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Home insulation & RT2012


monsieur macon
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Following the thread concerning the heating of water, efficiently; it seems worth while considering the merits of fully insulating a house in the knowledge that energy prices are never going to come down, but in fact continue to climb. Having just moved into a house certified BBC "batiment basse consomation", with fully insulated roof (300mm), walls 180mm, floors150mm, i was astounded at just how little energy is needed to heat the house and how the house maintains this heat over a long period of time, without cooling. Having worked on a number of reno projects here in France, I have to say that on any future job I would certainly push the merits of thoroughly insulating.

Is anyone on this forum now living in a RT2012 house of even a property that is certified "energy positive"....the kind of house you can heat with a lighter!!! ???
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Are you really talking about 'energy positive' or are you talking about 'passivhaus' (passive house) as they are two different things. The first is obviously energy efficient with regards to insulation but more importantly it creates more energy than it can use via electrical solar panels (plus/or wind generation or in more general terms creating more electricity than what it requires). The second is a house that is built to such high insulation standards that it needs little or no heating.

The RT2012 started in 2000 with RT2000 then RT2005, RT2010, RT2011 and now RT2012. Each one, as technology becomes available, are a set of regulations to which a house must be built to in France. France jumped the gun a little in 2000 by creating regulations on the efficiency of new built houses. It is actually an EU directive 2002/91/EU and all EU countries are trying to implement it which includes most recently the UK. If you are renovating then you need to keep to RT2011. This year the government decided to stick with the RT2012 standard till at least the end of 2015.

It is definitely the way to go, the financial savings on energy bills should be quite dramatic. If you voluntarily decide to move towards a passive house they will be even more so. A passive house must be a minimum of 90% efficient to get your certificate. These are sealed houses, part of the certification involves pressure testing the house to ensure it does not leak. Whilst not exactly requiring a candle to heat the minimum standard is 15 kWh per M2 per year which for me and you means one small log burner to heat an average three bedroomed house.

Have to say my reason for wanting to built one is not to be ''green' but because I don't want to spend all my pension trying to stay warm in winter (and cool in the summer) yet in a way the two of course are linked. The problem at the moment is cost of building which go up and down like a yoyo. The price of existing technology is reducing but at the same time new technology is coming on stream and that is expensive. Insulation is a classic example, the equivalent of 200mm can now be reduced to 10mm (or there abouts). When the first thin type insulation came out it was so expensive now it is quite cheap by comparison. Heat exchangers are the same, the standard set five years ago that cost a lot of money can now be bought for a fraction of the price but the newer even more efficient versions are quite expensive. Its a bit like buying a computer, the day after you buy yours a new better one comes out and you can buy yours for half price.

Source for RT2012 - http://www.rt-batiment.fr/

Passivhaus UK - http://www.passivhaustrust.org.uk/

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We've had a 'BBC' house built and we moved in in March this year. The builder said it would be €30000 more expensive than if we hadn't had BBC, but we were working to a budget (and so therefore was he) and we achieved everything we wanted in the house for the original budget.

Apart from the huge energy savings, I reckon that in future, with energy costs constantly increasing, it will be far more saleable than a less energy efficient house.
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Thanks for the very concise replies......yes, i can well believe that a new build with RT 2012 must be extremely comfortable. I've heard of people almost heating the house with their cigarette!! Perhaps a slight exaggeration, but maybe i should take up smoking!!!

It is certainly the way forward. I think France has relatively low energy costs, certainly EDF being practically all nuclear its almost the cheapest in Europe, as was pointed out in another message. Be that as it may, costs are going to increase, and anyone thinking of a long term investment or just not wanting to through euros quite literally out of the window, would be wise to invest in a well insulated home. Again, log burner was on for around 3hrs last night, this morning the house is at 25C and will be at around 22/21C tonight at 20.00!!! The laws of thermodynamics have been halted - at least in my house...

