Wood Burning Properties

A quick guide to wood burning properties

There are a many types of wood to choose from, all of which have their own burning qualities and properties. Although there are references to burning green wood here ; to get the most efficient and effective ‘burn’ in your wood burning stove, only very dry (at least <20% moisture) wood should be used. The following is a small guide only and is by no means comprehensive.

The table below shows the types of woods and their burning properties.

AlderProduces poor heat output and it does not last well.Poor
AppleA very good wood that bums slow and steady when dry, it has small flame size, and does not produce sparking or spitting.Good
Ash*Reckoned by many to be one of best woods for burning, it produces a steady flame and good heat output. It can be burnt when green but like all woods, it burns best when dry.Very good*
Beech*Burns very much like ash, but does not burn well when green.Very good*
BirchProduces good heat output but it does burn quickly. It can be burnt unseasoned, however the sap can cause deposits to form in the flue with prolonged use.Good
CedarIs a good burning wood that produces a consistent and long heat output. It burns with a small flame, but does tend to crackle and spit and the sap can cause deposits to form in the flue with prolonged use.Good
CherryIs a slow to burn wood that produces a good heat output. Cherry needs to be seasoned well.Good
ChestnutA poor burning wood that produces a small flame and poor heat output.Poor
Firs (Douglas etc)A poor burning wood that produces a small flame and poor heat output and the sap can cause deposits to form in the flue with prolonged use.Poor
ElmIs a wood that can follow several burn patterns because of high moisture content, it needs to be dried for two years for best results. Elm is slow to get going and it may be necessary to use a better burning wood to start it off. Splitting of logs should be done early.Medium
EucalyptusIs a fast burning wood. The sap can cause deposits to form in the flue and can increase the risk of a chimney fire if burned unseasoned.Poor
Hawthorn*Is a good traditional firewood that has a slow burn with good heat output.Very good*
HazelIs a good but fast burning wood and produces best results when allowed to season.Good
HollyIs a fast burning wood that produces good flame but poor heat output. Holly will burn green, but best dried for a minimum of a year.Poor
HornbeamA good burning wood that burns similar to beech, slow burn with a good heat output.Good
Horse ChestnutA good wood for burning in wood stoves but not for open fires as it does tend to spit a lot.  It does however produce a good flame and heat output.Good (For stoves only)
LaburnumA very smokey wood with a poor burn.Poor do NOT use
LarchProduces a reasonable heat output, but it needs to be well seasoned. The sap can cause deposits to form in the flue with prolonged use.Medium
LaurelBurns with a good flame but only reasonable heat output. It needs to be well seasoned.Medium
LilacIts smaller branches are good to use as kindling, the wood itself burns well with a good flame.Good
MapleIs a good burning wood that produces good flame and heat output.Good
OakBecause of its density, oak produces a small flame and very slow burn, it is best when seasoned for a minimum of two years as it is a wood that requires time to season well.Good
PearBurns well with good heat output, however it does need to be well seasoned.Good
Pine(Including Leylandii) Burns with a good flame but the resin sap can cause deposits to form in the flue and can increase the risk of a chimney fire.MUST be well seasoned.Good (with caution)
PlumA good burning wood that produces good heat output.Good
PoplarA very smokey wood with a poor burn.Very poor
Rowan*Is a good burning wood that has a slow burn with good heat output.Very good*
Robinia (Acacia)Is a good burning wood that has a slow burn with good heat output. It does produce an acrid and dense smoke but this is of course not a problem in a stove.Good  (For Stoves only)
SpruceProduces a poor heat output and it does not last well.Poor
SycamoreProduces a good flame, but with only moderate heat output. Should only be used well-seasoned.Medium
Sweet ChestnutThe wood burns ok when well-seasoned but it does tend to spit a lot. This is of course not a problem in a stove.Medium (For Stoves only)
Thorn*Is one of the best woods for burning. It produces a steady flame and very good heat output and produces very little smoke.Very good*
WillowA poor fire wood that does not burn well even when seasoned.Poor
Yew*A good burning wood as it has a slow burn and produces a very good heat output.Very good*

In addition there are also the compressed reclaimed ‘eco’ type of logs and briquettes which do tend to burn well and for a decent length of time because they are dense and very dry. You should try to choose a product that does not break apart too easily.
In a nut shell you should always use hard woods over soft woods.

Moisture Meters

The single worst predisposing cause of chimney fires today is wet wood. The recommended level of moisture is less than 20% to avoid chimney fires. You can read more about moisture meters in our site here

This guide was originally taken and adapted from http://www.flamingfires.co.uk/which-wood-burns-best.htm

BIRDS NESTS

Two types of birds are most common in chimney problems, starlings but more often jackdaws (small crow with silver streak on its ears). From April till July (although problems often occur beyond these months, as jackdaws are very territorial and can hang about all year) it is the jackdaw nesting season.
You should never underestimate these birds as they are surprisingly intelligent and some of the most determined when it comes to procreation & nest building.
It is surprising how many cases of birds nests i see just driving around , all too often a bricked up fireplace hides a multitude of sins and takes the owner’s mind off the flue completely.
Unfortunately in the 1980’s many gas fire fitters ran amok fitting fires without ensuring the flues had been swept (and often without a proper GC1 or GC2 fitted on top of your chimney) so if you have a nest above your gas fire it is often the case a few bags of soot will come out too and you may still need the correct gas cap fitted.

