Holz Hausen Experiment - Results are IN!!

[Apprentice_GM]

one thing i am convinced on.... doesn't really matter what kind of stack but HOW you stack...etc <snip> so in summary : the method of stacking is not as important ...its how you stack it and your climate

OK, cool, but why? Have you done both and measured both? As I said before, I'd be happy if someone can save my time and effort!

Also, if that is the case, why have HH's been going for hundreds of years? I agree loose stacking is important - the HH I read says ensure a mouse can run between splits - but I think the method is important too. I will do my best to stack both the HH and the comparison rows with similar gaps - if I do this and the results show the HH is superior will you believe it?

Please, I'm not knocking anyone's experience, but I want to try and scientifically measure this and try and determine if an HH is better or the same or worse as normal stacks. I'm still keen for feedback, advice and suggestions on my experimental method, or proof by others who have done similar to save my time and effort.

 

[Apprentice_GM]

I think your endeavor is worth it and many here at the forum would probably check out a blog if you track weekly/monthly progress.

Thanks, that's encouraging.

I have three HHs built and enjoyed building every one. I laid two courses of brick staggered as a base on the last one to encourage airflow and chimney effect, I may try a smoke test like you suggested, but I wouldn't be surprised if the draw wasn't that much. I don't care about making things tight or filling gaps, I used a lot of shims to keep the angles correct which created pockets. I do try to stack upright as much as possible in the middle (rather than just lazy-like tossing stuff in middle which could cut off airflow). I wouldn't make my HHs larger than 6-7 foot wide, more smaller ones to me seem to make sense (again the more airflow and sun the better). I agree that the Europeans (Holz Haufen is German after all) would have chucked the idea of these a few hundred years ago if they didn't work. One thing I need to work on is a better methdology on creating a shingled roof to shed as much rain water as possible. One thing you may want to note is how dry your wood in HH remains even after a decent rain.

I might put a tarp or corrugated plastic roof on, but only on the top, not down the sides, it's important to keep all ends exposed for best seasoning. In fact, even on normal stacks I wonder about people who run tarps down the sides over the top half - maybe they only do that with a fully seasoned stack, or maybe they don't have the room to bring the tarp out horizontal so the top pieces continue to get airflow.

I also wonder about size - I have read a few articles saying don't go under 6' as you get little benefit, which makes me wonder why, and I come back to my theory about how they work (airflow across top creating low pressure and drawing air up as per my post above answering #6). I reckon the small HH's may not have the optimum top shape - easier when the HH is larger - hence reducing the pressure differential.

Anyway, great to hear from down under and good luck, I'll probably end up posting a couple pics of mine in the next weeks.

I'd like to see some pics, I enjoy the HH thread in the Perfect Pics forum.

 

[iceman]

one thing i am convinced on.... doesn't really matter what kind of stack but HOW you stack...etc <snip> so in summary : the method of stacking is not as important ...its how you stack it and your climate

OK, cool, but why? Have you done both and measured both? As I said before, I'd be happy if someone can save my time and effort!

Also, if that is the case, why have HH's been going for hundreds of years? I agree loose stacking is important - the HH I read says ensure a mouse can run between splits - but I think the method is important too. I will do my best to stack both the HH and the comparison rows with similar gaps - if I do this and the results show the HH is superior will you believe it?

Please, I'm not knocking anyone's experience, but I want to try and scientifically measure this and try and determine if an HH is better or the same or worse as normal stacks. I'm still keen for feedback, advice and suggestions on my experimental method, or proof by others who have done similar to save my time and effort.

what i am saying is no matter how you stack it (spaced rows or hh) in ideal cohave space and yonditions they will both dry in the same time. this come from the many different answers here.. i hope youe experiment will give us an answer but the key to hh is it saves space and looks pretty ... if you take the same 2.5 cds put them in the same space then the hh might be faster because of the design .. but if you stack rows seperated/ loosely it will dry just as fast.. wood seasoning in 3 months .... needs dry air , sun , and wind ....
but if you experiment works i will be building one too..lol
keep us posted and please show pics... good luck

 

[Rockey]

Regarding previous comments:

<snip>

6) I don't think the tarp suggestion is a good one. The idea of an HH is to draw air over all the splits towards centre, then up and out like a chimney. Covering most of the stack prevents this, prevents air being drawn over and along the covered split.

