Condensation On Windows in Caerphilly
Market town with the castle as the centrepiece — a mix of stone period stock and modern estates. That mix of housing is why we won't quote window condensation in Caerphilly off a photograph. A Bedwas property and a newer Machen build present the same symptom for different reasons, and the fix differs accordingly. Easy in via the A469, and we're 10 minutes from the A470 for vans loaded with full-house glass.
What actually causes it
- 1internal condensation: warm damp air meeting the coldest surface in the room, which is nearly always the glass
- 2drying laundry indoors, unvented tumble dryers and lidless pans adding litres of moisture a day
- 3extractor fans that run but vent into a loft rather than outside
- 4sealed unit failure, if the water is genuinely between the panes and can't be wiped
- 5external condensation on the outer pane, which is a sign the glass is insulating well, not badly
Your realistic options
Trickle vents opened or retrofitted, extractor performance checked, and a fifteen-minute cross-purge in the morning. Free or cheap, and it fixes the majority of internal condensation.
A low-E soft-coat unit with a warm-edge spacer raises the internal glass surface temperature, so the room's moisture no longer finds a cold enough surface to condense on.
Where the condensation is forming on the frame or the reveal rather than the glass, the cold bridge is the profile or the fitting detail, and replacement with a multi-chamber frame and a properly insulated reveal is the durable answer.
We won't sell windows to solve a laundry problem. If the water is on the room side and the frames are sound, the honest advice is ventilation and heating pattern first. Where the glass surface is genuinely running cold and the units are old single-coated stock, upgrading the glazing does measurably move the dew point.
Stopping it coming back
- run the extractor for ten minutes after a shower rather than switching it off with the light
- keep internal doors to bathrooms and kitchens shut while moisture is being generated
- leave a gap behind wardrobes on external walls so air can move across the cold surface
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
What we check on survey
- we ask which face the water is on before anything else, because it changes the entire diagnosis
- we check whether extractors actually terminate outside
- we look for mould patterning at the top corners, the classic cold-bridge signature
- we note whether the affected rooms are the ones generating moisture
How it's priced
Retrofitting trickle vents to existing sashes is a small job. Upgrading to low-E argon units is priced per opening. A full-elevation replacement is a different order of cost and only worth quoting once the ventilation side has been ruled out.
How urgent is it? Deal with persistent internal condensation quickly — sustained surface moisture grows mould on the reveal, and mould on plaster is a decorating job on top of the original fix.
What you'll notice first
- water pooling on the inside sill each morning and running onto the plaster
- black spotting appearing on the reveal or the top corner of the frame
- dew on the outside face of the glass at dawn that burns off by mid-morning
- the bathroom or kitchen window streaming while the rest of the house is dry
What we typically find on survey
- The letterplate is a straight through-plate with no anti-snap flap — visible from outside in the hallway.
- A homemade timber threshold has been screwed to the concrete cill in front of the patio door.
- The frame drainage slots at the bottom are clogged with debris, so rainwater sits inside the chamber.
- Condensation runs down the inside of every north-facing pane between October and March.
- Wet-set fixings through the outer frame have rusted and stained the surrounding brick.
- The internal glazing bead sits proud of the frame by 1.5mm, so the seal at the top corner has failed first.
How we actually carry out the work
- Fixings are set at the manufacturer's spacing, not evenly spaced by eye — the corner loads matter.
- The perimeter airtight tape is applied over the frame flange in a single unbroken run around all four sides.
- The perimeter tape between frame and reveal is a compressible foam tape, not a plain butyl strip.
- The glazing bead is tapped in with a rubber mallet, not a metal claw — the profile marks otherwise.
- The cylinder key gets a keyring immediately, so it does not sit unnoticed in a jacket pocket for the day.
- The multipoint keeps get a smear of grease inside the pocket before the door is closed for the first time.
Condensation On Windows — questions we get asked
Why do my new windows have more condensation than the old ones?
Because they're airtight. Old leaky frames ventilated the house accidentally. New windows stop that, so the moisture you were always generating now has to leave deliberately through vents and extraction.
Condensation on the outside of the glass — is that a fault?
No, the opposite. It means so little heat is escaping through the unit that the outer pane drops to dew point overnight. It's a sign the glazing is working.
Will triple glazing stop condensation?
It raises the internal glass temperature further, so the glass is less likely to be the coldest surface. It doesn't remove the moisture — ventilation still has to do that.
How quickly can someone look at it in Caerphilly?
We run the A468 corridor regularly, so a survey in Caerphilly is usually available within the week and the written quote follows within 24 hours of the visit.
Do you cover window condensation 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.
If replacement is the answer
Other faults we see in Caerphilly
Most of the heat leaves through the roof and the frames, so that's where the money should go first.
ReadFog between the panes means the sealed unit has failed — the glass can usually be swapped without touching the frame.
ReadMost break-ins through glazed openings exploit the cylinder or the keeps, both of which are upgradeable in an afternoon.
ReadFull background on window condensation
The main guide covers the mechanics of this fault in more depth, without the Caerphilly context.
Read the Condensation On Windows guide →Let's make your house feel more like home.
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