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Frequently Asked Questions 

All our frequently asked questions can be found below including "how much does it cost to line my chimney", "how long does Eldfast Chimney Lining last" and "Can I use a stove with Eldfast chimney lining". Simpy look in one of the categories below or use our quick search tool by clicking the magnifying glass.

Our customer service team are also on hand should you have any questions by calling +44 (0) 1527 857814.  

  • Can I use Eldfast with a stove installation?
    Eldfast creates a gas tight chimney lining system and is classified as a dry lining system. As such the material is not designed to be a moisture barrier. As a stove will connect to a smaller flue connection below the register plate this can also create turbulence due the change in size. As such we would suggest a stainless steel flexible liner or equivalent for stoves. However if your chimney requires structural support you can combine both a stainless steel frlexible liner with Eldfast ceramic lining for the ultimate chimney protection, lining and safety. Ask our staff for more information.
  • How often do I need to sweep my chimney?
    Eldfast is very resilient but a chimney can be blocked depending on the fuel used or configuration. We recommend the chimney is swept once per year as a minimum, but should you experience problems ensure the chimney is clear before re-lighting your fire.
  • How long does Eldfast chimney lining last?
    Eldfast has a life expectancy of 50-60 years with a guarantee of 25 years.
  • Is Eldfast Chimney Lining suitable for thatch properties?
    Eldfast has been used on a growing number of thatch properties and provides a strong heat shield that conforms to Document J of the building regulations. Eldfast acts as an insualative barrier that at test reduced the 700°c gas temperature to only 59°c by the time it had passed through the lining and outer brick work. We will always recommend that you have confirmation from your insurance that this method is suitable and acceptable in advance. However many Thatch insurers are aware of and accept Eldfast as a lining solution for thatched properties.
  • Is Eldfast suitable for Listed properties?
    Eldfast has been used on a number of listed properties including those of the National Trust, The Landmark Trust and English Heritage portfolios. As Eldfast does not significantly reduce the chimney size the lining does not alter the construction of the chimney. Your conservation officer will need to be consulted prior to installation but we can provide details on the process and system if required. One of the key points with any open fire or stove over 5kw in a listed building is air ventilation. If there is not permanently open air vent in the room the fire is in one will need to be fitted for the works to be signed off.
  • What areas do you cover?
    Eldfast Ltd covers the UK and Internationally. We cover all areas ourselves and have a network of installers. Depending on your location there may be additional costs for travel and quotations depending on availability. Where an overnight stay is require the accomodation cost would be added to the quotation unless you are supplying this yourself.
  • What is Eldfast made from?
    Eldfast is a ceramic compound with a mix of brick and china clay and 30% recycled materials. It arrives in powdered form, but when mixed with water and allowed to set and is cured becomes a solid ceramic lining and a permanent coating for 50-60 years.
  • What is the guarantee?
    Eldfast material has a guarantee of 25 years with a life expectancy of 50-60 years.
  • What does the guarantee cover?
    You can find out more information here
  • Do I need an air vent?
    It will depend on what is installed. Anything over a 5kw stove will require an air vent for sign off. Typically for Eldfast as the chimney is not significantly reduced a 100cm² would suffice pending a survey. This can cause a complication for Listed Properties so speak to our staff on 01527 850513 should you have any queries.
  • Do I need a CO Detector and if so where?
    Yes, for your installation to be signed off to building regulations standards your would need a CO detector. This can be supplied by us or yourselves. Our surveyors and engineers will determine where the CO detector would need to be positioned.
  • Do you need to break into my chimney?
    95% of chimney lining with Eldfast does not require us to break into the chimney breast. If you have tight bends or we find constructional issue during the lining process this may be required. The midfeather (brick skin between flues in a stack) can break down due to lime mortar errosion. If this has occured we may need to break in (usually within the loft space) to make repairs so the chimney can cope with the balloon pressure as the lining takes place. If this does occur please chack your quotation in advance for the abortive call charge as if all works cannot be completed in a day there may be an additional cost for chimney repairs prior to lining. If you have a concern please speak to our customer service team or our surveyor.
  • How long does the installation process take?
    Most Eldfast installations are carried out in half a day to a day when working on standard chimney sizes unless repair work is required prior to the lining taking place.
