Damp around chimney breasts

Damp around Chimney Breasts

Damp is very common around chimneys. This can be due to a number of reasons:

1. Chimney flashings leaking

2. Chimney needs re-pointing

3. Chimney not vented properly

4. Chimney not covered (thus allowing rainwater in)

5. Rising damp

1 and 2 need to be done from the roof and so this requires a professional or a competent DIYer. There are more sustainable alternatives to lead flashing like Z-led and UbiFlex. These are aluminium mesh products. Remember to use the correct mortar for the building. This might well be a lime mortar on older buildings.

3. Chimneys that have not been capped need to be vented top and bottom to dry out any water ingress. Vents therefore need to be in place if the chimney breast has been blocked.

4. There are different chimney pots and some of these are designed to stop rainwater from getting in whilst still maintaining good ventilation. If the chimney is not used then a simple removable chimney cap can be fitted that will stop rainwater, insects and birds from getting into it. This combined with a Chimney Balloon can be an efficient way of reducing heat loss through the chimney in winter.

If the chimney is still in occasional use then it is important to have a chimney pot that stops rainwater ingress. A T shaped pot or an appropriate cowling can either be used as a replacement or just as a bolt-on improvement.

5. The damp can of course be coming from below as well as from above. Appropriate damp proofing methods need to be used here (lime putty render, silicon cream injection into the mortar etc.)

For more advice and products please call the Eco Home Centre on 02920373094.


Rounded Developments Enterprises Ltd have endeavoured to ensure that the information contained in this report is accurate. However, Rounded Developments Enterprises Ltd. accepts no liability for the use of this information.

Statement of Vested Interest

Rounded Developments Enterprises Ltd are a well-recognised supplier of a range of sustainable building products and as such have a commercial interest in some of the recommendations contained within the report. In some cases, cost estimates have been given on the basis of current quotations for similar equipment supplied by Rounded Developments Enterprises Ltd, and may not be the only equipment available. However, it is our opinion that the study offers an appropriate level of detail in view of the resources available and information provided. The authors have no expectation of any order being placed with them and would welcome questioning of the choice and costs of any equipment.