6 - Tell me, what exactly do you think is going to draw the air in to the center of the HH? Trust me, every split in the center of the HH is going to be colder and receive dramatically less airflow than the splits on the outside of the HH without the aid of a fan.

Well, I think it's simple, but obviously yet to prove it. My contention is the thing which seasons a HH faster than normal stacks is increased airflow (there is no doubt that increased airflow seasons much faster so it is reasonable to assume that this is the main reason for a HH). Your question is why?

Airflow, even very light winds, flow around the HH and over the top. When the top is shaped like a dome or pyramid/cone it creates low pressure at the centre - just like a wing (of a plane, chopper blade etc) and this draws air up the middle, or up the chimney. This air has to come from somewhere, as it in turn creates a low pressure zone in the middle of HH. The air then comes from outside the HH, flowing along the splits. That is the main point, and I know it's my theory not some learned scientists - well I haven't seen it elsewhere - and I have another, additional theory.

Airflow around the side of the HH creates similar low pressure points, again like a wing, or like a boat at mooring (this is why 2 yachts accelerate towards each other on moorings and bang into each other - benefit of a catamaran but that's a different topic). So airflow is increased even without the top or chimney effect. In other words, my contention is if you built a cylinder of wood up to a ceiling, so air flows around sides but can't flow over the top, you would still get an increase in airflow across the splits compared to traditional rows or stacks. A poster in another HH thread here postulated similar thoughts for this point, but didn't or couldn't try to prove it.

Ah, ok. It does seem that you have thought this through a bit. A couple things to consider - You need laminar airflow to produce the desired low pressure, thus creating the chimney effect. The rough edges of the HH will be mostly turbulent air. You will also need a decent prevailing wind to produce this chimney effect. If the prevailing wind is already present will the chimney effect really be significantly greater than a normal stack of wood in a prevailing wind?

I think most of the chimney effect will be from a Delta T especially in the morning when the outside of the HH is receiving abundant sunshine and the center of the HH is still cool from the night time entropy. I just think the difference between an Hh and a regular stacked wood drying time is negligable. I am very interested in seeing some empirical data from your testing, good luck.

 

[archer292]

I guess I am the culprit " it did not work". Sorry for the negativity. I did not mean that the HH will not season wood, I meant the 3 month claim is out the window, for me anyway. As far as why it has been used for so many years in Europe, I read somewhere that it had to do with limited space to store enough wood for a long cold winter. The size that are mentioned about the HH in Europe were 10 x 10. That is a damn big stack of wood. My HHs are 7 x 7. Maybe at 10 feet round the chimney effect is amplified compared to 7 foot. At 10 feet the center wood stacked end to end from the bottom would be a much larger cylinder or chimney going up. Anyway I will definitely follow this experiment as I am curious to see if the findings prove some of the claims. For me the limited space dictated where the HHs could stand and I think that "location is everything". That meaning the actual spot on the lawn for optimal air, sun etc., and the geographic local will all make a huge difference. It would be nice to know if it really does work better than straight rows but in the end given the same conditions and all, I don't think the difference is going to be too dramatic. I think the HH is useful for space saving and aesthetics and that's why I'll keep using it. I do like the chicken wire idea though. Believe it or not I dropped a 4 ft length of red oak around 18 inches in diameter from well above the stack, it just grazed it on the way down but bounced into it after hitting the ground. It knocked out one of the base pieces and caused some others to shift. It is still standing and I can still stand on the top without it coming down. Stupid test but I wanted to make sure it wouldn't crumble.

 

[pulldownclaw]

I'm also very interested in your findings. I am thinking about going with a HH with the stuff I'll be splitting next, mostly for aesthetics and space requirements. The area I want to stack isn't good for long rows, so I'm going to try the HH, and I think my 7 year old who loves to build things will be thrilled to help.

