FAQ’s
Can I fit a damper to a gas open fire?
NO! You must not fit a damper to a gas fire, and if you fit a gas appliance to a flue which has a damper, that damper must be disabled or removed!! This is a legal requirement, and is obviously in place to minimize risk of Carbon Monoxide poisoning. There is no great risk of CO from an open wood or coal fire – you will very soon know if you try to light a fire with the damper closed. Care should be taken, however, never to close the damper until the fire is completely out and cold.
Are your dampers “air tight”?
My dampers will reduce chimney draught to an imperceptible level, but they are not airtight. It is best practice to allow a little airflow through the flue to prevent damp and condensation. A tiny bleed of air will also help if anyone should close the damper before the fire is completely dead. Finally, a working chimney is no place for any contraption built with zero tolerances, as soot and heating/cooling cycles will soon jam the mechanism or prevent it from closing as intended – simple foolproof engineering is the order of the day!
Can I control the fire with your dampers?
As a rule I make dampers that have just two positions – fully open and fully closed. I occasionally get asked to make adjustable dampers – This can usually be achieved but in my opinion it serves very little purpose, as you’re very unlikely to get any control over an open fire with a damper. In practice, as you progressively reduce the flue aperture with the damper, the velocity of the air/smoke going through it simply increases, until you get to the point where it cannot get a sufficient volume of air through the aperture and the fireplace starts smoking into the room.
Where is the damper installed?
Although both variants can take different forms to suit the situation, chimney dampers fall broadly into two categories: Fireplace dampers which are fitted just above the lintol of the fireplace, and chimney top dampers which are fitted to the top of the chimney stack and operated from the fireplace via a stainless steel cable.
Both systems work very effectively to reduce draughts.
The chimney top damper has the benefit of keeping birds, rain, debris and cold air out of the chimney, but may not be practical if safe access to the top of the stack for measuring/fitting is problematic, or if the path of the flue is too tortuous to guarantee ease of operation.
The fireplace damper, on the other hand, does not require access to the top of the stack. It may, however, not be a practical solution for very large “inglenook” fireplaces, or where the shape of the flue gather is very awkward. Measuring and designing fireplace dampers that will open and close without fouling the walls of the flue and cause minimal obstruction in the open position can be quite tricky, and fitting them requires a bit of flexibility and a willingness to get covered in soot, cobwebs and brick dust!
Neither form of damper should not cause any problems for a competent sweep.
Yes – I’ve sent lots of dampers out by courier for D.I.Y. fitting or for builders to fit. If you wish to do this, though, you will also have to take responsibility for measuring up and specifying the damper for your situation. The information on this site should help, and I try to give as much advice as I can by email or phone if needed.
Can you make a damper for me to fit myself ?
I’m happy to visit your home/site to assess and advise*, but please bear in mind that I’m a one man business, so depending on workload I may not be able to come out for a week or two. I may also have to charge for surveys that are outside my immediate area. The fee is likely to be £125.00 if I estimate up to a half day to travel/survey or £ 250.00 for closer to a full day. This is to partially cover my travelling expenses and lost production time, as well as including my consulting time and advice (sometimes I travel some distance, only to discover there are such major problems with the fire/flue that all I can do is advise on remedial work / alternative appliances. When this happens I can’t afford to lose a day’s work and put right the builder/architect/former owner’s follies for free – Even if the survey does result in a job, as a rule there is not enough profit supplying and fitting a damper to absorb the costs of survey more than a few miles from home, so survey costs do make up a proportion of the total bill, and distance from my workshop impacts both survey and installation costs.
As a rule, Victorian tiled or horseshoe type insert fireplaces, and small fireplaces with cast firebrick backs are not practical/economically viable propositions for me, so I will generally not travel to survey them. If not designed to have a damper originally, they’re fiendishly difficult/risky to fit to without damage. If they were designed with, and are missing an original damper, I may be able to make you a steel replacement, if you can send a template.
An up front survey fee can usually be avoided if you can provide a few photos, and rough dimensions before I visit. I can then give a rough estimate of total costs before surveying, and we can agree in principle that work is likely to go ahead if the estimate is confirmed.
If you or your situation require a chimney top damper, I will need safe access to the top of the chimney stack both for the survey and fitting.
*As a rule I prefer not to work in Central/South London, or at properties without off road, or reliable adjacent streetside parking suitable for a van. Obviously I’m still very happy to make and post out dampers to your specifications for diy/builder fitting, but as long as I have enough jobs with straightforward access/parking to keep me busy, I’d rather concentrate on those!
I want you to quote/adviseon a damper –what do I do?
Obviously there’s a pretty wide range of costs, reflecting the vastly different fireplaces I work with. As I write to update this site (February 2022) costs of steel, stainless steel, and everything else I use in my work are all going up, so estimating costs is harder than ever, I’m afraid.
As a very rough guide, fireplace dampers, which are generally made of mild steel, and a comparatively simple construction, range from £180.00 to £400.00 to supply – fitting will be another £ 175.00 to £350.00 depending on distance to travel and trickiness of the job. Typically, to survey, make and install a medium sized, fairly straightforward damper within 50 miles or so of Milton Keynes might cost £500.00 - £600.00.
Chimney top dampers are usually made from stainless steel, and are more complex to design and tune, so costs will typically be from about £350.00 to £600.00. Fitting, again from £ 175.00 to £350.00 BUT there may be extra costs associated with providing safe access to the chimney top.
On properties with multiple fireplaces/chimneys to assess, costs per installation are generally reduced as the travelling/survey cost is split between them.
Fitting estimates apply to locations within South East / Midlands.
How much do they cost?
Not really – one of the benefits of enclosed stoves is that even when they’re not burning, they’re saving you energy by minimizing the flue draught. When they are burning, modern stoves are controlled by adjusting the air intake.
If this does not give sufficient control as a result of either poor seals or excessively strong chimney “draw”, you will find retro – fittable flue pipe dampers and draught stabilizers are available “off the shelf” from firms like Stovax.