  • How soon can I use my fire after installation?
    There is a curing process due to the ceramic material which we begin when lining has been completed. After which you complete the curing with a 2kw electric heater followed by gradually larger fires over a 2-3 day period. This process is vital and should be carried out immediately after lining has been completed to ensure you chimney is lined correctly. Please ensure if you have had scaffolding errected that it has not been removed until the chimney has been thoroughly tested and cured. Should you find the issue has not been resolved our engineers can return and re-skim the lining as part of the initial cost.
  • Is Eldfast Chimney Lining messy?
    Most of the lining work takes place on the chimney top. Our engineers take great care to ensure that the area is covered well and the chimney opening is also covered. If you can ensure your chimney is swept prior to our arrival and fragile or valuable items are cleared away from the fireplace this will help ensure the process is as clean as possible.
  • Is Eldfast Lining tested after installation?
    As the material is still wet until you have carried out the curing process testing cannot be carried out on the day. We can either include a separate charge for a retrun visit to smoke pressure test your chimney or you can simply test it yourself as part of the curing process. If you find your chimney is leaking after the installation our team can simply return and re-skim the lining as part of the warranty.
  • How do I "earn as I burn"? "
    Eldfast Ltd invests in various forms of marketing to ensure that you find out about our chimney lining system and many of our customers refer our services to their friends. As we would prefer to pay our customers than a marketing agency we offer a £100 thank you that you can keep yourself or pass onto your friend for every lead that becomes a sale. Simply email your friends / colleagues / customers details to us advising that you are referring them for Eldfast lining (please get their permission first) and should they proceed with the quotation with ourselves or a contractor supporting the scheme you will be sent a thank you cheque.
  • How much does Eldfast Cost?
    Eldfast, unlike a lot of chimney lining solutions conforms to the shape of your chimney. As such the cost is directly effected by the internal chimney size, length and whether there are voids or holes to fill in prior to lining. If you fill in the form here we can provide an estimate or you can contact our team for guidance over the phone or to book in a survey.
  • Is there a cost involved to get a quotation?
    This will depend on your location and whether Eldfast Ltd or one of our trained contractors carries out the work. Quotations are free for Eldfast within an hour of our headquarters. However where Eldfast Ltd are carrying out the installation this is usually refundable should you proceed with the installation to the value of £2200+vat or more. The cost for the survey is usually from £75+vat upwards depending on your distance from our offices.
  • Why does Eldfast cost more than some other chimney lining solutions?
    Eldfast is a permanent chimney lining solution designed to withstand very high temperature, resist acid attack and create a gas tight, fireproof barrier for your chimney guaranteed for 25 years with a life expectancy of 50-60 years. To achieve this the materials used costs more than those used on many other mass produced lining systems. However when comparing life expectancy and the risk of replacement after a chimney fire to other lining solutions Eldfast is very good value for money. Eldfast is also a product that needs to be installed by trained installers and takes time to master compared to more simple, temporary lining options.
  • Can we use a cherry picker instead of scaffolding?
    As we will need to go up and down regularly to get more material and winch it up the chimney cherry pickers are not ideal and can increase the labour cost potentially. However, in the event that scaffolding is not practical for the property we are happy to consider the use of a cherry picker instead. Please note the warranty does not include access equipment so you would need to re-hire the cherry picker should we need to return for repairs or re-lining.
  • Can Eldfast Ltd supply the scaffolding or cherry picker?
    We certainly can, however unless you are in our local area you may find it easier and cheaper to deal with a local access equipment company yourself. Our team can advise the requirements on your quotation to make sure you know what to ask for.
  • Will I need Scaffolding?
    If the chimney height is above 10 metres, the stack location is not close to the ridge and within 1200mm height from the ridge or if there are connecting ridges, external roof windows e.t.c that prevent a ridge platform being used scaffolding would be required. All thatch properties will require scaffolding. Please also note that the scaffolding must remain in place until you have followed the curing process and tested the chimney. We would recommend scaffolding is installed 2-3 days before we install and at least 1-2 weeks afterwards in case our engineers need to return and re-skimany areas.
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