Seasoning Wood in a Cellar
Danny Monaghan
We have a small room in our cellar, about 4' square which I want to use
as a wood store. If I had a load of non-seasoned wood, would it be the
wrong place to store it while it seasoned? The room isn't ventilated
beyond a low level vent in the door and an air brick at high level
through to another similar sized room where the coal chute goes.
I could fit more ventilation if that is what would be needed, but it may
be easier just to buy seasoned wood.
Cheers
d...@gglz.com
> Is this a bad idea?
Yes. Good air circulation is essential. Where timber is air dried
commercially, it's sticked to separate the boards and stored in either
open-sided or slat-sided buildings. Without good air circulation,
there's a good chance you will get fungal attack and possibly warping
from uneven drying.
robgraham
Yes Danny - I have to agree. You would be better storing it outside
sticked with some sort of open cover over it let the wind blow
through.
Rob
The Natural Philosopher
firewood, but for joinery you really want it inside the central heating
zone a few months before cutting.
The Natural Philosopher
small leaks) and it dries pretty well.
There must be leakage into te rest of the house as well. IME the real
issue is keeping the rain off it.
We pulled some 5 year old scaffold planks up today..the ones that had
been in contact with soil had rotted, ut just expose to the wind and
rain - not much rot at all. Thats with NO cover at all
The actual rate of moisture loss from wood is really low. I don't think
ventilation is as much an issue as just keeping the air RH below 70% or so.
Which in any case is what it gets to on a wettish day outside under cover.
George (dicegeorge)
wouldnt you be bringing all kinds of wood bugs into the building?
if its building wood
then someone just said it should be at room temperature
so it doesnt shrink or expand when its fitted to a room..
Dave Liquorice
> Is this a bad idea?
Probably I've yet to come across a cellar that isn't damp... You do need
lots of ventilation, you'd probably have to add some forced ventilation
rather than just bigger holes.
--
Cheers
Dave.
The Natural Philosopher
Thermal coefficient of wood is very low, but it absorbs water like
nobodies business
Stuart Noble
It's reckoned that wood dries outdoors to a moisture content of 17% in
winter, and 15% in summer. This is what you expect joinery quality from
a timber merchant to be. But for indoor stuff and furniture, it should
ideally be around 10%, which is only achieved by keeping it indoors for
a few weeks. In an ideal world you wouldn't plane the timber until then
The Natural Philosopher
100% agreement here. I got some oak and made an architrave out of it.
Fully seasoned in a closed shed and kiln dried before that...after the
winter CH, its now got 0.5mm gaps between all the sections.
We cut green wood and leave it in piles in the rain for a year or so..
Then it gets split and shoved in te back of a tarp covered Land Rover
which is the wood store. After a week,it doesn't hiss when you burn it.
It's sopping wet when it goes in to the Land Rover. Ergo, its ACTUAL
content even in the rain is pretty low, and pretty much superficial.
Once the wet exterior dries off, its about as dry as it would have been
being stored under cover. The only difference is the parts that stay
permanently wet, get amazing fungal growths all over. Those are surface
only, until they break the wood down enough for rain to penetrate further.
So my feeling on this is that once cut, wood dries unless its buried in
wet soil.
Even in the rain. There are dozens of dead trees in the local woods, all
stripped of bark., They fall over, and the wood is actually dry and not
rotten - only where ground contact exists does it rot. So I think all of
this bunk about wood treatment is just bunk. Fell it, plank it to stop
it splitting, keep it off the ground, and leave gaps between planks to
prevent water spooling, and it will be usable timber in a year and even
rain on it won't hurt, as long as it can evaporate off reasonably fast.
Its moisture content will stabilise at the average sort of 'outdoor'
level whether it's covered, or not. Around the stated 15%-17%
level..what is green wood? 50%? anyway the bulk of the moisture simply
leaves it.
THEN if you want it for joinery, it needs to ebe moved from he
cellar/shed into the house, and left for about 4-6 weeks ideally. Then
machine it to size.
Timber merchants store presure treated constructional wood outside,
uncovered.
Its no big deal really.
Stuart Noble
> So my feeling on this is that once cut, wood dries unless its buried in
> wet soil.
Or at the bottom of a lake, which used to be common practice in Scandinavia
>
The Natural Philosopher
> On Fri, 28 Mar 2008 11:02:36 GMT, Stuart Noble
> <stuart_no...@ntlworld.com> wrote:
>
>> It's reckoned that wood dries outdoors to a moisture content of 17% in
>> winter, and 15% in summer. This is what you expect joinery quality from
>> a timber merchant to be. But for indoor stuff and furniture, it should
>> ideally be around 10%, which is only achieved by keeping it indoors for
>> a few weeks. In an ideal world you wouldn't plane the timber until then
>
> seasoning planks for joinery or firewood?
>
> If we're talking about a modest amount of planks and the cellar is not
> naturally damp then worst case is you'd need to add a small fan to one
> of the vents. If you're talking about dobbing a whole heap of fresh
> logs onto the floor then you'll have problems getting enough air
> through the heap before it starts rotting, which means both loss of
> dry matter and production of more water which needs carrying off.
>
> Even so split logs do dry out ok in my brother's redundant pig shed
> over a summer with natural ventilation, that's the key, passing enough
> m^3 of unsaturated air through the heap.
