Window Draught Proofing in Dunedin – Sash Brushes, Seals & Healthy Homes Compliance

Draught stopping is also one of the five Healthy Homes standards, which require unreasonable gaps and holes in windows and doors to be blocked in rental properties. Beyond compliance it is simply the cheapest warmth available in a cold house, and an unsealed double hung window has a continuous gap the full width of the sash.

Where the air actually gets in

On a double hung window: the meeting rail where the two sashes overlap, both stiles where the sash slides against the frame, and the gap under the bottom rail. On a casement or awning: around the whole perimeter where the weather seal has flattened.

People often seal the wrong thing. The gap between the frame and the wall lining is a different problem with a different fix, and taping a window shut is not draught proofing, it is losing your ventilation.

Brush pile seal on timber sashes

A shallow groove is routed into the edge of the sash and a nylon brush pile carrier is pressed in. The brush closes the gap while still letting the sash slide, so the window works exactly as before and the seal is invisible with the window shut.

It also stops the rattle, which in a Dunedin squall is often what people rang about.

Do not seal away your ventilation

A house needs air movement or you trade draughts for condensation and mould. Draught proofing closes gaps that leak air when the window is shut. It does not stop you opening the window, and it should not.

On rentals the ventilation standard requires openable windows totalling at least 5 percent of each habitable room's floor area, able to be fixed open. Draught proofing and that requirement work together rather than against each other.

Sealing without losing your ventilation

What to seal and what to leave

Draught proofing closes the gaps that leak air when a window is shut: the meeting rail, the stiles and the perimeter of a casement. It does not mean taping a window closed, which trades a draught for condensation and mould.

The gap between the frame and the wall lining is a separate problem with a separate fix, and sealing the wrong one is common.

How much difference it makes

An unsealed double hung window has a continuous opening the full width of the sash. Two of those in a bedroom is equivalent to leaving a small window permanently ajar all winter.

Brush pile costs a fraction of glazing work, goes in during a single visit, and is usually the first thing we recommend in Dunedin on any house that is cold rather than damp.

The window draught proofing process Window and Glass Repair Dunedin uses in Dunedin

Sealing work is simple to describe and frequently done in a way that does not last, because whatever caused the seal to fail was never addressed.

1. Find where air and water are actually moving

   Window and Glass Repair Dunedin checks the perimeter seal, the meeting rail, the glazing tape and the gap behind the architrave. A draught felt across a room usually comes from one hardened corner you cannot see from either side.

2. Rule out drainage first

   Aluminium frames admit water by design and drain it back out through weep holes. Blocked weeps present exactly like a failed gasket and clearing them costs almost nothing, so it gets checked before any reseal is quoted.

3. Separate draught from cold radiation

   A single glazed window on a Dunedin frost morning feels draughty even when it is perfectly sealed, because you are losing heat to a cold surface rather than to moving air. Window and Glass Repair Dunedin says which one you have, since sealing does nothing for the second.

4. Match the gasket profile exactly

   Profiles vary between joinery systems and a near enough gasket leaves gaps at the corners, which is precisely where most resealed windows still leak. Window and Glass Repair Dunedin matches rather than using whatever is in the van.

5. Strip and clean the rebate properly

   Beads off, old tape and gasket removed, rebate cleaned back to sound material. New sealant laid over old residue does not bond and fails within a couple of seasons.

6. Fit new seals with the corners closed

   New glazing tape and gasket fitted, corners closed rather than butted, beads refitted instead of forced. Compression is checked along the whole seal path with the sash closed.

7. Confirm the fix rather than assume it

   On a leak the opening is water tested again. On a draught the seal is checked for even compression end to end. Leaving without testing is how one window gets two visits.

Why sealing work pays off in Dunedin

In this climate the seals around a window are doing more work than almost anywhere else in New Zealand.

Fifty frost days a year is a hard test

Repeated freeze and thaw cycles harden rubber faster than UV alone. Gaskets that would last twenty years in a mild climate are perished and pulled back from the corners well before that here.

