Topic: Piles/Tmber Floor or Concrete Foundation

Piles/Tmber Floor or Concrete Foundation 

I am looking to build a 130 - 150m2 home in the Christchurch/Selwyn area and I am not sure if timber or concrete floor would be better, both in cost and energy efficiency.
I was originally wanting concrete, with well above code poly and then polished concrete floors to rooms on the north side, but have since been in several homes and its just too harsh. I have gone back to considering timber piles for a couple of reasons,
One is I can put a larger amount of insulation and also can access plumbing easily if need be.
Can anyone give me the approx costs for each and any advantages/disadvantages to each?

Re: Piles/Tmber Floor or Concrete Foundation 

Concrete floor every time.
Simple reason, you can fit water pipes and have the best heating system available.
At the present time the most cost effective way of heating is with an air sourced hot water heat pump.
A 150sqm home would be about $15,000 fully installed.

You can't fit a decent heating system to a house with wood floors.

JK

Re: Piles/Tmber Floor or Concrete Foundation 

Wouldnt be in the heating industry would you lol!
I have been in the industry and hydronic heating isnt soemthing I would personally ever use unless I had a large concrete monster of a house. Too much to go wrong and I have yet to see a air to water heatpump that can handle the below zero effectively.

Re: Piles/Tmber Floor or Concrete Foundation 

Yes, I do underfloor heating.

It's by far the best heating system for any size of house - and I can't understand why you think there is too much to go wrong. Um...a circulating pump, an outdoor unit - possibly an expansion vessel. The pipe is expected to last for at least 50 years.

As for outdoor units, our latest ones are have been designed and rated down to -20c, (for the European market). Show me something more cost effective and I'll sell them.

The next best alternative is a pellet boiler, higher capital cost, higher running cost.

Don't forget of course that when underfloor heating with a heat pump it can be run in the day when it's not freezing.

What sort of heating are you thinking of?

JK

Re: Piles/Tmber Floor or Concrete Foundation 

I would love to hear which air to water heatpump can run the 150m2 hydronic heating and how much it costs? I would expect at least something between 5-8 kW... Cheapest thing in Europe would be 10K NZD.

As for the hydronic heating, many people complain that it is costly to run, but they go for the cheap/nasty version where they just tie the pipe to the mesh and pour concrete over it. This way of installing would require min of 200mm poly if you don't want to waste at least 50% of your energy... If you did go for extremely well insulation, that would be the way to go.... Otherwise, you have to install a floating 50mm screed with pipes in it and poly under it... this would not work with 15000 total cost...

Dejan

Re: Piles/Tmber Floor or Concrete Foundation 

The proper way to do it is a slab with perimeter insulation, polystyrene on top of it, the UFH attached to the poly and finished of with 50mm screed.

Re: Piles/Tmber Floor or Concrete Foundation 

That's how I am doing it, but that will not fit in the 15000 NZD... And if you doing it this way, you don't require slab perimeter insulation, but the screed in each room should have insulated around perimeter so it does not touch the wall directly...
I have the peak load and heating demand calculated and all the distances for the pipes have been calculated accordingly with run lengths/pressure drops and temperatures adjusted for each heating loop...
Every component specified for the system has then been put together and shipped from Europe by the same people. Not to forget the heating screed additive, because raw cement screed does not handle the temperature changes (same as concrete). The screed has to be cured for a few weeks by lifting the temperature by a few degrees every day until the water comes to 40 degrees and then the whole thing backwards until you are back at 20 degrees.
Water flow in each loop is controlled by vents that talk to thermostat in each room. You can also achieve the desired floor temperature by putting a thermostat that measures floor temp via infra red sensor in case you have some flooring that is sensitive, or you want warmer floor in your bathroom or similar.
The entire system is by German company Roth...

http://www.roth-werke.de/roth-en/167.htm

The poly also has a heat reflective top foil and is 35mm... Screed is 45 mm.

