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Thatched Roof Focus: Flue Inspections

Norwich-based Robbie Dickson at Thatch Fire Prevention has provided flue surveys for One Broker clients since October 2019. Since then, he has inspected nearly 300 flues at thatched-roof properties up and down the UK. He explains the importance of flue surveys for thatched homes and provides some top tips on keeping your flues in good working order.

Tell us about flue surveys. What are you looking for?

We check the flue liners at thatched-roof properties with wood burners to make sure they’re suitable and that, if they need additional insulation, they have it.

We put a camera up the flue, normally through the appliance, to get a total view all the way to the top, then we record the whole flue on the way back down. We’re looking for any defects in the liners.

Some flues need additional insulation to the outside so, after we’ve done the CCTV inspection, we will try and get into the chimney void to see what the required insulation is. 

On occasion, we can’t get into the void but installers are meant to leave data plates as part of the building and HETAS regulations. These are either in the fire surround itself or by the electrical fuse board. This should detail who did the work, what they did and when they did it. 

How long does a flue inspection typically take?

Normally my videos are around 8-10 minutes long for an average flue, so it’s probably about a 10-minute inspection internally, fully recorded, and then, if required I’ve got to inspect the outside of the liners if required as well. 

Pre-COVID, it was wonderful; the homeowner could look over my shoulder when I did the CCTV survey. Now it’s a little bit more difficult. At the moment, I tend to do the inspections alone, but if I find any issues, I work out how I can show them the issue, so they can understand it. It’s a lot easier seeing something than me trying to explain it. 

Do you talk through the next steps with them?

Definitely. I recommend stovepipe thermometers and a product called Hotspot. Hotspot is basically a powder flue cleaner, which helps break down the tars and creosotes. The main aim is to stop tar and creosote from building up because this can catch light in the flue. 

If you’ve got a heavy build-up there’s obviously something wrong. You’re either not burning the wood hot enough or you’re burning unseasoned wood or wood with a high resin content, or something like that. If you’re burning something you shouldn’t it can show up in the videos.

Read more: How long does a thatched roof last?

How frequently should thatched-roof properties have flue inspections?

It really depends on the liner type, but generally between three and five years. Basically, they’re important because liners can and do deteriorate over time. Even stainless steel corrodes, especially if you haven’t got a cowl on top of the chimney; water will go down the liner and damage it over time. Regular inspections are key because things can change. 

I recently saw a property where a liner had become detached from the chimney pot and dropped about 1 metre down the chimney. It was pointing directly at the brickwork within the chimney stack. That’s really dangerous because it’s right next to where the thatched roof is. The first thing I did was look back at an old video from a previous survey, which showed the liner was fine so the damage occurred within the last five years. Having spotted it, the homeowner could arrange to have it fixed.

Do you have any tips for property owners if they want to keep their thatched roof safe and in good condition?

Yes, the key is to burn good wood at a good temperature. 

I highly recommend that homeowners have a stovepipe thermometer that goes on the pipe just above the stove. They’re a really useful tool and cost £20. Many are on a magnet and can be popped onto the pipe.

It gives you an idea of whether your burning temperature is too low, which will create the tar, soot and creosote build-ups. The other side of the scale is too hot. 

You shouldn’t burn paper or cardboard to start the fire either. Light it with kindling or firelighters because burning paper can get dragged up the flue very quickly. 

The other thing, which is a bugbear for a lot of thatched property owners, is regular sweeping in line with the insurers’ requirements. You should get your chimney swept at least twice a year if you’re using your stove. The sweep should also advise on the type of material he’s getting out of the flue. If they’re getting tar and creosote out they should tell you. 

Protect your thatched roof

Give us a call on 01603 788050 to find out more about Thatched Property Insurance from One Broker. 

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