This project is presented by Property Repair Systems
Summary: How to detect and deal with damp in a chimney breast.
If you need any help with any type of Chimney damp problem or timber repair, Property Repair Systems will be pleased to give you completely free, no obligation advice on 0843 636 8164. The information you need may be in the project below, if not, call them.

Damp in chimney breast is dealt with in much the same way as damp elsewhere except that, because of tar and other chemicals, the salts are sometimes a little harder to deal with. The recommendations for this are below. When working on chimney breast damp in the loft please be very careful to strengthen the floor before walking and plastering on it.
A quick summary checklist: a 'damp meter' and surface thermometer are useful tools for this diagnosis - if not available use the back of your hand to assess the relative dampness of one affected area to another unaffected area..
Symptom:- White, fluffy salts, plaster possibly 'blowing' off the wall - 'efflorescence' - you have a water source which needs to be found and eliminated. Use our Water Leak Checklist (click here).
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Answer:- Salt Neutralizer might work if you can find and stop the leak, or the plaster may be too damaged and need replacement to our Specification.
Symptom:- Damp patches on the ground floor (at low level, right down to the skirting board) that come and go - you have 'hygroscopic' salts that are attracting moisture from the air.
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Answer:- You may have Rising Dampness, or your damp proof course may be 'bridged' by high outside ground, plaster on the inside or debris in the cavity (cavity walls only). Rectify any defects and if necessary inject Quick Cream at the correct level to form a new Damp Proof Course. The plaster will need replacement to our Specification.
Symptom:- Damp patches on or around chimney breasts - sometimes showing yellow or brown stains in wallpaper or paint - you have 'hygroscopic' chimney salts that are attracting moisture from the air, which may include tars and other chemicals from burning wood or coal.

Answer:- These 'salts' are very difficult to hold back in the wall, even with the re plastering to our Specification carried out to perfection. We recommend using Mesh Membrane - a type of dry lining - to allow you to re plaster using normal, lightweight plaster, with no risk of further 'salting'.
Products mentioned above:
Salt Neutralizer:- a clear liquid used to neutralize 'salts' in render, plaster or masonry, either to attempt to save otherwise sound plaster or as a preparation prior to re-plastering to our Specification. Apply two coats, wetting in between with fresh water.
Mesh Membrane:- easy to install dimpled plastic 'air gap' dry lining membrane, supplied in rolls like wallpaper. Designed to cover damp or salty walls and provide a fresh surface for re plastering with a modern lightweight plaster (usually 'bonding').

Quick Cream:- new, easy to install, cream damp proofing product - no pump required, no mess, no smell - includes injection nozzle extension. Designed to gently diffuse into the wall to form a water repellent layer - a 'damp proof course' (DPC). It is approved by the British Board of Agreement - BBA Test Certificate No: 02/3961 - as used by the professionals. The BBA is a Government Approved organization which has been testing building materials for over 30 years. Note - not all damp proofing materials have passed these tests - beware of cheap imitations).
If you need any help with any type of Chimney damp problem or plaster repair, Property Repair Systems will be pleased to give you completely free, no obligation advice on 0843 636 8164.