Options for renovation which have had the chance to use are insulation by the exterior of the house. You attach the insulation required to the facades, essentially closing the house in a bubble of insulation - highly efficient, but a little costly!!!
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[quote user="monsieur macon"]Options for renovation which have had the chance to use are insulation by the exterior of the house. You attach the insulation required to the facades, essentially closing the house in a bubble of insulation - highly efficient, but a little costly!!![/quote]

Assuming your 'Tax Resident' you can get tax credits for quite a lot of this type of work on renovation if it is your principle home. If you are on a low income (up to €30,000 per couple pa) then you can also apply for an interest free 'eco loan' for up to 15 years in some cases as well. The whole job (or jobs) must be done by a registered French builder and to get the €30k you must complete three 'elements'. In other words three seperate types of works  and there are around 18 of them.

I know three people who have had insulation added, one to the outside and two to the interior. The person who went for the exterior said he went that way because he didn't want to reduce the size of his rooms but we are only talking about four inches maximum plus it is quicker to instal and less expensive.

To get any of these tax credits and loans your house must be built before 2011.

Source - http://www.french-property.com/guides/france/building/renovation/energy-conservation/

Original Source - www.ademe.fr

For those who may pick up this thread next year or even later the percentages of tax credit may have changed like all things in France nothing stays set in stone for long. The current rate will always be on the french website (second link).

 

 

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The reason for adding insulation to the outside is to prevent cold bridging at internal wall junctions. 

It is such a worry to some about reducing the internal size of their rooms but you really won't miss 100mm or so but you would love the comfort factor and the wallet factor.  Once done people love to talk about it [:)]

So following on from your other thread and this one a bit [;-)]  I have invented the Passivpool, or Passivpiscine if you prefer,  90% more efficient than a conventional pool.

 

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The two I have seen it is not even 100mm with this modern silvery sandwich stuff more like 50mm. Actually moving between two rooms, one insulated and the other not (waiting to be done) the only way you could tell was one had plaster board and the other still had wallpaper. You can feel the difference moving between rooms. They are doing the ceilings as well (they are both single level houses). I asked why not put it in the loft and they explained that you can never quite get the insulation right in to the edges plus there is a lot less 'itching' involved and it is easier.

So following on from your Passivpool your getting 90% of the way to openly advertising. Just keep it in your signature and you won't upset anyone. [;-)]

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[quote user="Quillan"]

The two I have seen it is not even 100mm with this modern silvery sandwich stuff more like 50mm. Actually moving between two rooms, one insulated and the other not (waiting to be done) the only way you could tell was one had plaster board and the other still had wallpaper. You can feel the difference moving between rooms. They are doing the ceilings as well (they are both single level houses). I asked why not put it in the loft and they explained that you can never quite get the insulation right in to the edges plus there is a lot less 'itching' involved and it is easier.

So following on from your Passivpool your getting 90% of the way to openly advertising. Just keep it in your signature and you won't upset anyone. [;-)]

[/quote]

[:D]

The point about loft insulation is you are not supposed to get it right to the edges, you must stop short to allow airflow on the cold side.

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[quote user="Théière"][quote user="Quillan"]

The two I have seen it is not even 100mm with this modern silvery sandwich stuff more like 50mm. Actually moving between two rooms, one insulated and the other not (waiting to be done) the only way you could tell was one had plaster board and the other still had wallpaper. You can feel the difference moving between rooms. They are doing the ceilings as well (they are both single level houses). I asked why not put it in the loft and they explained that you can never quite get the insulation right in to the edges plus there is a lot less 'itching' involved and it is easier.

So following on from your Passivpool your getting 90% of the way to openly advertising. Just keep it in your signature and you won't upset anyone. [;-)]

[/quote]

[:D]

The point about loft insulation is you are not supposed to get it right to the edges, you must stop short to allow airflow on the cold side.

[/quote]

Bet you didn't know I have never insulated a loft. [8-)]

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Well while I have been working I was thinking about that. My house is double brick (well the outside is concrete blocks, the inside is the red blocks and in between is 100mm of rockwool). The insulation in the roof is up to the edge all the way round and we have vents in the loft wall at each end and these funny looking tiles on the roof that let air out. I assume that with them all working together they allow air to circulate inside the loft area. As I say I am no expert but I do remember our houses in the UK having insulation almost, but not quite, to the edge but then they were brick outside and plasterboard on the inside. Perhaps with things like different construction methods between the UK and France, different roof pitch etc insulation is fitted differently between countries?
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  • 2 weeks later...
My brother has started the building of a house at the top of our field, using a system of polystyrene blocks in-filled with cement which gives a high insulation value. His aim is to have a house with as low a heat loss as possible.

