Draughty windows — diagnosed and fixed across Caerphilly
Most Caerphilly enquiries about draughty windows arrive with the same underlying question: whether this is a small job or the start of a big one. On the stone-fronted terraces, post-war semis around the castle and newer estates out toward Bedwas that dominate Bedwas, Trethomas, Machen, the answer usually depends on the age of the frame rather than the severity of the symptom. Locally the complicating factor is wind-driven rain off the mountain ridge, which shortens the life of exactly the components this fault attacks.
What you'll notice first
- a curtain that lifts slightly on a windy night with the window shut
- a cold ribbon of air along the sill or down one jamb
- whistling from a specific corner when the wind sits on that elevation
- the room never quite holding heat despite the radiator running
Your realistic options
New EPDM gasket run into the existing channel and fresh external mastic to the reveal. Cheapest fix and often the only one needed.
Friction stays replaced or re-shimmed, keeps moved so the cam pulls the sash squarely onto the seal all the way round.
The right call when the profile is thin-walled 1990s uPVC, corner welds have opened, or the frame itself has bowed — at that point no amount of sealing restores compression.
We'd rather adjust than sell. If a sash can be pulled back onto its seal with new gaskets and a hinge tweak, that's a short visit and a small bill. Replacement earns its place when the frame has lost its geometry, when single glazing is still in place, or when you're solving heat loss across a whole elevation rather than one opening.
What actually causes it
- 1the rubber gasket has gone hard and flat, so the sash no longer compresses onto it
- 2hinges have sagged and the sash is closing tight at the top and loose at the bottom
- 3the keeps are worn so the lock pulls the sash in less than it used to
- 4the external mastic between frame and brick has shrunk and cracked away
- 5trickle vents left permanently open and mistaken for a draught
What we typically find on survey
- One of the sealed units carries the previous installer's phone number etched on the aluminium spacer bar.
- The stay arm on the top vent has bent and no longer sits into its rest bracket cleanly.
- The internal reveal plaster is spalling under the cill where condensation has run for years.
- The hinges are all dropped one notch from level, taking the sash out of square against the outer frame.
- Silicone at the outer perimeter has hardened, cracked, and lifted at the head — water tracks behind it in heavy rain.
- The internal beads pop out with a chisel and a tap, but the external glazing gasket is bonded solidly to the frame.
How we actually carry out the work
- The multipoint hooks are lightly greased after fitting, before the door is closed for the first time.
- The site tidy happens twice per day, not once at the end, so brick dust doesn't track through the house.
- The multipoint gearbox is thrown by hand before the frame goes in — a factory fault at that point is a five-minute fix.
- The internal cill is scribed with a coping saw against the reveal plaster, not butted flush with a caulk joint.
- The finished elevation is photographed from the pavement and uploaded to the office job file as sign-off record.
- The frame reinforcing steel is confirmed inside the top rail before the transom fixing is chosen.
What we check on survey
- we run a hand round the closed sash on a windy day rather than guessing from the inside
- paper test on the seal line: if a sheet pulls out freely with the window locked, compression has gone
- we check whether the draught is actually the trickle vent doing its job
- we look at the external mastic joint, which fails long before most people notice
How it's priced
Gasket and adjustment work is charged as a short visit. Replacement is priced per opening by size and configuration — a small fixed light is a fraction of a three-part bay. We price both routes on the same quote so you can see the gap.
How urgent is it? Worth acting on before winter. Draughts cost you continuously through the heating season, and a sagging sash left uncorrected wears the hinges and keeps faster.
Why this comes up in Caerphilly
- Council
- Caerphilly
- Postcodes
- CF83
- Main route
- A468
- Nearest town
- Cardiff (7 mi)
Around Bedwas, Trethomas, Machen the recurring local factors are wind-driven rain off the mountain ridge; noise from the A469 corridor; tired 1990s-era double glazing failing at the seals. Commercial neighbours such as Pontygwindy Industrial Estate and Bedwas House Industrial Estate change the exposure again on the elevations that face them, and the Caerphilly County Borough Council area sets the standards any replacement work is signed off against.
- Bedwas
- Trethomas
- Machen
- Energlyn
- Llanbradach
- Abertridwr
- Rudry
- Nelson
- Ystrad Mynach
- Senghenydd
- Aber Valley
Stopping it coming back
- silicone spray on the gaskets once a year keeps them supple instead of chalky
- oil the hinges and locking mechanism so the sash keeps pulling in square
- don't paint over the gasket — paint stiffens it and it stops sealing
Draughty Windows — questions we get asked
Will new windows definitely stop the draught?
Only if the frame is the cause. If the draught is coming from the plaster reveal, an unsealed lintel or a gap behind the sill, new windows fitted to the same opening can leave it exactly as it was — which is why we check the reveal before quoting.
Is draught-proofing tape a real fix?
It's a stopgap. Self-adhesive foam compresses permanently within a season and gums up the gasket channel. A proper replacement gasket costs little more and lasts years.
Should I block the trickle vents?
No. They're there to manage moisture, and closing them permanently is the fastest way to create condensation and mould on the reveals.
Do you cover draughty windows across the whole of Caerphilly?
Yes — CF83 and the surrounding villages, including Bedwas, Trethomas, Machen, Energlyn. Easy in via the A469, and we're 10 minutes from the A470 for vans loaded with full-house glass.
Is draughty windows more common on Caerphilly properties?
It's shaped by the local stock. With stone-fronted terraces, post-war semis around the castle and newer estates out toward Bedwas, plus wind-driven rain off the mountain ridge and noise from the A469 corridor and tired 1990s-era double glazing failing at the seals, the components involved in this fault tend to age faster here than on sheltered inland new-builds.
If replacement is the answer
10-year product guarantee, 2-year fit warranty, lifetime hardware servicing
10-year product, 2-year fitting, lifetime hardware servicing
10-year sealed unit guarantee, 10-year frame, 2-year fitting
10-year product on every frame, 2-year fitting on the whole package, single point of contact
Other faults we see in Caerphilly
Fog between the panes means the sealed unit has failed — the glass can usually be swapped without touching the frame.
ReadFrench doors are a pair, so the fault is usually in how the two leaves meet rather than in either leaf on its own.
ReadA door that needs lifting, shoving or a second attempt to lock is warning you before the gearbox fails completely.
ReadFull background on draughty windows
The main guide covers the mechanics of this fault in more depth, without the Caerphilly context.
Read the Draughty Windows guide →Let's make your house feel more like home.
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