Dejan

Re: Piles/Tmber Floor or Concrete Foundation 

sorry... "controlled by valves" not "controlled by vents"

Re: Piles/Tmber Floor or Concrete Foundation 

Agree with you but I still think perimeter insulation should be done as the walls should not have "cold feet"

Re: Piles/Tmber Floor or Concrete Foundation 

At this stage it looks like a log burner and Mitsubishi Lossnay system, and also undercarpet heating in each of the 3 bedrooms.
Also what is the point of pointing in hydronic heating when a large portion of the house is going to be carpeted with good quality underlay?
If I did go for a large system like this it would be radiators so I have more control over the system.

Re: Piles/Tmber Floor or Concrete Foundation 

As with everything involved with building a house, cost effectiveness is paramount.

Importing specialist product from Germany is a waste of money for New Zealand, using thin screed over insulation is also pointless. An air sourced hot water heat pump heating a 100mm slab on top of 40mm insulation, without anything round the perimeter, will cost well under $1000 a year to heat. All rooms warm, all through the winter.

Carpet can be laid over underlay that allows the heat in the floor to escape - the quality is irrelevant.

Log burners are fine, but specifying radiators in a new house is a real retrograde step.

When you realize that heating controls are efficiency saving devices - and that underfloor with a heat pump is so much cheaper to run than anything else - the solution is clear.

Fit pipes in the slab for the ultimate in future proofing.

Re: Piles/Tmber Floor or Concrete Foundation 

What's wrong with German equipment?
Often the best value for money.
They are World leading in energy efficient heating and building technology and their building methods are far more cost efficient in the long term than ours whether it is a wooden house or other...
I wonder how future proof is piping in the slab if power prices double or triple? Do you still want to heat the entire thickness of a slab?? Or if a defect in the pipe needs to be repaired? Screed can also be removed and replaced without demolishing the house if new pipes are needed in 30, 40 or 50 years time.
I would not go for the slab pipe shortcut and always use pipes in screed. And in is far better to control the temperature in the ever changing NZ weather.
Plus a well built house will not need to be heated for long in NZ conditions and adding all that up it is a clear win for the screed solution.
Screed can also be placed in top of wooden floors if the structure underneath is designed for the weight.

Re: Piles/Tmber Floor or Concrete Foundation 

Nothing wrong with German equipment - but NZ (particularly the South Island) has some important differences to Europe.
Electricity in NZ is much cheaper relative to gas than in Europe.
Bottled gas and diesel work out about 20c a kWhr here - ie similar to electric. An air sourced heat pump is say 5c/kWhr (at 4:1), pellets around 10c/kWhr.
Pex pipe fitted into the slab for heating is a world specification, expected to last at least 50 years. One big advantage with a 100mm slab rather than screed is thermal capacity. A relatively small heat pump run during the day is efficient and prevents significant fluctuations in temperature. Slamming 30kW into a screed for quick response is inferior in terms of comfort levels. There won't be significant temperature changes in a house with a thick slab.

If electricity prices become excessive, ANY other heat source can be fitted instead. (I've converted three systems from diesel as a heat pump was so much cheaper to run).

Pipes in a 100mm slab are superior for NZ conditions - and always will be. Of course it's better to have decent windows, extra insulation, perimeter insulation etc etc, but a thermal mass slab is suitable for any type of house construction on top.

