— Service · 02 / 08

Double-glazed
timber sash
windows.

Slim-line sealed units fitted into period-correct timber profiles — modern thermal and acoustic performance without giving up the proportions of the original sash.

— Why double-glaze

Six reasons London
homes upgrade the glass.

Single glazing is the single biggest source of heat loss and street noise in a period home. Slim-line double glazing solves both without altering the elevation.
  1. 01

    Heat retention

    Up to 70% less heat loss vs. 4mm single glazing.

  2. 02

    Quiet rooms

    36 dB Rw acoustic rating — bus routes feel suburban.

  3. 03

    Lower bills

    Typical first-year saving of £180 — £340 per home.

  4. 04

    No condensation

    Sealed units eliminate winter morning fog — no more rotted cills.

  5. 05

    Period look

    11 — 14mm slim cavity preserves the original glazing-bar shadow line.

  6. 06

    Conservation OK

    Approved for most London conservation areas as like-for-like.

— Glazing specification

Five layers,
one sealed unit.

Every WNDW double-glazed sash uses the same five-layer build. The choice is in cavity gas, low-e coating and acoustic upgrade.
  1. 01
    Outer pane

    4mm Pilkington toughened, optional self-cleaning.

  2. 02
    Cavity gas

    Argon standard · krypton on listed jobs.

  3. 03
    Low-e coating

    Pilkington K · soft-coat selective.

  4. 04
    Warm-edge spacer

    Polymer hybrid — eliminates cold-bridge condensation.

  5. 05
    Inner pane

    4mm Optiwhite for clarity, or laminated for security.

— Double Glazed FAQ

Common questions about
double glazed.

No. We use slim-line 11–14mm sealed units that fit the original glazing-bar profile. From three metres away the elevation is indistinguishable from the original.

Sometimes — it depends on the grading and the local conservation officer. We submit the application as part of the survey at no extra cost.

Most clients see a measurable reduction in the first heating season. Typical saving on a four-bed terrace is £180 — £340 in year one.

Our sealed units carry a 10-year guarantee against seal failure. Warm-edge spacers virtually eliminate the cold-bridge that causes premature failure.

— Ready to start?

Free survey,
fixed quote.

Tell us about the property and we will come back within one working day with a window count, indicative price and the next available survey slot.

Workshop Unit 12, Park Royal,
London NW10 7XF
Service area All London boroughs
+ M25 corridor