Monday – Friday: 9:00am – 4:30pm 029 2002 3280
Windows, Doors &
Conservatories in
South Wales
Family-run. FENSA registered.
Over 30 years of local experience.
What Can We Do For You?
Windows
Stylish, energy-efficient windows for every home. Casement, sash, flush, tilt & turn — all A-rated and FENSA certified.
Explore WindowsDoors
Secure, beautiful doors that make a statement. Composite, bi-fold, patio and residential doors for every style of home.
Explore DoorsConservatories
Warm, comfortable spaces you can use all year round. LEKA warm roofs, orangeries, and bespoke designs for South Wales homes.
Explore ConservatoriesWindows, Doors & Conservatories Across South Wales
Daimant fits windows, doors and warm-roof conservatories across Caerphilly, Cardiff and South Wales, and yes, we are the company some people search for as diamond windows or diamant doors. We are one family-run firm, spelt Daimant, based at our Caerphilly showroom with over 30 years fitting quality glazing across the region.
If you want new windows, a secure front or garden doors, or a conservatories room you can use all year, you are in the right place. Pick the hub that fits your project below, or book a free home survey and we will measure up and price it in writing with no obligation.
- Daimant is a family-run, FENSA-registered installer based in Caerphilly, trading over 30 years.
- We fit windows, doors and warm-roof conservatories across Cardiff, Newport, the Vale and the Valleys.
- The name is Daimant, the same firm people sometimes search as diamond windows or diamant doors.
- Our LEKA warm roof makes a conservatory usable every day of the year, not just in summer.
- Deposits are protected through IWA insurance-backed guarantees.
- Every quote is free, in writing and pressure-free.
Looking for Diamond Windows
or Diamant Doors?
You’ve found us.
Daimant is our company name. It’s pronounced like ‘diamond’, which is why people sometimes search for us as Diamond Windows or Diamant Doors. Same company. Same team.
Get a fixed price for your project
Book a free home survey and we will measure, advise and leave you with a written quote, with no obligation.
Book a Free SurveyWho are Daimant?
We are a family-run installer of windows, doors and conservatories based in Caerphilly, trading for over 30 years. Everything we fit is installed by our own experienced teams rather than passed to subcontractors, which is how we keep the quality and the aftercare consistent from the first survey to the final sign-off.
You can read the full story on our about us page, but the short version is simple: local people, local fitters, and a showroom you can visit in Caerphilly to see the products before you buy. We are FENSA registered, so the glazing we install is certified against building regulations.
The name has a story that trips up the search engines. Daimant is pronounced like diamond, and over the years customers have found us under diamond windows and diamant doors as well. It is all the same business, run by the same family, working out of the same Caerphilly base since well before uPVC became the norm. That continuity is the point: the person who quotes your job is part of the firm that fits it and stands behind it afterwards.
Read our story
Diamond Windows
or Diamant Doors?
You’ve found us.
Are Daimant and diamond windows the same company?
Yes. The name is Daimant, pronounced like diamond, and searches for diamond windows or diamant doors usually mean us. There is one firm behind those spellings, based in Caerphilly and covering Cardiff and South Wales, so if a neighbour recommended any of those names, you have found the right place.
We mention this because brand confusion should never cost you a good installer. However you spell it in the search bar, the team, the showroom and the guarantees are the same.
What do you fit?
Three things, all done properly. New energy-efficient windows in casement, flush sash, sliding sash and tilt and turn styles. Doors from secure composite front doors to bifolds and patio doors for the garden. And warm-roof conservatories and orangeries that stay comfortable all year.
Start with the hub that matches your project. Our windows range covers everything from A-rated casements to heritage flush sash. Our doors hub runs from PAS 24 composite doors to wide bifolds. And our conservatories section explains the warm roof that makes the real difference.
Windows
Within windows, the choice usually comes down to the look you want and the age of the house. Casement windows are the everyday A-rated workhorse for most homes. Flush sash gives a timber look that conservation officers accept, sliding sash suits period frontages, and tilt and turn is the safe, easy-clean option for flats and upstairs rooms.
- Casement windows
- Flush sash
- Vertical sliding sash
- Tilt and turn
Doors
On doors, a composite front door leads on security and warmth, bifolds fold the back of the house open to the garden, and patio or French doors do the same where space or budget is tighter.
- Composite front doors
- Bifolds
- Patio and French doors
Conservatories
And our conservatories section explains the warm roof that makes the real difference.
- New warm-roof builds
- Orangeries
- Roof replacements
Energy efficiency
across the range
Every window we fit is A-rated as standard, with a warm-edge spacer bar, argon fill and a low-emissivity coating, bringing U-values down to around 1.2 W/m²K against roughly 3.1 for tired 1990s double glazing and near 5.0 for old single glazing. That gap shows up on the EPC and on the heating bill. Doors and conservatory glazing use the same specification, so the whole house works together rather than leaking heat through the weakest element.
Better Glazing.
Less Heat Lost.
Do you cover my area?
We fit right across the region from our Caerphilly base. That includes the whole of Greater Cardiff, from Cyncoed and Llanishen to Whitchurch and Pontcanna, the Vale towns of Penarth and Barry, Newport and Gwent, and the Valleys communities of Ystrad Mynach, Bargoed and Pontypridd.
If you are in Cardiff or nearer home in Caerphilly, we can usually survey within a week or so. Not sure if you are in range? Ask us and we will tell you straight away.
