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 - Damp Proofing & Waterproofing Damp Proofing & Waterproofing # Damp Proofing & Waterproofing in Bishop's Stortford & Hertfordshire Rising damp, penetrating damp and basement tanking — diagnosed properly first, treated proportionately. Most damp problems are misdiagnosed and over-treated. We don't do that. 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 ## Damp Diagnosis Done Honestly The UK damp proofing industry has a credibility problem — too many surveyors selling chemical injection treatments for problems that don't actually need them. The reality is that the majority of "rising damp" cases are actually penetrating damp, condensation, or bridged DPCs caused by raised external ground levels. We diagnose first using moisture readings, salt analysis and visual inspection — not by walking in with a chemical injection quote already drafted. Where chemical injection is genuinely needed, we install it properly with full re-plaster of the salt-damaged plaster. Where it isn't, we'll tell you what the actual problem is and quote the proportionate fix. Why It Matters ## Why Damp Misdiagnosis Costs You Thousands The classic mistake: damp patch on the wall, "damp surveyor" called, chemical injection DPC quoted, plaster stripped and replaced — six months later the damp is back, because the actual cause was a leaking external gutter, a bridged cavity, or a raised driveway pushing rainwater above the original DPC. The chemical injection was treating a symptom that wasn't the actual problem. Done properly, damp diagnosis includes external inspection of gutters, ground levels, render condition, pointing and any abutting structures (extensions, conservatories) before any internal "treatment" is quoted. Skip this and you'll often pay for chemical injection that does nothing for the actual cause. Our Process ## How We Deliver Damp Proofing & Waterproofing 01 ### Full Damp Survey External and internal inspection, moisture readings, salt analysis where relevant, photographic evidence. 02 ### Honest Diagnosis Report Written diagnosis explaining what the actual cause is — often surprisingly different from the obvious assumption. 03 ### Itemised Quote Proportionate treatment quote — could be chemical DPC, could be external repair, could be ventilation. We quote what's actually needed. 04 ### Treatment Works Whether it's DPC injection, render removal and replacement, external repair, or basement tanking — done to BS 8102 standards. 05 ### Guarantee Workmanship guarantee on all damp works — exact terms confirmed in writing on the quote, with manufacturer-backed cover passed on where the product carries it. Benefits ## What You Get with J&Co ### Diagnose First External and internal inspection before any treatment is quoted. ### Proportionate Treatment We quote what's needed — not the most profitable option. ### BS 8102 Compliance Basement tanking and waterproofing to British Standard 8102 specifications. ### Workmanship Guarantee Written guarantee on every damp job — terms confirmed on your quote, plus any product manufacturer cover passed on. Technical Detail ## Rising vs Penetrating vs Condensation — Three Different Problems Rising damp is moisture rising from ground level through brickwork by capillary action. Genuine rising damp is rare — it requires the absence or failure of a damp proof course AND ground-level moisture. Identified by tide marks at consistent height around external walls, salt deposits at the tide mark, and damp readings that decrease with height up the wall. Penetrating damp is moisture entering walls externally — usually through failed pointing, cracked render, blocked gutters, raised ground levels bridging the DPC, or defective flashings. Identified by damp patches that don't follow consistent tide marks and that vary with weather conditions. Treatment is usually external repair, not chemical injection. Condensation is by far the most common diagnosis we make — moisture from cooking, washing and breathing condensing on cold internal surfaces. Identified by black mould growth, particularly in corners and behind furniture against external walls. Treatment is improved ventilation (extract fans, PIV systems) and insulation, not chemical injection. Many damp problems coincide with roof or roofline issues — see our roof repair service and guttering, fascia and soffit service for related work that often resolves "damp" problems for a fraction of the cost. Chemical DPC injection followed by full salt-resistant re-plaster — the correct full treatment. Honest Pricing ## How Much Does Damp Proofing Cost in Hertfordshire? Honest guide ranges below — diagnosis-first survey usually quoted separately and credited against treatment if you proceed. Damp survey £200–£450 Full external + internal inspection with written diagnosis report. Credited against treatment cost if you proceed. Chemical DPC + re-plaster £1,200–£3,500 Per affected wall — including injection, salt-resistant re-plaster and finishing. Basement tanking £3,500–£15,000+ Cementitious tanking or cavity drainage system to BS 8102. Quoted by area and complexity. ### What affects the price - Type of damp (rising, penetrating, condensation) - Number of walls affected - Re-plaster requirement - External works needed (pointing, render) - Basement / below-ground area (if applicable) - Required guarantee period Get Your Free Written Quote Cost Factors ## What Affects the Cost of Damp Proofing? Damp is only quoted after diagnosis, because the cause dictates the treatment. These are the factors that shape the price. ### Type of damp Rising, penetrating and condensation are three different problems with three different fixes. Treating the wrong one costs money and solves nothing. ### Method required Chemical DPC injection, cementitious tanking or cavity drainage, external repair, or ventilation improvements — each carries a very different labour and material cost. ### Size of the affected area A single internal wall is a contained job. Whole-ground-floor or full-basement work involves far more preparation, treatment and re-plastering. ### Whether re-plastering is needed Salt-contaminated plaster has to come off and be replaced with a specified render and plaster system, plus drying time before decoration. ### Whether a survey is needed first Anything beyond an obvious external defect needs a proper damp survey with moisture readings so the treatment is based on evidence, not guesswork. Get a Free Quote Service Area ## Areas We Cover for Damp Proofing & Waterproofing 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. FAQs ## Damp Proofing & Waterproofing — Frequently Asked Questions ### svg]:rotate-180 text-left font-bold text-base hover:no-underline py-5" data-radix-collection-item=""> Is rising damp real? ### svg]:rotate-180 text-left font-bold text-base hover:no-underline py-5" data-radix-collection-item=""> Do I always need chemical DPC injection? ### svg]:rotate-180 text-left font-bold text-base hover:no-underline py-5" data-radix-collection-item=""> How do I know if I have a damp problem? ### svg]:rotate-180 text-left font-bold text-base hover:no-underline py-5" data-radix-collection-item=""> How long do damp proofing guarantees last? ### svg]:rotate-180 text-left font-bold text-base hover:no-underline py-5" data-radix-collection-item=""> Will damp proofing affect my home insurance? ### svg]:rotate-180 text-left font-bold text-base hover:no-underline py-5" data-radix-collection-item=""> Can you do basement tanking? ### svg]:rotate-180 text-left font-bold text-base hover:no-underline py-5" data-radix-collection-item=""> How long does damp work take? ### svg]:rotate-180 text-left font-bold text-base hover:no-underline py-5" data-radix-collection-item=""> How much does damp proofing cost? ### svg]:rotate-180 text-left font-bold text-base hover:no-underline py-5" data-radix-collection-item=""> What are the signs of rising damp? ### svg]:rotate-180 text-left font-bold text-base hover:no-underline py-5" data-radix-collection-item=""> How long does a damp proofing treatment last? ### svg]:rotate-180 text-left font-bold text-base hover:no-underline py-5" data-radix-collection-item=""> Do I need a survey before treatment? ### svg]:rotate-180 text-left font-bold text-base hover:no-underline py-5" data-radix-collection-item=""> Can damp come back after treatment? Related Services Plastering & Rendering Brickwork & Masonry Renovations & Refurbishments Roof Repairs & Maintenance Back to Building & Construction ## Get an Honest Damp Diagnosis Diagnose first, treat proportionately, guarantee properly. 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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