uPVC Windows on a 1930s semi in Caerphilly
If you've got a 1930s semi-detached on your hands in Caerphilly, the recurring problem when quoting uPVC windows is original steel-frame Crittall casements replaced piecemeal, so no two windows match. Misted units, condensation pooling on cills, cold-draught complaints and EPC ratings dragging properties below E is the paired issue you'll usually hear about at the same visit. Our spec here is A+ rated multi-chamber uPVC with 28mm argon-filled double-glazed units. Stained-glass fanlights above the door can be re-set into a modern composite slab if intact, giving continuity across the swap. Stone walls hold thermal mass but radiate cold at the reveal edge; deep frames pull the cold plane further from the room. Roof canopies are usually mono-pitch and shallow — scaffold clearance rarely exceeds 2.1m above the frame head. New-build reveals are square to within 3mm — packing is minimal and the frame lands true first time. Estate roof pitches shed water clear of the head of the frame — lead flashing renewal is rarely required. South-facing seafront elevations fade dark PVC foil visibly within 8–10 years; lighter foils hold their colour twice as long. Original bay leaded-light casements are worth an offer — restorers pay reasonable money for intact panels rather than skip them. Slate roofs above the front elevation shed water tight to the frame head; a lead flashing detail rarely needs replacement, just re-dressing. Render around the frame edge is often 60s scratch-coat — patch and re-paint the same visit rather than mask. Oil-heating running costs make triple-glazing an easier upsell on barn conversions than on urban stock.
Reveal and install detail
- → The bay is a load-bearing corner — steel-reinforced mullions replace the original steel-frame casement.
- → Cavity walls take a straightforward frame fixing but the internal render is old-school lime, brittle to lever.
Method: old frames removed cleanly, new units sat on hardwood packers, expanding foam plus internal trims for a draught-tight seal.
Guarantee: 10-year product guarantee, 2-year fit warranty, lifetime hardware servicing.
Who's asking
Second-time buyers extending or refurbing family homes, and long-time owners finally replacing 90s installs that are now on their second failure.
In Caerphilly specifically that reads as young families upgrading first homes, long-time owners replacing original 90s uPVC. The recurring driver for a uPVC windows enquiry is: Homeowners looking to fix the bay-window mismatch and warm the property up as one job.
Local context — Caerphilly
- Council
- Caerphilly
- Postcodes
- CF83
- Main route
- A468
- Nearest town
- Cardiff (7 mi)
Neighbourhoods we cover: Bedwas, Trethomas, Machen, Energlyn, Llanbradach. Easy in via the A469, and we're 10 minutes from the A470 for vans loaded with full-house glass.
Our uPVC windows spec for a 1930s semi-detached
The whole-property refresh usually means a two-storey bay upgrade with reinforced corner posts and a matched foil across every remaining opening. Anthracite is the majority-buyer choice on 30s stock. In Caerphilly we see this on the stone-fronted terraces, post-war semis around the castle and newer estates out toward Bedwas around Bedwas, Trethomas, Machen, usually paired with wind-driven rain off the mountain ridge; noise from the A469 corridor; tired 1990s-era double glazing failing at the seals on the same elevation. Easy in via the A469, and we're 10 minutes from the A470 for vans loaded with full-house glass. Council area is Caerphilly County Borough Council in Mid Glamorgan; commercial neighbours include Pontygwindy Industrial Estate and Bedwas House Industrial Estate. Nearby: Cardiff 7mi, Newport 11mi, Pontypridd 10mi. Local vibe: market town with the castle as the centrepiece — a mix of stone period stock and modern estates.
Common 1930s semis problems we quote uPVC windows for
- 1Porch canopy timber has rotted at the fixings.
- 2Back kitchen extension has 90s uPVC with fogged units and dropped hinges.
- 3Original steel-frame Crittall casements replaced piecemeal, so no two windows match.
What we typically find on survey
- ·The porch-roof lead flashing has been dropping water onto the head of the front door for years.