Our Caerphilly base sits close enough to Cardiff to reach the city suburbs quickly, and we know the housing there well, the bay-fronted semis of Cyncoed and Rhiwbina, the terraces of Cathays and Pontcanna, the newer estates towards Whitchurch. North of us the Valleys towns of Bargoed, Ystrad Mynach and Pontypridd are core territory, and we head south to Penarth and Barry in the Vale and east to Newport and Gwent. Wherever you are in that patch, one team surveys, quotes and fits.
Why choose a
local Caerphilly firm?
A local installer answers the phone, turns up to the survey and comes back if anything needs attention, because the business depends on its reputation across a small area. National sales operations rarely offer that. Our fitters know the housing stock here, from Valleys terraces to Cardiff semis, and specify accordingly.
Being local also keeps things honest on price. We give a fixed written quote after the survey, not a headline figure that only holds if you sign on the night. That is the difference between a firm that lives here and a sales team passing through.
There is a practical side too. When your fitters live locally, aftercare is a short drive rather than a call centre ticket, and if a hinge needs adjusting a year on, we come back. A firm rooted in one area cannot afford unhappy customers in the next street, so the incentive to get it right is built into where we work.
See The Difference
New Windows
Warm Roof
Vale of Glamorgan • South Wales Valleys
What makes your
conservatories different?
The roof. Most conservatories fail their owners because a glass or polycarbonate roof bakes the room in summer and loses heat in winter, so it goes unused half the year. We fit the LEKA warm roof, a lightweight insulated solid roof with a plastered ceiling, reaching roof U-values around 0.15 W/m²K.
Most conservatories fail their owners because a glass or polycarbonate roof bakes the room in summer and loses heat in winter, so it goes unused half the year.
That single change turns a seasonal glass box into a room you use every day. We can build new or replace the roof on an existing conservatory, often in just a few days.
We can fit the warm roof to a new build or retrofit it to an existing conservatory whose base and frames are sound, often in a few days, which is one of the most common jobs we do across Cardiff and the Valleys.
It is worth stressing because a conservatory is a big spend, and the difference between a glass roof and a warm roof decides whether you use the room or resent it. We can fit the warm roof to a new build or retrofit it to an existing conservatory whose base and frames are sound, often in a few days, which is one of the most common jobs we do across Cardiff and the Valleys.
How do I get a quote?
Book a free home survey and we do the rest. We measure up, talk through your options and finishes, and leave you with a fixed written quote. There is no charge, no deposit to see a price, and no obligation to go ahead.
You can book online through our book a free survey page. Tell us roughly what you have in mind and whereabouts you are, and we will arrange a visit that suits you.
On the survey itself, we measure accurately, check the existing openings and any structural points, and talk through styles, colours, glass and security options with you. You are not signing anything on the visit. A day or two later you get a fixed written quote you can compare at your leisure, and if you want to see and feel the products first, the Caerphilly showroom is open for you to visit.
Larger projects like a full house of windows or a conservatory can be spread with finance rather than paid in one go, and we will set out the options plainly if that helps. Deposits are protected through the IWA scheme either way, so paying over time does not weaken the guarantee behind the work.
Which areas around Caerphilly and Cardiff do we cover?
We work outwards from our Caerphilly base, so most of Greater Cardiff sits comfortably inside our fitting radius. That covers Cardiff suburbs such as Cyncoed, Llanishen, Whitchurch, Rhiwbina and Pontcanna, the Caerphilly county towns of Bargoed, Ystrad Mynach, Nelson and Bedwas, and out towards Newport, Caerleon and Rogerstone. If you are further along the Valleys in Pontypridd, Llantrisant or the Rhondda, or south in Penarth, Barry and the Vale, we still fit there regularly.
Being local is not a marketing line for us. It means the surveyor who measures your job and the fitters who install it are the same team, working from one Caerphilly workshop, and you can visit the showroom before you commit to anything. It also means aftercare is a short drive, not a call centre. If you want to see the standard of finish first, the gallery shows real installs on real South Wales streets.
- Cyncoed
- Llanishen
- Whitchurch
- Rhiwbina
- Pontcanna
- Bargoed
- Ystrad Mynach
- Nelson
- Bedwas
- Pontypridd
- Llantrisant
- Rhondda
- Newport
- Caerleon
- Rogerstone
- Penarth
- Barry
Worked Examples
Replacing every window on a Llanishen semi
A homeowner in Llanishen had draughty 1990s double glazing with misted units and rising heating bills. We surveyed, then quoted A-rated casement windows with warm-edge spacers and argon fill, moving the glazing from a tired U-value near 3.1 W/m²K down to around 1.2.
The job was fitted by our own team in two days, FENSA certified, and the couple noticed the difference on the first cold evening. As a guide, a full house of A-rated casements runs from around 4,000 to 7,000 pounds fitted depending on size and number of windows.
A warm-roof conservatory in Caerphilly
A family near Caerphilly wanted to use their conservatory in winter for once. The base and frames were sound, so rather than rebuild we fitted a LEKA warm roof with a plastered, spotlit ceiling in three days.
With a roof U-value near 0.15 W/m²K, the room now holds heat like the rest of the house and serves as a year-round family space. A roof replacement of that size sits from around 5,000 to 8,000 pounds fitted as a guide.
Frequently asked questions
Common questions about Daimant, our products, coverage and how to get a quote.
Let’s get your project priced
Book a free home survey with our Caerphilly team and get a fixed written quote for your windows, doors or conservatory, with no obligation.
