Chimney Damp

Dampness in Chimneys


Damp Proof Without the Need for Serious Reconstruction

Dampness in chimneys is a common problem and quite often many attempts at solving the problem fail due to misdiagnosis of the cause and/or incorrect treatments being used. There are two particular causes of dampness that are suitable for treatment by the Aquadry range of products.

The Problems

Penetrating Damp

A chimney stack is by its very nature exposed to the elements. A combination of wind and rain coupled with defective rendering, pointing and porous bricks allow this rain to be absorbed and permeate downwards, resulting in damp exhibiting itself internally.

Free Water

Actual water can enter the structure, should the chimney not be sealed/capped correctly or if the flashing has come away. Defects such as cracks and voids can also allow rainwater to enter through this vulnerable area resulting in internal damp areas.

The Solutions

Penetrating Damp

Assuming the structure is sound and free from defects, Aquadry Masonry Protection Cream can be applied to the brick faces and mortar to provide a colourless, textureless and residue-free protective barrier to penetrating rain. Using Aquadry in this application will give you in excess of 20 years protection. In some cases it might also be beneficial to inject a Dryzone DPC at the lowest accessible point in the chimney stack to mitigate moisture tracking down this route.

Free Water

Any obvious defects will need to be addressed. This might include repair or replacement of flashing and possibly the introduction of a cap or cowl. Pointing is often quite porous and over time is subject to cracking due to a combination of penetrating rain and a cyclical freeze-thaw process. This can be solved by repointing the chimney stack incorporating Aquadry Repointing Additive No. 1, or by using Aquadry Repointing Additive No.2 in areas prone to strong wind-driven rain.