On this page we would like to show you how our chimney maintenance services works and what we do to chimneys to make them as good as new.
The first thing we do is identify any problems with the chimney. Generally we do this with the help of one of our cherry pickers to survey the chimneys, using the cherry picker we are able to get up close to see the condition of all the important parts of the chimney. We always look at whether or not the chimney has open chimney pots, we look at the condition of the concrete flauncing / crown on top of the chimney, we then look at the condition of the mortar pointing between the brick joints of the chimney and finally we look at the condition of the flashings and soakers around the bottom of the chimney.
Any problems found we photograph then send the photos along with an explanation of the problem to our customer via e-mail.
One of the first things to start to corrode on at chimney is the concrete flauncing on top of the chimney. Our first job when maintaining a chimney is to remove any loose or weak concrete.
If the chimney is being re-pointed the old chimney pointing needs to be ground out.
To ensure the new pointing is strong and adheres well to the exiting brickwork it is important that the chimneys brick joints are ground out to a depth no less than 20mm.
Once this has been done the mortar dust is blown out of the brick joints with a blower and the brickwork is dampened down.
Using a mortar gun, mortar is injected into the brick joints of the chimney. We like to use mortar guns for two reasons, the first is that it injects mortar deep into the chimneys brick joints ensuring they are full up with mortar. The second reason is that filling brick joints with a mortar gun is much faster than scooping it in with a trowel or striking iron.
Once the brick joints are nice and full, the mortar joints are struck off to leave a smooth water tight finish.
At DJI Property Services we call the top of the chimney the flaunce. This part of the chimney can go by some other names depending on who you talk to, it is also known as the chimney crown or chimney benching.
The chimney then receives a new concrete flauncing. We use a 1 part cement 3 parts sharp sand concrete mix for flauncing the tops of chimneys. As the top of the chimney is very exposed to all the elements it's important the concrete is strong.
It is also important the flauncing extends to the very edge of the chimneys brickwork to prevent any water that falls on top of the chimney from running down into the chimneys brickwork.
When chimney flues are no longer in use, preventing water getting down the flues can help prevent future damp problems on internal chimney breasts. When capping off chimney flues it is important to make sure airflow through the old flue isn't restricted otherwise condensation can form inside the redundant flue and show up inside the property as damp. To prevent restricted airflow the top of the chimney should be vented.
This can be done in a number of ways. The old chimney pots can have cowls installed over the top of them, cowls prevent water getting down the flues and have ventilation holes in the side of them.
If the chimney pots are in poor condition we often recommend they are removed. If the chimney pots are removed they can be replaced with ridge tiles, the ridge tiles will prevent water getting down the flue but an arch is left on one side of the ridge tile which allows for ventilation.
Air bricks can also be installed into the side of the chimney to allow for airflow.