When it comes to flashing your chimney, which material is best to use?
Traditionally, lead has been the go-to metal to use to create a strong, weatherproof seal for all types of roofing solutions.
But today, there are a number of lead alternatives that make flashing your chimney easier and less expensive.
So, in this week's blog, we are taking a closer look at exactly what lead flashing is and whether there is a better option out there...
What is lead flashing?
We already have a guide explaining exactly what flashing is and why we need it.
But for this article, we are going to look a little closer at lead flashing in particular.
Lead is just one material out of a few that is most commonly used for flashing chimneys. It has been favoured for so long because it is durable, malleable and strong. These are great properties for flashing, as it means it can easily be fitted to surfaces like roof tiles and brickwork while still providing a tight seal.
When choosing a lead flashing, you might come across ‘lead codes.’ These refer to the thickness of the lead, which is important to get right. Lead will expand and contract as temperatures change, so it’s important to get the right code to ensure your flashing doesn’t crack.
For chimney flashing, you will usually need code 4, code 5 or code 6 lead.
Is lead flashing dangerous?
Most of us know that lead as a substance can be toxic if it is ingested into the human body.
So, just how safe is it to fit onto your roof?
Lead has been used in our roofs for centuries, and is perfectly safe. Of course, you should always wear gloves when handling it and avoid touching your hands, mouth or face. Then, wash in cold water when you’re done.
When it comes to disposing of old lead flashings, you will be pleased to hear that it is in fact 100% recyclable! What’s more, it is actually one of the most efficiently recycled materials, so can be seen as a very sustainable option.
How long should lead flashing last?
Another benefit of using lead to flash your chimney is just how long it will last you.
When applied correctly, lead flashing can literally last you a lifetime - by which we mean up to, or even over, 100 years!
Things go wrong when the lead is laid without space to allow for expansion when temperatures increase. Nevertheless, if this splitting does occur, lead can still be fixed by welding it back together, or using flashing tape.
What is the cost of lead flashing?
Here at Trade Price Flues, you can find lead flashing for twin wall flues for less than £100, which is great value for money. However, lead can be more expensive than alternative types of flashing, which are sometimes also easier to fit.
For this reason, lead-alternative flashings have been growing in usage.
Are there any downsides to using lead to flash your chimney?
So, cost aside, are there any other disadvantages to using lead to flash your chimney?
Here are a few of reasons why you might want to use an alternative...
As we have already mentioned, it takes a certain degree of skill to correctly apply lead flashing. You must allow for thermal movement and be sure you have the correct lead code for your usage. It’s usually recommended that an experienced roofer applies your lead flashing.
As lead is widely recycled, it does carry a certain scrap value. So, it can sometimes be targeted by thieves, especially when used in large amounts.
Lead is a relatively heavy material, so for smaller structures, it might not be suitable. For example, if you were putting a flue through a shed or outhouse roof, something lighter might be preferable.
What are the alternatives to lead flashing?
We’ve touched on the fact that there are alternatives to lead flashing out there.
So, what exactly are they? And which is the best to use?
Introducing Dura Flash at Trade Price Flues
At Trade Price Flues, we are excited to stock a fantastic alternative to lead flashing - the industry changing Dura Flash.
Dura Flash makes flashing your chimney easier than ever before. Lead-free, highly stretchable and with outstanding self-welding properties, this highly UV and water resistant flashing is a fantastic alternative to traditional methods.
Ideal for twin wall flue systems, Dura Flue comes complete with a cone shaped hole to fit perfectly around your flue pipe, while the self-adhesive SabetoFlex membrane is stuck to the surrounding roof.
Dura Flue can be adhered to any sound surface without having to be overlapped from the top, plus it has a shape ‘memory’ - meaning it won’t try and snap back to its original position.
Along with being highly durable to heat expansion, it can remain flexible in temperatures down to -60°C! As it is so lightweight, it’s also ideal for smaller structures.
Take a look at the video below to see for yourself just how easy it is to use...
If you are flashing a conventional chimney stack, you can also buy rolls of SabetoFlex to apply as needed.
EPDM Chimney Flashings
Another alternative to lead flashing is EPDM flexible chimney flashings for twin wall flues. These are made from a type of synthetic rubber, which is highly elasticated plus weather and UV resistant.
One of the advantages of EPDM flexible flashings is just how inexpensive they are. They are also highly versatile and easy to fit. All you need to do is cut the right size hole in the rubber cone to fit your flue pipe through. The flexible base can then be sealed to the roof with silicone.
Here is some more information about how to apply a Dektite Ezi-Seal EPDM flashing…
Do you need chimney flashing supplies for your roof? Take a look at our full range online at Trade Price Flues!
If you’re not sure what you are looking for or need some advice, please simply contact us or use our live chat - we are always happy to help you find just what you need.
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