Browse Forums Eco Living 1 Dec 17, 2008 6:08 pm We are tossing up what floor covering to use in our living areas. The living areas are north facing, and so we'd like to maximise the thermal mass available from the slab.
We love the look of bamboo flooring but are worried that we'd lose the thermal mass. Does anyone know if using bamboo would be significantly worse than ceramic tiles laid directly onto the slab? Ta! Re: Best floor covering for keeping thermal mass 2Dec 17, 2008 6:13 pm Thermal mass is the capacity of the material to store heat, so anything that insulates the slab also prevents heat transfer into the slab - this includes the glue or tile cement. You need a black exposed slab during the day to soak up radiant heat and a slow release insulated slab at night. So you can have bamboo at night "ECOECO" At 'EcoEco', we design windows, we design the best windows, we do it for you, so that when you’re happy we are happy. Tel. 1800 326 326 Re: Best floor covering for keeping thermal mass 3Dec 17, 2008 6:19 pm We've had the same decision to make. We'd prefer some nice timber or cork floor, but they don't suit the passive design, so in the end we've chosen the chocolaty floor tiles for the North facing areas. With some Oriental rugs we're very fond of it should be OK.
Chris My father rode a camel, I drive a car, my son flies in a jetliner, his son will ride a camel.Saudi saying Re: Best floor covering for keeping thermal mass 4Dec 17, 2008 6:46 pm I would say that if direct sunlight hits the slab area in winter, then it's best to have tiles in that area. I wouldn't worry about the colour since what you don't absorb you reflect. Assuming you don't have a south window just a few metres from your north window, the light will bounce around in your house and ultimately either pass out a non-illuminated window (lost) or be absorbed further into your house. For the areas further into your house bamboo or wood would be OK since it's less intense light.
So in summary, ceramic tiles where direct sunlight hits and whatever you like (except carpet) further in. This is what I'm doing. Demolition August 2009, Construction Started September 2009, Completed December 2010 Re: Best floor covering for keeping thermal mass 5Dec 17, 2008 6:55 pm Thanks all, that's exactly what I thought. I was just hoping against hope that there was some other factor I hadn't thought of that would make bamboo a good choice I love it so... Re: Best floor covering for keeping thermal mass 6Dec 17, 2008 6:55 pm Casa2 . I wouldn't worry about the colour since what you don't absorb you reflect. , ceramic tiles where direct sunlight hits and whatever you like (except carpet) further in. I agree. It has been demonstrated that colour doesn't seem to have a major effect on the function of thermal mass (it could be related to what Casa2 has said but I don't think anyone has yet found a reason for this observation). You want to maximise materials with thermal conductivity. The glues don't seem to make that a much a difference (probably because of its thickness). Theoretically in order: Exposed concrete > Tiles > Wood > Cork/Lino/Vinyl > Carpet Wood has to be in direct contact with floor (not as floating/underlay or on battens). Remember the thermal mass should be thin and spread out rather than thick and concentrated for your purposes. Re: Best floor covering for keeping thermal mass 7Dec 17, 2008 7:21 pm Thanks dymonite. I forgot to mention that the wood can't be on battens. I think an underlay is OK and most of the underlays specify their thermal resistance which is pretty good. The denser the underlay the better, but it's not a big factor. Also, thinner wood (eg 22/14 mm) would be better than 19 mm, but again not a big factor. Battons and therefore an air gap - big no no. Demolition August 2009, Construction Started September 2009, Completed December 2010 Re: Best floor covering for keeping thermal mass 8Dec 18, 2008 7:49 pm As per above. any insulating material on top of ghe concrete will reduces it ability to absorb the heat.
Have a think about a simple exposed concrete with an epoxy coating on top of it. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ and if you used fly ash concrete - it is much nicer colour and is more earthy in colour. Fly ash concrete costs the same as cement based concrete, but the fly ash is made from waste producst from our pwoer stations. It's simply a case of asking for fly ash instead of old style concrete when you order it. Steve Re: Best floor covering for keeping thermal mass 9Dec 18, 2008 10:23 pm Steve,
Quote: Have a think about a simple exposed concrete with an epoxy coating on top of it. If you mean terazzo, it must be done by someone very good and requires top quality mixture. That costs money. Done on the cheap it cracks, I've seen it! Quote: but the fly ash is made from waste producst from our pwoer stations Fly ash isn't available here in the West. I also seem to recollect a lively discussion somewhere, with its opponents claiming that it contains radioactive stuff and nasty products of coal burning. That reminded me of a scandal I witnessed in my younger years when I was living in Poland. They tried to cut costs there by using fly ash to make concrete for the prefab building panels. Someone went into a finished block of flats with a Geiger probe, which promptly shot up past the safe limits. The building was left uninhabited and they stopped using fly ash. Chris My father rode a camel, I drive a car, my son flies in a jetliner, his son will ride a camel.Saudi saying Re: Best floor covering for keeping thermal mass 10Dec 19, 2008 10:44 pm Slab is already laid- we like the look of exposed concrete but decided against it as we weren't confident of the quality of slab-finish and on a poorly finished slab it can look awful. Re: Best floor covering for keeping thermal mass 12Dec 26, 2008 4:31 pm Thanks all! It's the same conclusion we'd reached but I was hoping their wouldn't be much difference and I could justify the bamboo Tiles it is. Re: Best floor covering for keeping thermal mass 13Dec 26, 2008 5:20 pm I still think the bamboo flooring would be OK. Just not on battens (direct stick or on plywood). Demolition August 2009, Construction Started September 2009, Completed December 2010 Re: Best floor covering for keeping thermal mass 14Dec 26, 2008 5:37 pm Diagree casa .