Re: Piles/Tmber Floor or Concrete Foundation 

to caziques:
Particularly the South Island has a climate similar to European temperate climate. If you are building and specifying to current energy price in NZ, good luck! If you also rely on the COP that is written on your "OEM - made in china" heat pump, also good luck... You might find that the actual COP is rather between 2 and 2.5 (particularly when the temperatures go below 0 and when you actually need heating)...
Pex pipe fitted in the 100mm slab is a world specification but only with extremely good insulation under and around it... The way you do it (40 mm of EPS and no perimeter insulation and not to mention the 90mm walls) is not good even for the Auckland climate... in fact, such heating is not even worth considering...
If you are building to the minimum budget, I would suggest you stick to a log burner and some sort of ventilation/heat distribution, rather than the going for "wanna be underfloor heating" system.
Also, a 45mm screed requires far less energy to get heated and will hold the heat longer than your 100 uninsulated slab for sure...
And finally, your "NZ Conditions" should probably land on that list of myths... right on the first place. Temperature, humidity, wind and rain, if you haven't heard so, are common all around the globe... Wind being a bit more drastic in Wellington, but everything else being extremely similar to many, many places around the globe... THERE IS NO SUCH THING AS NZ CONDITIONS... there is NZ tradition, NZ culture, NZ whatever, but everything else can be found elsewhere...
One think though, I do agree with you... the heat source can be changed any time for one or the other way of doing it, but your pex pipe tied to the mesh, I am sure you will never get out again...

Dejan

Re: Piles/Tmber Floor or Concrete Foundation 

"An air sourced hot water heat pump heating a 100mm slab on top of 40mm insulation, without anything round the perimeter..."

You totally ingnore the basic principle of insulating first and heating second. EVERY penny plugged into ANY heating system is a waste of money if you make no effort to keep that heat in, you're basically heating the outside. Insulating the slab perimeter (via ICF or similar) costs a couple of grand, money much better spent than putting pipes into thermally inefficient slab.

"...but specifying radiators in a new house is a real retrograde step."

Utter rubbish and a typical comment from someone with a vested interest. .

Re: Piles/Tmber Floor or Concrete Foundation 

""Pipes in a 100mm slab are superior for NZ conditions - and always will be. Of course it's better to have decent windows, extra insulation, perimeter insulation etc etc, but a thermal mass slab is suitable for any type of house construction on top"".


This is a statement of a typical NZ trades person who sells a product without knowing much about it or the concept.

You claim that your system is suitable for any type of housing. You should be honest to the customer and say if they don't build a thermally efficient house on top of it they might not be able to afford heating later on. Lucky there are some competent people in NZ with German or other European background who understand the whole concept of warm and energy efficient building.
If one has to choose between a poorly insulated NZ standard house with poorly insulating aluminium windows and your system in the floor.
Or a simple but highly thermally efficient modern standard house with a wood burner, I would choose the second one.
And when do you people stop the unique NZ conditions nonsense????

Re: Piles/Tmber Floor or Concrete Foundation 

According to ‘guess what?’ our building industry should be importing German expertise and systems - all designed to service a population 100 times greater than ours, ignoring massive freight costs to NZ and poor backup service. When I imported kitchens from Germany, they always arrived with at least one critical component missing or damaged with a three month delay in getting a replacement.

I am tired of reading ‘guess what?’ continual carping on how rubbish all NZ builders and Architects are when it comes to emulating the enlightened building methods as practiced in Germany.

I quote in part from ‘Spiegel Online International’ – Environment 15/3/12:

‘First the cherubs and ledges are knocked off from the façade. Then the plaster and the pediments are removed. The old wall disappears under insulation panels as thick as mattresses, which are then painted, and suddenly the old house is an energy-efficient house. The old decorative elements, which are now missing, are simply painted onto the exterior. It doesn't make much of a difference visually, at least from a distance.’

‘When strolling past the historic brick structures in the Dulsberg section of Hamburg, Albert Schett of the city's monument preservation office, points out the acoustic difference between insulated and non-insulated houses. “Listen," says Schett, as he taps the facades, which now consist of an insulating layer covered with imitation brick. "It sounds completely hollow. But what wouldn't we do to save a few litres of heating oil?”

‘There is another problem, however: the people who live in these thermally insulated houses and are complaining about their ‘poor ventilation behaviour,’ as a brochure published by the Federal Office of Construction calls it. Unfortunately, it's all too often forgotten that any insulation changes the interior climate.
For example, it can lead to mould spreading in places where it would never have been expected, like inside the roller shutter box, behind radiators and underneath the windowsill.’
‘When mould has penetrated supporting beams, the house has to be abandoned, particularly as the insulating panels become increasingly moist over time. "It's like putting on a wet sweater on a cold day," explains a construction expert.

