Portsmouth · Hampshire
Secondary Glazing in Portsmouth
We cover Portsmouth and Hampshire for secondary glazing in period homes, flats and listed buildings, with sightlines matched to the original windows.
- PO1
- PO5
- PO2
- Guide from £465
Internal secondary windows in Portsmouth
Low-level secondary glazing is still glazing, so the safety glazing rules for critical locations apply. In England, Approved Document K treats glass within 800mm of the floor as a critical location, so low-level secondary panes should be toughened or laminated safety glass.
Condensation in the gap between the two windows is reduced by making the secondary unit the more airtight of the two. The original window should not be fully sealed, so any moisture that gets into the cavity can escape outside rather than being trapped against the glass.
Secondary glazing leaves the original window untouched and fits a second, independent window inside it. The air gap between the two works with the glass to reduce noise and heat loss. In most cases the installation can be taken out later without damaging the historic window or reveal.
Opening styles include vertical sliders that line up with sash window meeting rails, horizontal sliders for wide openings, hinged casements, lift-out panels for windows that are rarely opened, and fixed panes. The choice depends on how you use the window, cleaning access and fire escape needs.
Included as standard
- Survey of each window, reveal depth and sightlines
- Fitting, sealing and checking every opening panel
- Made-to-measure slim aluminium frames and glass
- Advice on opening style, glass and fire escape
Portsmouth at a glance
- Postcodes covered
- PO1, PO5, PO2 and the surrounding area, including Gosport, Fareham and Ryde
- Coast
- Portsmouth is about 2 km from the coast or a tidal estuary, so salt air and wind-driven rain are worth planning for. Coastal properties often have older windows exposed to wind-driven rain and draughts. Secondary glazing adds a sealed inner layer that reduces draughts and cold, while the original window keeps out the weather and its condition is protected from inside.
- Daylight and sun
- In Portsmouth the midwinter sun reaches about 16° above the horizon at noon, with roughly 7.7 hours of daylight, rising to about 63° and 16.3 hours in midsummer. Secondary glazing adds an extra layer of glass, which slightly reduces daylight. Low-iron or clear low-E glass keeps light loss to a minimum, while on sunny elevations solar control glass can help reduce overheating in rooms with large windows.
- Access and setting
- In city centres and busy streets, acoustic secondary glazing is a common response to traffic, rail and nightlife noise. Flats, listed buildings and conservation areas often limit external changes, which makes internal secondary glazing a practical option.
- Rules in England
- Approved Document K requires safety glass in critical locations in England: glazing in doors and in side panels within 300 mm of a door, up to 1500 mm above floor level, and any glazing in walls or partitions up to 800 mm above floor level.
Guide prices in Portsmouth
| Typical job | Guide price inc VAT |
|---|---|
| Slider, 900 × 1200 mm | £465 – £595 |
| Slider, 1200 × 1600 mm | £665 – £845 |
| Acoustic glass, 1000 × 1400 mm | £675 – £865 |
Get a guide price for your size
Approved Document B covers escape windows. Where an existing window is an escape route, typically in first-floor bedrooms, its replacement should give at least the same escape opening as before.
Options to choose between
Horizontal sliding
Panels slide sideways, suiting wide casement windows and openings where you need regular access for cleaning or ventilation.
Lift-out panel
A lightweight panel that lifts out of its frame, for windows rarely opened, giving a slim and economical secondary unit.
Hinged casement
Panels open inwards like a door, giving full access to the original window, and can be chosen for escape windows.
Secondary Glazing in Portsmouth: questions
Does secondary glazing need safety glass?
It does in critical locations. In England, glass within 800mm of the floor, glass in doors and glass near doors are critical locations under Approved Document K, and these apply to secondary glazing too. Low-level secondary panes should be toughened or laminated safety glass. The surveyor checks each window during the survey.
Which opening style should I choose?
Choose based on how you use the window. Vertical sliders suit sash windows and keep meeting rails aligned. Horizontal sliders suit wide windows. Hinged panels give full access for cleaning and escape. Lift-out and fixed panels suit windows that are rarely or never opened, and give the tightest seal for noise.
Will secondary glazing cause condensation?
It can, if the original window is sealed tighter than the secondary unit, because warm, moist room air then gets trapped in the cavity. The secondary unit should be the more airtight of the two, and the original window should not be fully sealed. Opening the secondary panel lets room air into the cavity, so close it again afterwards.
Is secondary glazing as good as double glazing?
It depends on the goal. For noise, secondary glazing is often more effective, because the wider gap between the two windows reduces sound better than the narrow cavity of a sealed unit. For heat, a well-sealed secondary unit with low-E glass significantly improves a single-glazed window. It also keeps original windows, which matters in listed buildings.
Do you cover Portsmouth for secondary glazing?
Yes. We can quote for secondary glazing across Portsmouth and the surrounding Hampshire area, including postcode districts PO1, PO5 and PO2, and nearby Gosport, Fareham and Ryde. Start with your postcode on the quote form and a glazier will arrange a free survey before giving you a written quote.
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