>
Well how much water can there be in a cu m (a few tonnes) of logs? 500
liters? and that takes about a year to dry..so thats as much as ..gasp -
10 liters a week? Gosh thats nearly a liter a day..spread out over an
area of lord knows how much. Hardly taxing is it?
> AJH
>
Andy Wade
> Well how much water can there be in a cu m (a few tonnes) of logs? 500
> liters?
Bzzt. Most woods will float in water so the density must be less than
one tonne per m^3. IIRC for most species it's in the range 600 - 750
kg/m^3 - hardly "a few tonnes." At 20% MC your 500 litres comes down to
120 - 150 litres in reality.
--
Andy
The Natural Philosopher
that much water in wood, and over a year, the evaporation rate is really
miniscule.
The Natural Philosopher
> On Fri, 28 Mar 2008 18:27:13 +0000, Andy Wade
> <spamb...@maxwell.myzen.co.uk> wrote:
>
>> Most woods will float in water so the density must be less than
>> one tonne per m^3.
>
> and the bulk volume doubles.
>
>> IIRC for most species it's in the range 600 - 750
>> kg/m^3 - hardly "a few tonnes."
>
> beech but that contains about 47% water.
>
>> At 20% MC your 500 litres comes down to
>> 120 - 150 litres in reality.
>
> about 500litres of water, you need to drop that to 25%mc wwb to avoid
> most microbial activity, that's about 155 litres remaining. Aside from
> any water formed by respiration of dry matter this 345 litres of water
> has to leave carried away by air and that air has to provide the heat
> to change the state of the water from liquid to vapour.
No heat is required: All that is required is that the air is not
saturated with water.
> At 20C
> saturated air can carry about 20 grammes of water per m^3, with
> natural draught and our humidity I'll doubt you can get within half
> that and a stack off logs won't have good circulation. It looks like
> about 34k m^3 of air needs to move through the logs. Say the volume
> passed by a psu fan for 33 days when humidity is low and temperatures
> are above 20C. With the caveat that the logs have to be chopped small
> enough for the interior to remain at equilibrium with the surface
> during that time.
That doesn't happen. Logs dry out on the surface first, and then a
gradient is set up. The initial dry is quite rapid - days only..its
getting the core water out that takes the time, hence the need to plank
and stack.
All that is required really is to find a place where the air is
unsaturated, and stays that way. Kiln drying works to speed this up, but
its not essential, and arguably doesn't actually do any more than
rapidly reduce the overall humidity of the wood, the actual achievement
of equilibrium happens later over time. Fresh kiln dried wood is still
highly prone to movement afterwards.
For that reason its unlikely that unheated wood will dry properly in
less than a year or so, not for joinery purposes anyway.
At which point the required air movement is far far less.
>
> AJH
>
Stuart Noble
> All that is required really is to find a place where the air is
> unsaturated, and stays that way.
Tropical hardwoods air dry very effectively at close to 100% RH
d...@gglz.com
The Natural Philosopher
;-)
The Natural Philosopher
Not bad, but it does miss one point: That not only will you get
splitting due to differential drying, but the rate of expansion and
contraction of the wood is radically different between three axes -
along the grain, radially from the heartwood and tangential to the bole
circumference.
A thin cross section of a trunk will ALWAYS suffer radial cracks no
matter how carefully it is dried unless the water content is held high
by soaking the wood in some form of water retaining or water replacement
chemical.
This actually presents the wood processor with real problems. Thin
sheets will dry faster, without splitting, but may end up warped on
drying. And cannot be made to bigger sections thereafter. Ultra thick
sections will crack anyway regardless of the drying regime.
One appreciates why so much wood ends up as pulp or chipboard..the
wastage is pretty massive. The wood processors I have spoken to, reckon
on about 40% wastage in most bulk bouht timber, for one reason or another.
I was not aware of the property changes in dried wood, except in a crude
subjective way: green oak works much easier than dry, and green willow
splits more easily than dry.
I had also not appreciated the sterilization effects of kiln drying.
And, whilst extremely informative, it didn't really answer the question
of "how long and how much ventilation?"
The very best book I have found on wood as an engineering material is
'Understanding Wood' by an America Author - Hoadley.
I must replace my copy. I gave it to the carpenters who built my house..
It's an absolute must for anyone doing more than nailing softwood
together for frames..
andrew heggie
> air has to provide the heat to
>> change the state of the water from liquid to vapour.
>
> No heat is required: All that is required is that the air is not saturated
> with water.
It's simple physics, if you remove water by saturating or increasing the
RH of a volume of air you either provide heat at 2.3MJ/kg of water
vapourised or the air temperature drops.
I shall not comment on the your further naive assumptions about kiln
drying.
AJH
The Natural Philosopher
> On Sat, 29 Mar 2008 10:14:41 +0000, The Natural Philosopher wrote:
>
>> air has to provide the heat to
>>> change the state of the water from liquid to vapour.
>> No heat is required: All that is required is that the air is not saturated
>> with water.
>
> It's simple physics, if you remove water by saturating or increasing the
> RH of a volume of air you either provide heat at 2.3MJ/kg of water
> vapourised or the air temperature drops.
>
latent heat of evaporation of a few kliograms of water is not exactly
massive..
> I shall not comment on the your further naive assumptions about kiln
> drying.
Whats up with you anyway?
Wrong time of the month?
>
> AJH
>