We use essential cookies to run this site, and optional cookies only with your consent. Cookie policy AcceptReject Open 7 days · Hours vary by day · 25 years' experience Office: 01279 216 215 | Mobile: 07932 442502 Services Areas About Our Work Blog Reviews Contact 01279 216 215 Free Quote - Home - Building & Construction - Loft Conversions Loft Conversions # Loft Conversions in Bishop's Stortford & Hertfordshire Velux, dormer and hip-to-gable loft conversions — adding bedrooms, bathrooms and home offices to your existing property without losing the garden. Get a Free Quote 01279 216 215 25 years' experience Five-star rated Workmanship guarantee 25 Years' Experience Workmanship Guarantee SafeContractor Approved Gas Safe (where required) Open 7 Days Herts & Essex Coverage Overview ## More Space Without Losing the Garden A loft conversion adds usable square footage to a property without taking a single square metre from the garden — and typically returns 15–25% to property value. For growing families and homeworkers across Hertfordshire, it's one of the highest-value projects you can commission. We deliver three core conversion types: Velux conversions (using existing roof space with new rooflights), dormer conversions (adding a box dormer to gain headroom and floor area), and hip-to-gable conversions (squaring off a hipped end to dramatically increase usable space). The right choice depends on your roof shape, your headroom, and your budget — we'll talk through all three on the first visit. Why It Matters ## Why Cheap Loft Conversions End Up Costing More Loft conversions live or die on three structural details: the floor (existing ceiling joists are almost never strong enough — proper engineered floor joists are needed), the staircase (must meet Part K of the Building Regs and not eat half the room below), and the head height (1.9m minimum at the head of the stairs is non-negotiable for Building Regs sign-off). Cheap conversions skimp on one or all three. The result is a "useable" space that sags, an unsigned-off conversion that creates problems on resale, or a staircase position that destroys the room beneath. We design to Building Regs from the first sketch — never bolt them on later. Our Process ## How We Deliver Loft Conversions 01 ### Feasibility Survey We measure existing head height, assess roof structure, and confirm what conversion type your property can actually take. 02 ### Site Measure & Quote Detailed site measure, scope agreed in writing, fixed itemised quote covering everything we'll do. 03 ### Programme & Materials Build programme agreed, materials specified and ordered, lead-in dates locked in before we start on site. 04 ### Build 8–12 weeks of fully managed build — joists, dormer (if applicable), insulation, plasterboard, staircase, plumbing, electrics, finishes. 05 ### Handover & Guarantee Building Control sign-off, snagging, written guarantee, and a fully usable new room. Benefits ## What You Get with J&Co ### Adds 15–25% to Value Typical Hertfordshire return on a well-executed loft conversion. ### Building Regs Compliant Designed to Part K, B and L from day one — full Building Control sign-off. ### All Trades Coordinated Carpenters, roofers, plasterers, electricians, plumbers managed in-house. ### Workmanship Guarantee Workmanship cover on every loft conversion — terms confirmed on your quote. Technical Detail ## Velux vs Dormer vs Hip-to-Gable — Which One? Velux (rooflight) conversions are the cheapest and least intrusive. The existing roof structure stays as-is and Velux rooflights are added to bring in light. Works only if you already have sufficient head height — typically only suited to traditional cut-roof houses with steep pitches. Ideal for converting an existing usable loft into a properly habitable room. Dormer conversions are the most common. A box dormer is added to the rear of the roof, dramatically increasing head height and usable floor area within the new space. Usually allows a double bedroom plus en-suite within the converted space. Often achievable under permitted development rights, depending on cubic volume rules. Hip-to-gable conversions apply to semi-detached and detached houses with a hipped roof end. The hip is "squared off" to create a vertical gable wall, massively increasing the usable internal volume. Often combined with a dormer on the rear for the maximum possible space gain. Almost always needs full planning permission. Many of our clients combine a loft conversion with a rear extension to maximise both ground-floor and first-floor space in one programme — usually saves on scaffold and management costs. Velux loft conversion with skylights — bedroom configuration with en-suite. Honest Pricing ## How Much Does a Loft Conversion Cost in Hertfordshire? 