- ·The frame reinforcement steel inside the outer frame has begun to rust and stain the internal white finish.
- ·The garden gate side of the property gets no direct sun and the frames there look ten years newer than the fronts.
- ·The transom bar has a live crack in the plastic, opened up by summer expansion cycles.
- ·The internal window board has swelled at the sink end from years of splash and is delaminating along the front edge.
- ·The composite door slab has a hairline crack along the letterplate cut-out from a delivery boot.
- ·There is a paint bridge from the internal architrave to the frame that will crack the moment the new unit lifts out.
- ·The internal reveal plaster is spalling under the cill where condensation has run for years.
- ·The window boards inside are chipboard, swollen at the edges from years of trickle condensation.
- ·The bottom rail on the sash has taken years of rain runoff and swollen enough to bind on the frame.
- ·The frame drainage slots at the bottom are clogged with debris, so rainwater sits inside the chamber.
- ·Every casement in the property opens with a firm tug on the second click — the friction stays are seized.
- ·A weep vent that was factory-drilled has been over-painted three times and no longer clears water from the chamber.
- ·The composite slab has swelled by 2mm on the hinge stile from years of morning-sun exposure.
- ·The letterbox opening is not draught-proofed at all — a candle held two feet away flickers in a light wind.
- ·A homemade timber threshold has been screwed to the concrete cill in front of the patio door.
- ·The bottom track on the sliding door has a build-up of grit that the rollers grind through every open cycle.
- ·The old timber back door has a live rot pocket at the bottom hinge that reads soft to a screwdriver tip.
- ·The friction hinge on one window sticks at 45° open and needs the palm of a hand to nudge past.
- ·The mid-rail on the composite door is bowed outward at the middle by 2mm — a slab-warp symptom.
- ·The multipoint lock still throws but the internal handle has 40° of dead travel before engaging.
- ·The manufacturer's kite mark on the corner of the glass is late-90s vintage, which explains the thermal performance.
- ·The front door threshold weather-bar seal is missing its rubber blade and the metal channel is bent.
- ·A previous fitter foam-filled the reveal gap directly against the frame, and the foam has now pushed the jamb inward.
Why residents are enquiring right now
- ·The homeowner is targeting a specific EPC band ahead of a rental switch and needs the frames to contribute measurably.
- ·The buyer wants a written commitment on the sealant colour and the trim colour before any deposit changes hands.
- ·The owner is done with rattling frames in a westerly and wants a demonstrable acoustic upgrade, not a numerical claim.
- ·The buyer is done with the sound of the frames rattling in a gale.
- ·The owner has tried draught-excluder tape and a chimney balloon and now accepts the frames themselves are the cause.
- ·The homeowner has quotes from two national companies and wants a local one to be honest about the same job.
- ·The homeowner is planning a loft conversion next year and wants the windows sorted before scaffold cost is priced.
- ·The buyer is buying the property specifically for the garden and wants a bi-fold that opens the whole rear elevation.
- ·The resident wants the sliding door to open with a fingertip after ten years of use, not two hands after two.
- ·The buyer wants the sound of the sea audible but the wind noise gone.
- ·The homeowner is on a smart meter and can see the room-by-room heat loss on a phone app.
- ·The owner is dealing with a partner who works nights and needs the bedroom acoustically watertight before summer.
- ·The homeowner wants the property EPC to move up a band ahead of a remortgage in six months.
- ·The homeowner is selling the property and only wants to replace what visibly holds the survey back.
- ·The resident wants the kitchen brighter in the mornings without losing the privacy from next door's back garden.
- ·The resident cycles to work and wants a bike-in-porch design that a survey needs to plan around.
- ·The owner is buying and wants to time the frame swap for the week between exchange and moving in.
- ·The buyer wants a specific coloured composite front door because they saw it three doors down and it made the street.
- ·The homeowner is preparing the property for a smart-home installation and wants sensor pockets designed into the reveals.
