It’s getting hot out there!

As the heat build in summer, some seriously strange things start taking place in your chimney.

Some of these are very visible, while other things usually only occur out of sight.

Here’s what to look out for…

#1 – Room Starts Smelling Of Soot

Chimneys are smelly places at the best of times. Thankfully though, most odours never get noticed.

This is because, under normal circumstances, chimneys work by using the natural environment and specific construction methods to warm air from the fireplace area, up the chimney and out of your home into colder air.

But in summer, that natural upward draught can actually REVERSE, meaning air pushes down the chimney. This is because, unlike the rest of the year, the temperature of the outside air is warmer than the air inside your home.

So if you have an open fireplace, this could mean any smells start wafting into the room instead. And obviously, the dirtier the chimney, the stronger the smell.

#2 – Dust and Debris Falls Down The Chimney

As well as being smelly, chimneys are also very dirty places – thanks to years of coal dust, ash and loose mortar made up of sand, cement or, in older properties, lime.

When temperatures rise, traditional brick chimneys start ’drying’ out from the heat. Previously hard mortar becomes brittle or crumbles into sand, and falls down the chimmey.

And when the summer ‘reverse draw’ takes place, it can actually help push bits of soot and dirt down your chimney as well.

A few bits of mortar in the grate are nothing particularly to worry about.

But larger amounts (as in the photo above) could indicate something else, such as a trapped bird (another summer phenomenon!) so its always important to get it looked at.

#3 Humidity Levels Rise – Bad News Especially For Chimney Liners

In the case of closed appliances (I.e. – woodburners, multi fuel stoves, coal boilers etc), the amount of humidity in the flue in summer is likely to be higher than normal. 

In some much more extreme cases, you may get tiny bits of condensate on the inside or on top of your stove.

However, most of the time, you’ll rarely notice it as it stays well within the chimney, mixing with all that no-so-lovely soot and mortar.

And if you’ve got a metal chimney liner installed, that’s obviously not great. Because when you have water, mixed with a corrosive substance (soot), on any sort of metal, it can cause corrosion.

So – what’s the solution?

Step #1 – Get Your Chimney Swept In Spring/Summer

A swept open fire chimney will not only help stop your room smelling, but also stop excessive debris from falling down. 

For those with lined chimneys, the soot needs to come out of the flue ASAP. As we said, soot is corrosive and, when mixed with vapour from the increased humidity, it really can speed up the corrosion process.

Step #2 – Ventilate Your Chimney

For logburner and stove owners, we always advise you open all air vents on your stove, and even leave the door slightly ajar, to aid ventilation.

If you have an open fire, it can be a good idea to open the damper if you have one. It’s tempting to keep it closed to stop any debris falling down.

But good ventilation – coupled with a freshly-swept chimney – is the best safeguard of all.

Want to know more? Watch our master chimney sweep technician David explain…