"Yes, we're becoming the world's best insulators," says Boris Palmer, the Green Party mayor of Tübingen near Stuttgart, "and yes, we are deliberately spoiling our building stock”.’

Not much more to say really - Rex

Re: Piles/Tmber Floor or Concrete Foundation 

Sceptics

Since when does exchanging know how cost freight?
German farmers use NZ know how and a company in our area is exporting cow sheds to Germany, Russia etc...
Silly you if you import kitchens which can be easily made here.
Who is more credible? You with your denial attitude and your builders who have created houses which are in majority cold and damp or those in Europe, Germany or North America who made mistakes too in building and renovating but in the minority of houses and NOT denying but learning from it.
We all make mistakes but the worst one are those who refuse to learn from it because they are too proud to admit that things are not automatically right just because they have been done so in the last 40 years.
I am long in this industry and I have come across people like you who don't want lo listen...I f you are tired of facing the truth it is your problem...
The high level of respiratory disease in New Zealand are not coincidence it is caused by third world housing standards and poor design. I live currently in a "house" similar to the KH ones. It is not very old but drafty, cold damp and expensive to heat. The laundry, toilet, bathroom are the most sunny rooms.
Sure it was some stupid European or American who designed and built it :-( A Kiwi designer and builder would never do that. How can I dare to think that???????
It is a bit like your endless bla bla about climate change. You collect things out of the media which suit you best. The truth in climate change is probably somewhere in middle between your fanatic denial and the other extreme.





--

Re: Piles/Tmber Floor or Concrete Foundation 

This is the tirade from a one man crusade to change the NZ building industry that does not have the courtesy to acknowledge that there are many innovators designers and Architects who also wish to make a positive change such as changing “the high level of respiratory disease in New Zealand”.

You are well aware of this because I have told you on numerous occasions so a ‘denialist’ I can not be, as my building patents over 40 years will testify. Were you even born when I was specifying insulation?
This was prior to NZSS 1900 even having an insulation standard.

So “guess what?” anyone who disagrees with you or challenges you is a ‘denialist’. Three times you used the word ‘denial’ – those who know me would be highly amused at that definition because I tell them anyone using that term intends it in a derogatory manner to define ‘a person who will not slavishly follow the AGW propaganda’.
Instead, I say they should research science based on raw data obtained in the field, tested against a hypotheses and presented in a paper that is peer reviewed.
Not the bull---t derived from some IPCC computer programmer changing his mind and his programme every time he runs into the real world changes that are now increasingly diverging away from the IPCC claims.

So you are wrong yet again: I preach that anyone who denies climate change is a fool and note that those who think that maybe our Earth controls 95% of climate change, more so than mankind, are much more likely to be right.

But continue on with your ad hominem attacks – it defines the person you are.
Rex

Re: Piles/Tmber Floor or Concrete Foundation 

I must disappoint you I am not alone he here. There are many others who work in the same direction but don't post here.
I am very straight outspoken about this as we have no time to fluff around and wait for those who don't have the skills or willingness for progress.
We have so many sick people in all social backgrounds because they live in damp and mouldy houses. Some are not even aware of it.
And you don't want to admit that large scale change is needed to build healthier, warmer and well. ventilated houses

Re: Piles/Tmber Floor or Concrete Foundation 

Sorry to hijack my own thread but can someone give me approx costs for 150m2 of piled foundation/floor compared to concrete foundation in chch?

Re: Piles/Tmber Floor or Concrete Foundation 

I can tell you that if you had to do any substantial earthworks for either of those, that will be a big chunk of you investment in the floor...

Re: Piles/Tmber Floor or Concrete Foundation 

Hello Red & Black,

I was writing on healthy home construction years before “guess what?” joined Ecobob so his myopic strident comments annoy people like me who are trying to effect positive change.
You may have your thread back now.