- ·The buyer wants a genuine Which? Trusted Trader install, not a subcontracted crew running the badge.
- ·The homeowner is selling within eighteen months and wants the front elevation to photograph well for the listing.
- ·The owner is done reheating rooms every hour because the frames leak the heat straight back out again.
- ·The buyer is moving in with two dogs and needs a back door that will not degrade with claw scrape.
- ·The resident wants the crew to be locals who won't disappear if a warranty call needs answering in year eight.
How we actually fit it
- ·The frame reinforcement is chosen for the wind load exposure of the elevation, not the smallest steel that fits.
- ·We de-glaze into a padded rack, not straight into the skip — the intact panes go to a glazier for reuse.
- ·The lead fitter leaves a handwritten note of anything the client should watch in the first month, not a printed generic checklist.
- ·Cavity closers get inserted where the old frame's cavity closer has failed — not omitted because it is unseen work.
- ·The multipoint gearbox is thrown by hand before the frame goes in — a factory fault at that point is a five-minute fix.
- ·The multipoint keeps get a smear of grease inside the pocket before the door is closed for the first time.
- ·The perimeter tape between frame and reveal is a compressible foam tape, not a plain butyl strip.
- ·The frame is protected with a low-tack film across any face a tool might touch during the fitting hour.
- ·The crew asks the client where the kettle lives before they set up so tea gets made rather than negotiated.
- ·The composite slab is not trimmed on site — if it doesn't fit, a new slab is ordered rather than reduced.
- ·The frame is plumbed on two axes before the first fixing goes in — not one axis and then trusted.
- ·The frame drainage caps face outward and are set proud enough that they don't clog with a season of rainwater.
- ·The crew takes the old glass off site in a labelled sack that day, not a skip left on the drive.
- ·The old broken glass is bagged in a labelled sack, not tipped loose into a general skip.
- ·The composite slab is not cut on site — if it does not fit, a new slab is ordered rather than trimmed.
- ·The head of the frame is packed dry before the sides are fixed, so the frame does not distort during installation.
- ·The dustsheet inside the room is a heavy canvas taped to the skirting, not a light plastic left loose.
- ·The reveals are photographed on arrival so any pre-existing damage is on record before the crew touches them.
- ·The bead-in tools are rubber-faced, not steel — a steel tool marks the profile within minutes.
- ·The old keys are collected and destroyed, not left in a bag on the drive.
- ·The old debris leaves in a single tidy load — not skip visits three days apart.
- ·The door is closed, locked, and left overnight before final adjustment, so any settlement is captured before sign-off.
- ·The crew photographs the finished elevation from the street and shares it with the office as the sign-off record.
- ·The letterplate cowl is checked to swing free without touching the door face — a rubbing cowl marks the paint within weeks.
Free uPVC windows survey — 1930s semi-detached, Caerphilly
Book a 30-minute visit. We walk every reveal, sample the white, anthracite grey, black, foiled woodgrains against the elevation, and email a written figure inside 24 hours.
Summary — uPVC windows on a 1930s semi-detached in Caerphilly
We fit uPVC windows on 1930s semis across single window in 90 minutes, full-house in 1–3 days, using A+ rated multi-chamber uPVC with white, anthracite grey, black, foiled woodgrains. Hardware fails on schedule at year 8–10; upgrading hinges alone during a full re-glaze extends the frame life a decade. Original oak lintels can be scored and treated, not replaced, when they sit sound above a new frame. Written figure inside a day of the survey. Rear outshut kitchens often have flat felt roofs at 2.1m — glass and frame heights are set to clear the eaves. Tile porches are laid on a lime bed that reacts poorly to modern silicone; we mask and use low-modulus polymer instead. Salt spray in high winds reaches inland elevations at coastal properties — we spec stainless furniture on rear frames too. Original patio door tracks sit direct on the floor slab — we lift, level and re-set on stainless packers.
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