Chimney waterproofing that lets the brick breathe in Health District

The crown has its own coating

The concrete or masonry top of a chimney sheds water from the flue outward. When it has fine cracks, a crown coating made for that purpose may be used. That is a different product from a face repellent, and it belongs to crown repair.

We check the crown as part of preparing for waterproofing, because the top has to be sound first. If it needs coating or rebuilding, that appears as its own item. The face treatment is then priced separately, and each has its own reason on the estimate.

What happens on the application day

On the application day, we confirm the forecast, check that the masonry is dry and set up access. Glass, metal, roofing and plants in range are covered or masked. Cars and furniture have been moved.

The product then goes on, face by face, by the method its data sheet sets. Overspray is dealt with as the work proceeds. When the product has set enough, coverings come off and the area is cleaned. We go through what was treated and hand over the written record.

What a repellent will not do

It helps to be clear about the limits of a treatment before paying for one. A penetrating repellent is not a repair, and the list below covers what it leaves untouched.

Each of those needs its own repair. Our estimate lists them separately, so nobody expects the treatment to do a job it was not made for.

• Close cracks, open joints or gaps at the top
• Strengthen crumbling brick or soft mortar
• Stop rain falling down an open flue
• Fix water getting in at the roof junction

Trying the repairs alone first

Brick industry guidance suggests a sensible order: make the repairs, then wait and see whether the water problem is already solved before deciding on a coating. Often the repairs do most of the work.

If you prefer that approach for your chimney in Health District, we price the repairs now and leave the treatment as an option for later. After some heavy rain, you can look at how the chimney behaves. If faces still soak up water, treatment can follow. If not, you have saved the cost.