 

[sgcsalsero]

There is at least one German website that has awesome pics of HHs on it, buried somewhere in '07 posts here I think. Maybe worth trying to find/get in touch using BabelFish language conversion. Hey, why not go right to the source . . . .

oh and btw chipmunks (not mice) love my HHs, every time I walk past they are scurrying, so the air gaps probably are decent inside of it

 

[archer292]

These are some pics of the three i have in my yard. The views of the yard pics are from a second story window and the back slider. The pic with the HH and the stack was how my experiment started, and the tree is the red oak that was taken down and hit the HH on the right.

 

[Adios Pantalones]

I'm coming to visit

 

[archer292]

Anytime.... If it's cold bring some wood, mines not ready. lol

 

[sgcsalsero]

These are some pics of the three i have in my yard. The views of the yard pics are from a second story window and the back slider. The pic with the HH and the stack was how my experiment started, and the tree is the red oak that was taken down and hit the HH on the right.

Archer, to state the obvious you have a solid privacy fence, one of my HHs is 12" from my dilapidated garage so I've been concerned that the sun has been blotted out too much . . given more property I'd find higher and sunnier south facing ground, that -has- to be 50% of the battle with drying out. But then I have to ultimately get permission from my wife on where these beasties go . .and I think for most the -best spots- would get veto'ed by their significant other, mainly for appearance and safety concerns

. . anyway great looking HHs

 

[iceman]

I'm coming to visit

you should check to see which one seasons faster too

 

[ansehnlich1]

I had some holz's last year, they are real easy to tarp, but I don't think they season wood as good as stuff thats stacked in a single row and getting sun/wind all day.

No more holz's for me, my stuff is stacked straight line, facing south southwest, takin' a beatin' from the afternoon sun and prevailing southerly wind

 

[Apprentice_GM]

Nice HH's boys, you should post them in the HH thread in the Perfect Pics forum, they will get more exposure there - and they deserve it, very nice.

How long did they take to build?

 

[RedRanger]

Kinda reminds me of the movie --field of dreams-- build it and they will come.. Or try and build it instead of nice long rows in the sun and wind and? Well, who is fooled?

 

[sgcsalsero]

I found that German site, take a look http://www.holzmiete.de/

 

[Apprentice_GM]

That's a beauty of a site!

Some great Holz's there . . . some of the sloping roof pieces look a little unstable, like they might slide at any minute, but the hausens are terrific, really well built. I noticed one guy had a tarp over the top with no top hole for the chimney effect. Either he is missing some of the HH point, or the only point to an HH is efficient and aesthetic storage. I hope my experiment resolves it.

 

[iceman]

what a site! those pics were awesome! but i am convinced that eoropeans stack more that way due to space restrictions as many of those pics appeared to look like they didn't have much space...... makes me wonder if a guy had the special cover for his how well is the design gonna work as i would think more air would get out of one uncovered.. but then again some of those had such nice tops it could passed as shingles!!lol
keep the pics coming guys

 

[Apprentice_GM]

2) Split my timber and set aside 36 pieces. The 36 pieces will be 3 different timber types (probably 2 x hardwoods eg bluegum, turpentine or yellow stringy bark and 1 x softwood eg conifer) of 3 different sizes (small eg 1/4 of a 6" round, medium eg 1/4 of 10"-12" round and large eg 1/4 of 16" round) each of 4 pieces. These will go in the bottom, middle and top of the HH at each point of the compass.

I just realised my maths (no sic) was off. 3 x species x 3 x sizes x 4 compass points x 3 heights = 108 and that's just in HH, let alone some splits (+18) in the normal stacks. I will reduce this to:

3 x species in S/M/L splits in middle of stack at 4 compass points = 36 pieces.
1 x species in M splits at top and bottom of stack at 4 compass points = 8 pieces.
3 x species in S/M/L splits in normal stacks = 18 pieces
Total = 62 pieces.

We will then be able to compare seasoning of S/M/L pieces of 3 different species in HH vs normal stacks, as well as work out if the top or bottom or sunny side of the HH seasons better, if at all.

Unless I overlooked something

I have built my platform and setup my weather station, about to commence splitting and measuring and recording, hopefully this week. Spring has sprung Down Under, it's beautiful - birds singing, flowers blooming, rounds starring . . .

