Pontypridd, South Walesinfo@lewzpropertydevelopment.co.uk Mon–Sat 7:00 – 18:00Company No. 15585929 About Services Service Areas Our Work Reviews Contact 07576 546805Request Estimate - Home - Services - Extensions & New Builds Extensions & New Builds · Pontypridd & South Wales # Extensions & New Builds.Foundation To Final Coat.One Team, One Quote. Single-storey, two-storey, wrap-around extensions and ground-up new builds across Pontypridd, Cardiff and the South Wales valleys — fully programmed, fully insured, fixed price in writing. Request Free Estimate 07576 546805 30+ Years Combined Trade Experience · Fixed Written Quotes · Same-Week Surveys Ground-up new builds Single & two-storey extensions Building control coordinated Fixed written quote Service Overview ## Extensions & New Builds —The Brief, In Plain English. ### What It Is An extension adds usable, planning-compliant space to your existing home — kitchen-diner, additional bedroom, garden room, loft or two-storey side return. A new build is a fresh ground-up house — foundations, shell, roof, services, finishes — built to current building regs. ### Who It's For Homeowners outgrowing their current footprint; families wanting open-plan living instead of moving; self-builders with a plot and architect drawings ready to break ground; landlords building HMOs or new rental units. ### When You Need It Once planning permission is approved (where needed) or your permitted development scope is confirmed, and structural drawings are in hand. Spring and summer starts give the best weather window for the watertight stage. ### Why It Matters Extensions and new builds fail at the joins between trades. Steel sat on the wrong padstone. Cavity tray missed at the abutment. Insulation cold-bridged at the eaves. A single team that owns groundworks through to plaster removes the gaps where problems hide. What Happens If You Wait ## The Cost OfDoing Nothing. Half-managed extensions are where money disappears. The bits no surveyor checks at the end are the bits that fail. ### Risks Of Ignoring It - →Cold bridging at junctions — condensation, mould, EPC tanked. - →Missed cavity trays and DPC — damp at first-floor level a year in. - →Steel under-bearing or wrong padstone — cracks above doors. - →Roof tie-in detail botched — water tracking back into the original house. - →Building control sign-off refused — house unsellable until rectified. ### Common Mistakes Customers Make - ×Letting an architect manage the build (different skill). - ×Picking the cheapest groundworks quote. - ×Ordering the kitchen before the structure is plastered out. - ×Not budgeting for finishes — the last 20% always feels like 40%. Our Process ## First Call ToFinal Sign-Off. 01 ### Plans & Survey We review architect drawings and structural calcs on site, raise any buildability issues, agree spec before quoting. 02 ### Fixed Quote & Programme Itemised written quote and dated programme — dig, pour, shell, roof, services, plaster, finishes — building control schedule mapped in. 03 ### Groundworks & Shell Dig, foundations, oversite, drainage, blockwork to DPC, brickwork shell, steel install, roof construction to watertight. 04 ### First & Second Fix First-fix electrics and plumbing, insulation, plasterboard, plaster, screed. Then second-fix electrics, plumbing, joinery, kitchen, bathroom, decoration. 05 ### Sign-Off Final building control inspection, snag walk-around, certificates and paperwork pack handed over. Why It's Worth It ## What YouActually Get. ### Single-Team Accountability One programme, one phone number, one written quote — no finger-pointing between subcontractors when things go wrong. ### Buildability Reviewed Up Front We check the architect's drawings against reality on day one — better to redraw on paper than rebuild in brick. ### Detailing Done Properly Cavity trays, DPC, weep vents, fire stopping, insulation continuity — the boring details that pass building control first time. ### Programme On The Wall Dated milestones agreed before we lift a tool — you know what's happening each week. ### Future-Sale Ready Full paper trail — structural calcs, building control certs, electrical and gas certificates. Material the buyer's surveyor will ask for. In Detail ## Extensions & New Builds —Every Variation Covered. Materials, methods and the situations each variation applies to — so you know what you're buying before you buy it. Working across Pontypridd · Rhondda · Ynysybwl & Abercynon · Talbot Green · Aberdare · Merthyr Tydfil · Caerphilly Full Service Area Map ### Single-Storey Rear & Side Extensions Kitchen-diners, garden