Damp Proof Course (DPC) Guide | Syla Damp Proofing ![Loading Syla Damp Proofing](https://syladamproofing.co.uk/img/logo/logo.svg) [ contact@syladamproofing.co.uk ](mailto:contact@syladamproofing.co.uk) Mon–Fri 8am–6pm · Sat 9am–2pm [Book a free damp survey](https://syladamproofing.co.uk/request-a-damp-survey) [ 07399 539 436](tel:07399539436) | [ 020 3051 3196](tel:02030513196) [ ![](https://syladamproofing.co.uk/img/icons/bar_icon.svg) ](javascript:void(0)) [![Syla Damp Proofing — back to homepage](https://syladamproofing.co.uk/img/logo/logo.svg)](https://syladamproofing.co.uk) - [Home](https://syladamproofing.co.uk) - [Our Services](https://syladamproofing.co.uk/services) - [Resources](https://syladamproofing.co.uk/blog) - [Our Work](https://syladamproofing.co.uk/gallery) - [About Us](https://syladamproofing.co.uk/about-us) - [Contact Us](https://syladamproofing.co.uk/contact-us) - [Get In Touch](https://syladamproofing.co.uk/contact-us) [![Syla Damp Proofing — back to homepage](https://syladamproofing.co.uk/img/logo/logo.svg)](https://syladamproofing.co.uk) - [](https://facebook.com) - [](https://instagram.com) - [ ](https://www.mybuilder.com/profile/syla_damproofing) [![Syla Damp Proofing — back to homepage](https://syladamproofing.co.uk/img/logo/logo.svg)](https://syladamproofing.co.uk) #### Office Address Flat 35, The View Staines Road West, Sunbury-on-Thames, TW16 7FF #### Phone & Mobile Number [020 3051 3196](tel:02030513196) [07399539436](tel:07399539436) #### Email Address [](https://www.facebook.com/syladamproofing) [ ](https://www.instagram.com/syla_damp_proofing_) [ ](https://www.mybuilder.com/profile/syla_damproofing) [ ](https://www.checkatrade.com/give-feedback/1097677?utm_source=members_area&utm_medium=link&utm_campaign=review_reminder&utm_content=ttr_id) ![Syla Damp Proofing](https://syladamproofing.co.uk/img/logo/logo.svg) Syla Damp Proofing +44 20 3051 3196 contact@syladamproofing.co.uk https://syladamproofing.co.uk ![Syla Damp Proofing](https://syladamproofing.co.uk/img/logo/logo.svg) Guide Damp Proof Course (DPC) Guide ============================= Understanding damp proof courses and when they need attention +44 20 3051 3196 4.9 (47 reviews) Damp Proof Course (DPC) Guide ============================= [Home](https://syladamproofing.co.uk) / Damp Proof Course (DPC) Guide ![Damp Proof Course (DPC) Guide image](https://syladamproofing.co.uk/img/services/services_img02.jpg) GuideUnderstanding damp proof courses and when they need attention ------------------------------------------------------------- A damp proof course (DPC) is a barrier built into the walls of a property to prevent moisture from the ground rising up through the masonry. Most properties built after the late 1800s include some form of DPC, but older London homes may have one that has failed, been bridged, or was never installed. When a DPC is missing or no longer working, rising damp can affect internal walls, damage plaster, and create conditions for mould and decay. This guide explains the main types of DPC, how failures occur, and what remedial options are available. Apparent DPC failure is often caused by bridging, not just by a failed barrier. The right remedial option depends on wall type, access, and the actual moisture path. Types of DPCHow damp proof courses are installed ------------------------------------ - Physical DPC: slate, bitumen felt, or engineering brick courses built into the wall - Chemical injection DPC: silicone-based or resin cream injected into a mortar course - Electro-osmotic systems: less common, using electrical charge to repel moisture - Modern remedial DPC: typically injection-based, the most common retrofit method Signs of DPC FailureWhen a damp proof course may not be working ------------------------------------------- Common signs include damp patches at or near skirting level, salt deposits on internal walls, peeling wallpaper, and a musty smell in ground-floor rooms. Bridging, where external ground levels, rendering, or paving sit above the DPC line, is one of the most frequent causes of apparent failure. Need help? **Request a proper survey before any treatment is specified.** Most relevant service **Rising and Penetrating Damp** [See Damp Treatment Service ![](https://syladamproofing.co.uk/img/icons/right_arrow.svg)](https://syladamproofing.co.uk/services/rising-and-penetrating-damp) Remedial OptionsWhat can be done about a failed or missing DPC ---------------------------------------------- ### Chemical injection The most widely used remedial method. A damp-proofing cream or fluid is injected into a drilled mortar course to create a new chemical barrier against rising moisture. ### Physical DPC insertion A new physical membrane is cut or inserted into the wall. Less common in remedial work but sometimes used on specific construction types where injection is not suitable. ### Addressing bridging In many cases, the existing DPC is intact but has been bridged by raised ground levels, render, or internal finishes. Removing the bridge can resolve the issue. Frequently Asked QuestionsCommon questions about this guide topic --------------------------------------- ### What is a damp proof course? A damp proof course (DPC) is a barrier built into a wall to prevent moisture rising from the ground into the masonry above. It can be a physical layer like slate or engineering brick, or a chemical injection. ### How do I know if my DPC has failed? Signs of a failed DPC include damp patches on internal walls at or below the DPC line, salt deposits, peeling decoration, and a musty smell at ground floor level. ### Can a damp proof course be repaired? A failed or missing DPC can often be remedied with a chemical injection DPC, which creates a new moisture barrier within the existing masonry. The approach depends on the wall type and construction. Related GuidesHelpful background before you book remedial work ------------------------------------------------ ### [Signs of Rising Damp](https://syladamproofing.co.uk/guides/signs-of-rising-damp) A practical guide to the common signs people notice before arranging an inspection for rising damp treatment. ### [What Causes Penetrating Damp?](https://syladamproofing.co.uk/guides/what-causes-penetrating-damp) An overview of why penetrating damp occurs, how it differs from rising damp, and what to look for in your property. ### [Rising Damp, Penetrating Damp, or Condensation?](https://syladamproofing.co.uk/guides/rising-damp-penetrating-damp-or-condensation) How to tell the difference between rising damp, penetrating damp, and condensation before choosing a treatment. ### [Damp Proofing Costs in London](https://syladamproofing.co.uk/guides/damp-proofing-costs-london) A realistic look at what damp proofing work typically costs in London, and the factors that affect pricing. ### [Insurance and Damp](https://syladamproofing.co.uk/guides/insurance-and-damp) What home insurance typically does and does not cover when it comes to damp problems and remedial work. Related ServicesProfessional damp proofing services related to this guide --------------------------------------------------------- [ ![Rising and Penetrating Damp](https://syladamproofing.co.uk/img/services/services_img02.jpg) ](https://syladamproofing.co.uk/services/rising-and-penetrating-damp) ### [Rising and Penetrating Damp](https://syladamproofing.co.uk/services/rising-and-penetrating-damp) Identify and treat rising damp and penetrating damp with surveys, remedial repairs, and internal restoration work tailored to the property. Worried about damp? 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