Before you can obtain a comparison, we need more information on access, ground conditions, and latest assessment of earthquake effect, slope of site and your budget.
Most designers work backwards from a financial brief. If your budget is very tight then it is of no value discussing any under-floor heating system no matter how desirable.

If your site slopes more than a metre, then a conventional or deep timber pile foundation may well be the preferred method and that allows you to install additional under floor insulation when funds permit. Again, if you allow an additional 50mm plus stud height, then a screed heating system can be laid later.

I come across far too much theoretical justification for spending up large on all sorts of goodies, such as having the perfectly insulated, ventilated, space heated, solar powered, natural material, untreated hardwood timber, triple glazed, zero formaldehyde, VOC painted house - the list is endless and ALL is desirable - and rarely affordable for the average buyer.

These theorists would demand you spend your money the way they dictate, as a way to lift the value, comfort and safety of our housing stock at your expense, but this will always be a balancing act between what you can afford against what may be desirable to others following.

Now there are posters here that will say they can achieve all this with clever design, or special imported materials or direct buying. Don’t believe them: bright NZers’ have been attempting to achieve this utopia for as long as I have been around (a long time).
If there was some magic bullet it would have been found years ago. This does not mean we should not strive to improve and do the best we can with the budget dealt us.
Good luck.
Rex

Re: Piles/Tmber Floor or Concrete Foundation 

Don't mean to hijack the thread again, but here is some theory in practice for Rex...

Insulated Kingspan roof panels KS1000 RW 40mm cost here 120 NZD/m2 with basic coating... I have imported them at less than half price including shipping from Europe. Same brand, same product!
Another product that was offered to me at 11000 locally, I have paid it 4000 in Europe.. imported as well!
There are two more containers of goods traveling my way... same or comparable products you would pay at least 2 times more locally... The saving on a scale of a house is close to 100k NZD... Your statement about huge freight cost is not valid...

So not just theory as you say... maybe it has been a while since you have looked around or gone shopping overseas.

You have your opinion and please don't put it out as a fact just because you are backing it with some articles and research of the people who think like you. I have no idea what your background is, but some things are common sense and everybody should be able to build their own opinion.

Also, when you say: "According to ‘guess what?’ our building industry should be importing German expertise and systems - all designed to service a population 100 times greater than ours", do you really think that building technology is designed to a size of population or market, or to a certain functionality and purpose? Products like insulation or similar?
Some half-solutions that people are getting sold here are maybe the versions for a small population, or does the small population deserve better?
I have grown up in a country that has a population just a few times bigger than NZ and our local products were always far cheaper than the European ones though maybe not as great... how come a local product in NZ is more expensive than then any comparable product from technologically superior countries... and it is not just the technology, it even seems to be the case with the timber... Since you were around for much longer, can you please clarify that for me? I am trying to figure that one out, but no one can convince me that locally grown and processed timber land more expensive next door than when it travels around the globe...

I agree with your last post entirely and am reacting to the ones before, and doing so not to put the oil on fire, but to hopefully also learn something.
For example, one thing I have learned is: Don't mess with the tradition! I personally think that outwards opening windows are ridiculous for a few reasons. No way to wash them other than hosing unless they are on the ground floor, can not leave them open when you leave the house because it's unsafe, sooner or later they won't hold unless the hinges are so tight that it takes a pretty good push to open or close (NZ) - way more than 90N that are allowed by NZ4211...
However, I don't mess with that... If people like that I am not trying to change their mind, I only say what the benefits of tilt/turn windows are from my point of view and leave it there...
But when someone says that underfloor heating in a slab without a perimeter insulation on 40mm EPS is efficient way to heat the house, it does set me on fire... nothing I can do about that. Particularly when that comes as a suggestion/proposal and sealed with "NZ conditions".

Dejan.

Re: Piles/Tmber Floor or Concrete Foundation 

If you want to talk about windows why not start a thread about windows so it can be discussed on topic.

This continual " New Zealand is all bad, let's talk about my perfect European homeland" is childish and tedious.

Forums need moderators and I doubt this forum will ever work without one.