So far the foundations and walls of the cellar have been constructed, which will be across the front of the house. There are pictures here if you are interested in the construction method:

http://s75.photobucket.com/user/Bouillaguet/library/Richards%20House?sort=2&page=1
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Insulated Concrete Formwork, (ICF) construction is a fast way of building that can exceed passivhaus specification.  From the photos there seems to be a lack of lateral re inforcing bar especially at the corners and expanded polystyrene should have a self adhesive, usually bitumen, damp proof membrane applied to below ground structures like basements and swimming pools,  The use of extruded polystyrene can do away with that issue.  It is very important that a sealing strip, often made of bentonite material is used between the concrete base and the walls to prevent water penetrating between the inevitable gap that will exist between the poured based and newly poured walls and first and subsequent pours when carrying out two storey builds.
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I'm sure the steel is in there, probably below the line of sight, as in this example.

 

[URL=http://s857.photobucket.com/user/nomoss/media/Posted%20on%20Forums/ICF20Example203_zpsbe2db46c.jpg.html][IMG]http://i857.photobucket.com/albums/ab131/nomoss/Posted%20on%20Forums/ICF20Example203_zpsbe2db46c.jpg[/IMG][/URL]

 

And the waterproofing of the outside will be done once the concrete has gone off, before back-filling.

 

 

 

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You are both right - the steel is in there and the waterproofing will be done once the last layer of blocks for the cellar walls are in place, before the back-filling takes place. The cellar is only across the front third of the house.

The manufacturer's agent has been most helpful and spent a lot of time helping and advising OH (who's doing most of the work) about the correct techniques and is available as and when required as the building progresses.
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I like the photos...this seems exactly how you build a swimming pool out of blocks and concrete, with the iron work inside. Not quite sure why you would want to build a house like this apart from if you have seismic, thermal or other similar particularities concerning the build? I notice that the house is quite deep into the ground with obviously a garage or cellar on the ground floor. The compression of the earth against the house walls will of course be considerable once the earth is put back in around - again much like with a pool. Is there a reason why the house is burried this deep into the ground? Is there not going to be a risk of flooding or humidity (even with a solid damp course being used)?

In any case. Im about to add an extension of around 30m2 to our house which is a 1993 construction. Whilst im not obliged to use RT2012 building regulations, I will be using RT2005, thus 100mm insulation for the walls: 300mm for the roof and probably 150/200mm for under floor. All windows will of course be purchased new, thus will be RT2012 conform.
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Have come late to this fascinating thread. Is the posted picture of interlocked poly blocks with the steel inside that form the mold for the poured concrete? Looked at the photobucket pictures and only the inside seems to be supported, not the earth side during the pouring. Amazing strength if that the case. You might also be interested to know that all your photo bucket pictures are available to view, not just the construction ones. I had a similar problem posting some recently, did not know in doing so all were then visible!!
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Once the last row of blocks go on (hopefully next week if there's a dry day) and they are then filled with concrete the supports on the inside will be removed. It is amazingly solid once the cement has set. There was one panic the first time the cement was delivered as, although the driver was told to pour the cement slowly he didn't, resulting in a breach at the bottom of part of one wall with cement pouring everywhere across the floor like an incoming tide! It took a lot of hard work on behalf of OH to clear it up before it started setting.

Thanks for the reminder about all my photos being available to view. I did realise, but I don't think there is anything that I wouldn't want to be seen on there, or is that asking for trouble?
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[quote user="Rob Roy"]Once the last row of blocks go on (hopefully next week if there's a dry day) and they are then filled with concrete the supports on the inside will be removed. It is amazingly solid once the cement has set. There was one panic the first time the cement was delivered as, although the driver was told to pour the cement slowly he didn't, [/quote]

Yes if there has ever been a time in your life when you need a shotgun, that is it, to convince them to pour slowly and start at the corners first!

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Oh Yes! OH was so angry he ordered the driver to stop and leave - the cement company have not charged for that delivery! A few days later the manager of the cement company, the rep. of the building system and the manager of the builders merchants were all on site, as demanded by OH, to see that the cement was delivered correctly! We've had no problems since!
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