Heating costs make it worth doing

Dunedin sits in the highest insulation requirement zone in the country precisely because heat loss is greater here. Sealing an existing window is the cheapest intervention available and it is usually the first thing worth doing.

Sealing and ventilating are not opposites

A tighter house holds moisture that used to leak out through the gaps. Window and Glass Repair Dunedin raises extraction and ventilation alongside sealing rather than instead of it, because sealing a damp house without ventilating it makes condensation worse.

Healthy Homes still requires openable area

Sealing must not stop a window opening or being fixed open. On a rental that is a compliance matter, not a preference, and a painted shut sash fails the standard even though it exists.

What window draught proofing costs in Dunedin

This is the cheapest meaningful improvement available on an existing window, and the payback in a climate zone 5 city is faster than anything else in this trade.

Per window reseal

Beads off, old tape and gasket out, rebate cleaned and drainage cleared, new tape and gasket fitted, beads back. It is a couple of hours per window and it restores the window to how it performed when it was new.

Draught proofing a sash

Brush seals in the stiles and at the meeting rail on a double hung sash, with no visible change from outside. On a Dunedin villa the meeting rail is the single largest draught path in the house, so this is the highest value line on the quote.

Whole house

Doing every window in one visit brings the per unit cost down substantially, because the visit rather than the materials is most of the price. It also means the house performs as a whole rather than one room at a time.

What it saves

Dunedin sits in the highest insulation requirement zone in the country precisely because heat loss here is greater. Sealing does not change the glass, and it removes the air movement that makes a room feel colder than the thermometer says.

Sealing, draught proofing or glazing: what to do first in Dunedin

In order of cost, and in the order that actually returns the most.

Clear the drainage, first and cheapest

Blocked weep holes present exactly like a failed seal and cost almost nothing to clear. This gets checked before anything is quoted, because a reseal on a window with blocked drainage solves nothing.

Reseal and draught proof, second

Perished gaskets and an open meeting rail are the two largest air paths on most older Dunedin windows. Fixing them is inexpensive, quick and it makes the most noticeable difference to how a room feels.

Retrofit the glass, third

Once air movement is dealt with, the remaining loss is through the glass. Retrofit double glazing at roughly $450 to $800 per square metre is the next step and it is where the larger spend belongs.

Replace the joinery, last

Only where the frames are failing or the work is consented and has to meet climate zone 5. Doing it first, before sealing and ventilating, is spending the most money on the least urgent problem.

Finding the draughts in a Dunedin house

People assume the draught comes through the glass. It almost never does.

The gap around the opening sash

On a casement or awning the seal path runs the whole perimeter. One hardened corner is enough to feel across a room, and it is invisible.

The meeting rail on a double hung sash

Where the two sashes overlap there is usually a real gap, made worse by paint build up stopping them closing properly. It is the largest single draught path in a villa.

Around the frame, not through it

The gap between the joinery and the building framing, behind the architrave. On older houses that cavity is often open to the wall and it is fixed with sealant and reinstated scotia rather than with anything on the window.

Draught proofing and Healthy Homes in Dunedin

There is a tension between sealing a house and ventilating it, and it is worth understanding.

Sealing without ventilating causes condensation

A tighter house holds moisture that used to leak out. Draught proofing works best alongside extraction in the kitchen and bathroom, not instead of it.

The openable area requirement

Healthy Homes requires openable windows, doors or skylights in living rooms, dining rooms, kitchens and bedrooms totalling at least five percent of the floor area, and they have to be able to be fixed open.

Where a window fails that test

Painted shut sashes, seized stays and missing catches all make an opening non compliant even though it exists. Freeing them is usually a hardware job rather than a joinery one.

Window Draught Proofing at a glance

Timber sashes

Brush pile seal routed into the sash edge, invisible when closed

Aluminium

Perished weather seal replaced with new gasket

Fixes

Draughts, whistling, rattling in wind

Healthy Homes

Contributes to the draught stopping standard for rentals

Keeps

Full opening function and the original look of the window