What you need to consider when you have this problem

Firstly, so what exactly are you up against ?
The crows nests that can be seen in trees, are in this case; built on top of a structure akin to a beavers dam (which is often at least 6-10 ft deep or more) used to provide a support for the nest.
The worst case that i remember was an old big building in Barassie that had multiple generations of jackdaw nests on top of each other. The runs in the chimneys were convoluted hindering removal of the nest material and so the only course of action was to open up the wall above in the loft space.
We eventually removed 13 bin-bags of nesting material over a 9 hour period with little to no time for resting, removal is ALWAYS hard physical and labour intensive work.
To try to put a time figure on nest removal is kind of like asking how long is a piece of string, but on average with a wee bit of luck a nest takes between an hour to two hours to remove and will likely yield at least two or three bin bags full of stuff.

It gets worse too

If left unaddressed the worst case scenario for your house, is that it can and will eventually cause dampness problems that when severe enough will threaten your house.
Nests act as sponges for the rain which will eventually soak through into your inner and sometimes outer walls. Oftentimes, i will see the signs of dampness above the affected chimney fireplace where the walls meet the ceiling and this may be in the room directly above too, depending on the height of the nest and run of the flues.
If your building was built prior to the mid 1950’s then the mortar between your bricks/stones is made from sand and lime not concrete. This is very susceptible to the sulphurous acid made when the sulphur from coal soot is dissolved in rain coming into your chimney. If your flue gets damaged enough you will eventually need to get a liner fitted to be able to use it again, that’s rubble allowing of course.

What we can do for you

Firstly, we remind you that as long as there are eggs or chicks in the nest it is illegal to remove them unless you have a special license. So from April onwards you will need to wait till the birds have left (as you can read here RSPB Nest removal regulations.)
The most relevant parts are as follows, “The breeding season for Jackdaw’s is April – July. Therefore, if you are unsure there is a nesting Jackdaw, then the best advice is to wait until the end of August – September. Outwith April to July or if it is an old abandoned nest we will able to remove it completely for you.

We guarantee your birds nest problem will be removed completely as proven by our free CCTV inspection (minimum value £60) that you will be shown live at the time and your also chimney swept efficiently.

Please remember that this work can be messy because we need open access to the fireplace to create the forces necessary to remove the blockage. We cannot always close it to the same degree as when we are doing a normal sweeping job. So, you should consider covering your floors, furniture and perhaps removing things from the room in advance.

We charge minimum one hour inclusive (£100) and afterwards by the half hour so you only pay for exactly how long the job takes, no more no less.
We will remove all soot and nest materials efficiently and completely as shown by CCTV.
If we can do it in an hour or less it will be done because we do NOT mess around, or take breaks and we keep ourselves fit & strong for this purpose.
Supplying and fitting a bird cage is mandatory too because it is for your benefit… we simply don’t want to have to do the same job twice.

Using stove thermometers to ensure optimum efficiency

 

Using your newly acquired wood/multifuel stove will give months of long , easy  & warm cosy days where you can lounge around just enjoying yourself. However, as with all things that are subject to temperature variations , maintenance checks are essential giving you peace of mind and the satisfaction everything is running under optimum conditions.

Often times these, “checks” may seem as if they might drag you out of your comfort zone but the good news is once you’ve attached it to the stove top or flue pipe arising from it , using a stove thermometer is as simple as making regular readings.  They come in a few varieties and can be wire , hose clipped or magnetically attached.

 

stove thermometer

Figure:1 Typical stove thermometer (with optimum operation zone)

They are used primarily to avoid over firing , (the resulting extreme temperatures create bad fuel efficiency) and are operated by having an eye gauge in both °Celsius and Fahrenheit. Keeping your stove burning in the Correct range of 115°C – 245°C or  (240°F – 475°F) will ensure the safest operation , whilst simultaneously giving maximum fuel economy.

Running Too Cool

Allowing your stove to reach burning temperatures below 115°C or (240°F) will lead to incomplete combustion creating carbon monoxide, tar, soot and creosote.

Creosote itself , is a condensation residue of coal and/or wood particles , hydrocarbons , gases and other airborne debris. It is formed as gases cool , for example when air in a chimney is not hot enough to push the particles out. Its appearance is of a thick hard black shiny goo which reduces the bore of the flue by sticking to the inner bore.

Running Too Hot

When you allow your stove apparatus to run above burning temperatures of 245°C or (475°F) you risk damage to your flue/liner/cowl and possibly warping your baffle plate.  A significant increase in the risk of chimney fires is created, especially if there has been creosote build up.

Read our other articles under ‘stoves’ or burning ‘wood’ to gain the knowledge you need to use your appliances to maximum efficiency under safe conditions. Also Please remember a significant part of this maintenance strategy is to get your solid fuel heating appliances swept at least once a year by your chimney sweep.

You can buy thermometers and wood moisture meters here Here