2026 guide ranges below — every conversion quoted individually after a feasibility survey. Velux conversion £35,000–£55,000 Minimal structural change, new rooflights, new staircase, full insulation and finish. Dormer conversion £50,000–£75,000 Box dormer added, full new floor structure, staircase, en-suite typically included. Hip-to-gable + dormer £70,000–£110,000+ Maximum space gain, full planning required, structural reconfiguration. ### What affects the price - Conversion type (Velux / dormer / hip-to-gable) - Inclusion of en-suite - Staircase position and complexity - Existing roof structure (cut roof vs trussed) - Insulation and finish specification - Planning vs permitted development route Get Your Free Written Quote Service Area ## Areas We Cover for Loft Conversions We deliver this service across our full Hertfordshire and Essex catchment. Regular projects in Bishop's Stortford, Sawbridgeworth, Harlow, Saffron Walden, Stansted Mountfitchet, Great Dunmow, Epping, Ware, Hoddesdon, Broxbourne, Cheshunt, Welwyn Garden City and Stevenage. Outside this list? Call us with your postcode — we frequently work the wider London fringe and across the rest of Hertfordshire. Guides ## Loft Conversions guides & cost advice Free, no-nonsense reading from Jamie on the questions we get asked most about loft conversions. - Loft Conversion Cost UK 2026: Full Price Guide Loft conversions have a wide price range — anywhere from £30,000 for a basic Velux up to £90,000+ for a mansard. Here's what each type actually costs in 2026 and what drives the variation on real Hertfordshire jobs. - Dormer vs Velux Loft Conversion: Which Is Right for You? Velux is cheaper, faster and usually doesn't need planning. Dormer adds significantly more usable head height and floor area. Here's how to choose between the two on real budgets and real roofs. Recent Work ## Recent Loft Conversions Projects View full portfolio FAQs ## Loft Conversions — Frequently Asked Questions ### svg]:rotate-180 text-left font-bold text-base hover:no-underline py-5" data-radix-collection-item=""> How long does a loft conversion take? ### svg]:rotate-180 text-left font-bold text-base hover:no-underline py-5" data-radix-collection-item=""> Do I need planning permission? ### svg]:rotate-180 text-left font-bold text-base hover:no-underline py-5" data-radix-collection-item=""> Will I have enough headroom? ### svg]:rotate-180 text-left font-bold text-base hover:no-underline py-5" data-radix-collection-item=""> What about the staircase? ### svg]:rotate-180 text-left font-bold text-base hover:no-underline py-5" data-radix-collection-item=""> Can I get a bathroom in the loft? ### svg]:rotate-180 text-left font-bold text-base hover:no-underline py-5" data-radix-collection-item=""> Will my loft conversion add value? ### svg]:rotate-180 text-left font-bold text-base hover:no-underline py-5" data-radix-collection-item=""> Is the work guaranteed? Related Services Building & Extensions Renovations & Refurbishments Plastering & Rendering Roof Repairs & Maintenance Back to Building & Construction ## Get a Free Loft Conversion Quote Feasibility survey, fixed itemised quote, fully managed build. Across Hertfordshire and Essex. Request Free Quote 01279 216 215 Page last updated: May 2026 · J&Co Builders Ltd · 1 Ugley Hall Cottages, Bishop's Stortford CM22 6JB Owner-led roofing and building contractors covering Bishop's Stortford, Hertfordshire and Essex. 25 years of hands-on trade experience. Open seven days. 01279 216 215 (office) 07932 442502 (mobile) info@jandco-contractorsltd.co.uk 1 Ugley Hall Cottages, Bishop's Stortford CM22 6JB Open 7 days a week - Sun 07:00–17:30 - Mon 07:00–17:00 - Tue 07:30–17:00 - Wed 07:00–17:30 - Thu 07:00–17:30 - Fri 06:00–18:00 - Sat 09:00–17:00 We accept VISAAMEX PayG Pay ### Roofing - All roofing services - Flat Roofing - Roof Repairs & Maintenance - Emergency Roof Repairs - Guttering, Fascias & Soffits - Chimney Repairs & Repointing ### Building & Construction - All building services - Building & Extensions - Loft Conversions - Renovations & Refurbishments - Brickwork & Masonry - Damp Proofing & Waterproofing - Plastering & Rendering - Patio & Driveway Installations - Fencing & Garden Walls - Property Maintenance ### Areas We Cover - Bishop's Stortford - Stansted Mountfitchet - Sawbridgeworth - Great Dunmow - Harlow - Saffron Walden - Epping - Ware - Hoddesdon - Broxbourne - Cheshunt - Welwyn Garden City - Stevenage ### Company - About J&Co - Our Recent Work - Blog - Customer Reviews - Contact Us © 2026 J&Co Builders Ltd · Trading as J&Co Contractors · All rights reserved. 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