 

[sgcsalsero]

Assuming you gleaned a bunch of good info. on HHs by now, as you split up your stuff semi-sort it, stuff that is good for capping goes into one pile for me, nice looking shims into another, uglies for stacking in the middle yet another. Consider elevating off the ground, and/or make sure the ground has decent drainage. I put down 700 lbs. of gravel under one of mine, I think some guys throw a pallet in the middle and build around it.

 

[Apprentice_GM]

Yep, my platform is good, will post some pics later.

I have created one species - paperbark - with 6 x large (5kg splits) and 6 x medium (3kg) and 6 x small (1.5kg) splits already, and have identified some rounds of bluegum I will use to create 26 splits from (S/M/L similar to above sizes and weights). It's a bit tricky to get similar size rounds, well in the crappy, gnarly paperbark I had anyway, that I can split into similar splits. I am happy for a variation of say 10% in the splits, but would prefer 5% - I was constantly splitting small bits off larger splits today to bring it down to the right weight, then back to the scale, only to find out I had split too much off etc I know fossil would say it's not an exact science, and he's right, but I want to do the experiment as best I can in order to draw reasonably accurate conclusions from it.

I am wondering if I should start chainsawing rounds into 1/4's for better accuracy or reduced variation between splits. I will need to borrow or hire a bigger splitter too for the larger rounds and splits of bluegum, my little 7 ton electric can't manage them. I also need to find a better marking pen/pencil/crayon as my builders pencil and black texta/sharpie aren't coping well. The whole process is taking longer than I expected already

I need to get the vertical marking pole too, can't find anything appropriate in my scrap pile. Ah well . . .

 

[Apprentice_GM]

OK, I have started my HH experiment platform. I have decided to run a blog over on my website with constant postings here every time I do an update, and use these forums for feedback.

Holz Hausen Experiment - setup

When I have finished the experiment I might post the findings and blogs into a locked thread here. The idea is to keep the experiment thread clean and lean for easy future reference so others aren't wading through all the to's and fro's. I would do it all here but our webmaster can't create a thread only I can edit unfortunately. If anyone has a better idea I'm all ears.

As usual, suggestions and feedback encouraged!

 

[KeithO]

Guys, I lived in Germany and drove through quite a bit of Switzerland. The belief in Europe is that wood should not be burnt if it has not seasoned for at least 2 full years. Folks I knew who built HH's did so because it was less of an eyesore than regular stacking and generally people tried to have 4 winters worth of wood on their property, compounding the space issue. Wood burners there tend to be of the die hard sort. There are few places where one can get your own wood and property prices are astronomical (1.3 million Euro for 2-3 acre wooded site). So most wood burners either buy cut and split wood from landowners or get a permit to cut on state land, where one simply gets a better price but has to do all the work. One is escorted to the pre-marked trees for felling (sometimes they may already be down) and then in many cases one bucks and splits in the woods and transports it out. Most people are transporting the wood on small trailers towed by what are considered "compact" cars here. Generally less than a face cord per load.

So my take would be that it is primarilly an asthetic issue and that since they have so much rain, they get more waterproof wood piles without having to resort to the ugly tarp option.

 

[Apprentice_GM]

Having seen that german HH site posted earlier, and the beautiful HH's they build, under trees, complete with fake doors, windows and chimney pipes, I am leaning towards those reasons as well. However the fact remains that some people insist it seasons much faster in an HH. For example this link here:

http://www.thechimneysweep.ca/6seasoningwood.html

From a Master Chimney Sweep no less. So I am going to go ahead with this experiment . . . even though I am leaning towards it being a waste of time . . . on principle that I and everyone else on the internet should know once and for all. Hence my care with the methodology and measurements. Still open to feedback on that if there is improvement available.

 

[Valhalla]

OK men, this global interest in round wood (rund) ricks, aka HH is growing exponentially. Most important in our burning mission is the functionality of the wood drying and storage, besides keeping the wife happy!

I'll start one that is low enough that my wife can stack and then collect the needed splits. Report to follow.

Enjoy this burning issue. Keep warm, stack wisely and cut safely.