rooms, utility extensions — typically under permitted development. Steel goal-post or flush-fit beams, large sliding or bi-fold openings, flat or pitched roofs, MVHR and underfloor heating where wanted. Coordinated with the existing house drainage and electrics. ### Two-Storey & Wrap-Around Extensions Side returns, two-storey rear extensions, full wrap-arounds adding bedrooms above living space. Structural complexity steps up — pile foundations or engineered raft, party wall agreements, more steel — we manage the lot. ### Loft & Attic Conversions Dormer, hip-to-gable, mansard and rooflight conversions, structural ridge beam install, fire-regs-compliant stair, en-suite plumbing. See our Loft & Attic Conversions service for full detail. ### Ground-Up New Builds Single dwellings to small multi-unit developments — full groundworks, drainage, foundations, shell, roof, full services, fit-out and external works. Built to current Part L thermal performance, with the paperwork trail to prove it. ### Residential vs Commercial New Build Domestic projects run on facing brick, slate or tile, traditional detailing. Commercial / mixed-use shifts to blockwork inner skin, faster envelope systems and accelerated programmes — we work to either spec. Questions ## StraightAnswers. Cost, timeline, guarantees, lifespan, emergency availability — the questions everyone asks, answered before you call. Ask Yours ### How much does an extension cost in South Wales? +Roughly indicative ranges: a basic single-storey rear extension starts low five figures per m² fitted; a two-storey extension and full kitchens push that up sharply. We give itemised fixed quotes after reviewing your drawings on site. ### How long does a single-storey extension take? +Typically 10–16 weeks from groundbreak to handover for a standard rear extension, depending on size, foundation type and finishes. Two-storey extensions usually run 16–24 weeks. ### Do I need planning permission? +Many single-storey rear extensions fall under permitted development, but two-storey and side extensions usually need planning. We'll tell you on the first site visit which route applies and recommend a planning consultant if needed. ### Do you work from my architect's drawings? +Yes — bring your drawings and structural calcs. We'll review them on site and raise any buildability issues before pricing. ### Do you handle party wall matters? +We don't act as party wall surveyors, but we coordinate with your appointed surveyor and time the works around any agreed access conditions. ### What paperwork comes with a new build? +Manufacturer paperwork on installed kits, plus building control sign-off. For mortgageable new builds we can build to a structural warranty provider's standards on request. ### Can you build to Passivhaus or low-energy standards? +We work to current Part L as standard and can build to enhanced thermal performance specs — airtightness detailing, MVHR, continuous insulation — when designed in from drawings. ### Do you cover Cardiff and Bristol as well as Pontypridd? +Yes — Pontypridd, Aberdare, Cardiff, Caerphilly, Bridgend, Barry, Newport, Merthyr Tydfil and Bristol all sit within our regular working area. Next Step ## Got Drawings? Let's Price Your Build. Free site survey within our coverage area, written quote typically within 48 hours, no obligation. 30+ years' combined trade experience across the team, public liability insured, Pontypridd-based. Request Free Estimate 07576 546805 Public Liability Insured Company No. 15585929 30+ Years Combined Experience Related Services Bricklaying Whole-House Refurbishments End-to-End Builds Independent, owner-led local builders with 30+ years' combined trade experience across the team. Extensions, full renovations and ground-up builds across Pontypridd, Cardiff and the wider South Wales region. 07576 54680507581 312279info@lewzpropertydevelopment.co.ukPontypridd, South Wales ### EXPLORE - About - Services - Service Areas - Our Work - Reviews - Contact ### SERVICES - Bricklaying - Bathroom Renovations - Kitchen Renovations - Whole-House Refurbishments - Extensions & New Builds - Plastering ### SERVICE AREAS - Builders in Pontypridd - Builders in Rhondda - Builders in Ynysybwl & Abercynon - Builders in Talbot Green - Builders in Aberdare - Builders in Merthyr Tydfil - Builders in Caerphilly - Builders in Cardiff - Builders in Newport - Builders in Bridgend - Builders in Barry - Builders in Bristol © 2026 LEWZ Property Development Ltd. Company No. 15585929. All rights reserved. Privacy PolicyTerms & ConditionsCookie PolicyMon–Sat 7:00 – 18:00 Call NowGet Estimate