onto. If there is a lack of air circulation within an area then the moisture in the air won’t clear and will again condensate on the windows. Lastly another reason is if there is too much humidity in a room or property.


Condensation in windows

Commonly termed as a ‘blown seal’ or ‘broken seal’, a faulty seal is the main cause of condensation in windows which allows moist air into the void. Faulty seals can occur for several reasons. The main reason being general wear and tear and age. Continuous changes in temperature can also cause fluctuations in the size of the glazed unit, as they expand in warmth and contract in the cold, and over time this can loosen and damage the seals. Other reasons associated with the seal include faulty installation, faulty production methods and strong cleaning products being used to clean the glass eating away at the seal if chemically abrasive.


There are quick fixes on the market to rectify condensation in windows but in order to make your windows energy efficient again then they will need replacing. There are some companies out there who will say you need new windows. This is not necessary unless there are insulation issues within the frame. The good news is that the glass can be replaced without removing the frames making this a cost effective solution whatever the reason for changing them.

Double Glazed Unit security upgrades

A lot of doors and windows are fitted with float glass which is the cheapest glass on the market. This is easy to break and windows with this glass are one of the easiest for thieves to gain entry to a property through. The good news is though that we can upgrade the glass to laminate which is without doubt one of the most secure types of glass on the market.


If you have broken glass or condensation in your windows or would just like a security upgrade then contact Selkent Glazing & Locks for a survey today!

We replace double glazed units in Swanley, Orpington, Dartford and the surrounding areas including

Albany Park, Avery Hill, Barnes Cray, Barnehurst, Bean, Bexley, Bexleyheath, Bickley, Blackfen, Borough Green, Bromley, Bromley Common, Chalk, Chelsfield, Chislehurst, Cobham, Crayford, Crockenhill, Darenth, Dartford, Downe, Dunton Green, East Wickham, Ebbsfleet, Elmstead Woods, Eltham, Erith, Eynsford, Falconwood, Farnborough, Farningham, Fawkham, Foots Cray, Gravesend, Greenhithe, Green Street Green, Halstead, Hartley, Hawley, Hayes, Hextable, Horton Kirby, Istead Rise, Joyden's Wood, Keston, Knockholt, Lamorbey, Lessness Heath, Locksbottom, Longlands, Longfield, Meopham, Mottingham, New Ash Green, New Barn, New Eltham, Northumberland Heath, North Cray, Northfleet, Orpington, Petts Wood, Pratt's Bottom, Ruxley, Sevenoaks, Sidcup, Shortlands, Shorne, Slade Green, Southfleet, South Darenth, Stone, St Mary Cray, St Paul's Cray, Sundridge Park, Sutton-at-Hone, Swanley, Swanley Village, Swanscombe, Upton, Vigo, Welling, Well Hill, Wilmington, Wrotham.

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Selkent Glazing & Locks

Locksmiths, Glaziers, Door and Window Repairs and Double Glazing Repairs with branches in Swanley, Dartford and Orpington.

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