Quote: The R-value for a ¾" engineered bamboo floor is R=0.720, according to the Radiant Panel Association, RPA. The lower the R-value the better heat transfers. That r value would stop a lot gain going into the slab and resistance for it to come out. Plus other issues they talk about here re moisture - sun on it all winter may dry it out too much? http://www.buybassi.com/installation.html My thoughts Steve Re: Best floor covering for keeping thermal mass 15Dec 26, 2008 8:30 pm Yak_Chat Diagree casa . ]The R-value for a ¾" engineered bamboo floor is R=0.720 That r value would stop a lot gain going into the slab and resistance for it to come out. It is important to note that most thermal mass materials actually have a moderately high R-value (though not as high as proper insulation). This characteristic is important for it to achieve its function. If the R value is too low such as in copper (i.e. high thermal conductivity), the heat would pass right through to the other side and be lost. What distinguishes thermal mass is its ability to store a lot of heat energy with only a modest changes in its own temperature. In other words it has a high volumeteric heat capacity. Most of the heat energy in thermal mass floors and walls is stored in the first 15cm (it doesn't get very far due to medium R values). Increasing your thermal mass thickness won't give you more storage capacity. You can only do this by increasing the area over which you distribute it. Moreover, wood actually has useful thermal mass (although about half that of concrete). So whilst wood (or for that matter concrete) isn't the best insulator, its thought that the comfort of log cabins is partly related to its thermal mass properties. The reason why carpet flooring doesn't work is not just because it has a high R value. It also has a low volumetric heat capacity. When exposed to solar gain, its surface temperature rises quickly and re-radiates the energy back it into the room causing it to become uncomfortably hot. Timber on the other hand can accomodate some of that heat energy and buffer the temperature rise. It is conductive enough to transmit that energy into the slab as well. Re: Best floor covering for keeping thermal mass 16Dec 26, 2008 8:35 pm Hi Steve,
I'm going to get you to agree with me. Just give me some time. Now we have the R-value of 3/4" engineered bamboo floor is R=0.720 ft2°F.h/Btu. This is not too bad. Let's convert it to units everyone in the world, except the US, uses. 0.720 ft2°F.h/Btu = 0.13 m2K/W. An R of 0.13 between the concrete slab and the room is pretty good. I'm using wooden flooring over a slab with hydronic heating and I'm confident it will work well. Cheers, Casa Demolition August 2009, Construction Started September 2009, Completed December 2010 Re: Best floor covering for keeping thermal mass 17Dec 27, 2008 7:48 am I'll agree with you Casa and it is not as bad a carpet.
As you noted earlier - your putting tiles where the sun lands on your floors and bamboo elsewhere. Reason being - to get better heat transfer from the sun? Steve Re: Best floor covering for keeping thermal mass 18Dec 27, 2008 8:05 am The idea, in my case at least, is to put tiles where the sun directly hits to improve the thermal contact with the slab. However, for the bulk of the house, it's floorboards without an air gap (that is, no battens).
I'm happy to have timber flooring over an in-slab hydronic heater. Also, I should mention that I have both a suspended slab and a slab on the ground. For the suspended slab I will be insulating the underside. For the slab on ground I'll just be doing edge insulation (1 metre along the slab edge). BTW, while on the interesting topic of hydronic heating and carpet, I will be having hydronic heating and carpet in a couple of rooms. In this case I'm going to run the hydronic pipes into the inside brick wall. This way the wall between the two rooms becomes the "radiator". Demolition August 2009, Construction Started September 2009, Completed December 2010 Re: Best floor covering for keeping thermal mass 19Dec 27, 2008 8:16 am Casa2 R-value of 3/4" engineered bamboo floor is R=0.720 ft2°F.h/Btu. 0.720 ft2°F.h/Btu = 0.13 m2K/W. Another important point is that R-values in building materials is often quoted for the entire assembly and the metric units are: m2K/W (as quoted above) i.e. R values for a floor board, concrete block, fibreglass batt However, the thermal resistivity of different materials is usually quoted for a section 1 metre thick This is measured in mK/W Therefore to get the actual resistance to heat flow you multiply this figure by the thickness of the material (in metres). Beware of this distinction (one could be easily make this mistake and would lead to confusion). List of thermal conductivity for different materials using the second definition can be found here: http://en.wikipedia.org/wiki/List_of_th ... uctivities http://www.engineeringtoolbox.com/therm ... d_429.html Re: Best floor covering for keeping thermal mass 20Dec 27, 2008 9:26 pm casa said Quote: For the suspended slab I will be insulating the underside Good move - they get very cold in winter. Even a suspended fibre cement waterproof floor is cold in winter. dyno - theory is great - add in some real life experience and observation of the dynamics and we will see you as an eco architect sooner than you think. got it. thanks. I was looking for word ' Adobe' and added filter. all good. 12 14475 Appreciate that Chippy. I won’t do sand under pavers and will connect all up under pavers, however I was going to do: 1) Roadbase compacted with manual hand tamper 2)… 10 18563 CDC Housing Code 3 When to apply Floor Area external face of wall vs Gross Floor Area internal face of wall. Reading thru CDC Housing Code 3, lets take a lot 915sqm.… 0 16553 |